Russian Academy of Sciences

Landau Institute for Theoretical Physics

Previous seminars at the Landau Institute scientific council

Parallel SPH modeling using dynamic domain decomposition and load balancing displacement of Voronoi subdomains

14 June in 11:30

Maria S. Egorova, Sergey A. Dyachkov, Anatoliy N. Parshikov, Vasily V. Zhakhovsky

A highly adaptive load balancing algorithm for parallel simulations using particle methods, such as molecular dynamics and smoothed particle hydrodynamics (SPH), is developed. Our algorithm is based on the dynamic spatial decomposition of simulated material samples between Voronoi subdomains, where each subdomain with all its particles is handled by a single computational process which is typically run on a single CPU core of a multiprocessor computing cluster. The algorithm displaces the positions of neighbor Voronoi subdomains in accordance with the local load imbalance between the corresponding processes. It results in particle transfers from heavy-loaded processes to less-loaded ones. Iteration of the algorithm puts into alignment the processor loads. Convergence to a well-balanced decomposition from imbalanced one is improved by the usage of multi-body terms in the balancing displacements. The high adaptability of the balancing algorithm to simulation conditions is illustrated by SPH modeling of the dynamic behavior of materials under extreme conditions, which are characterized by large pressure and velocity gradients, as a result of which the spatial distribution of particles varies greatly in time. The higher parallel efficiency of our algorithm in such conditions is demonstrated by comparison with the corresponding static decomposition of the computational domain. Our algorithm shows almost perfect strong scalability in tests using from tens to several thousand processes.
Publications: arXiv:1805.05128v2 [physics.comp-ph] ; Computer Physics Communications, Volume 234, January 2019, Pages 112-125

Termal’nyi effekt Kholla kak topologicheskii invaraint

7 June in 11:30

Lev Spodyneiko

We show that derivatives of thermal Hall conductance of a 2d lattice quantum system with respect to parameters of the Hamiltonian are well-defined bulk quantities provided correlators of local observables are short-range. This is despite the fact that thermal Hall conductance itself has no meaning as a bulk transport coefficient. We use this to define a relative topological invariant for gapped 2d lattice quantum systems at zero temperature. Up to a numerical factor, it can be identified with the difference of chiral central charges for the corresponding edge modes. This establishes bulk-boundary correspondence for the chiral central charge. We also show that for Local Commuting Projector Hamiltonians relative thermal Hall conductance vanishes identically, while for free fermionic systems it is related to the electric Hall conductance via the Wiedemann-Franz law.

Dissipative and Hall viscosity of a disordered 2D electron gas

7 June in 11:30

I.S. Burmistrov

Hydrodynamic charge transport is at the center of recent research efforts. Of particular interest is the nondissipative Hall viscosity, which conveys topological information in clean gapped systems. The prevalence of disorder in the real world calls for a study of its effect on viscosity. Here we address this question, both analytically and numerically, in the context of a disordered noninteracting 2D electrons. Analytically, we employ the self-consistent Born approximation, explicitly taking into account the modification of the single-particle density of states and the elastic transport time due to the Landau quantization. The reported results interpolate smoothly between the limiting cases of weak (strong) magnetic field and strong (weak) disorder. In the regime of weak magnetic field our results describes the quantum (Shubnikov-de Haas type) oscillations of the dissipative and Hall viscosity. For strong magnetic fields we characterize the effects of the disorder-induced broadening of the Landau levels on the viscosity coefficients. This is supplemented by numerical calculations for a few filled Landau levels. Our results show that the Hall viscosity is surprisingly robust to disorder.

Formation and decay of eddy currents generated by crossed surface waves

31 May in 11:30

Parfenyev V.M., Filatov S.V., Brazhnikov M.Yu., Vergeles S.S., Levchenko A.A.

The mass-transport induced by crossed surface waves consists of the Stokes and Euler contributions which are very different in nature. The first contribution is a generalization of Stokes drift for a plane wave in ideal fluid and the second contribution arises due to the fluid viscosity and it is excited by a force applied in the viscous sublayer near the fluid surface. We study the formation and decay of the induced mass-transport theoretically and experimentally and demonstrate that both contributions have different time scales for typical experimental conditions. The evolution of the Euler contribution is described by a diffusion equation, where the fluid kinematic viscosity plays the role of the diffusion coefficient, while the Stokes contribution evolves faster, feeling the additional damping near the system boundaries. The difference becomes more pronounced if the fluid surface is contaminated. We model the effect of contamination by a thin insoluble liquid film presented on the fluid surface with the compression modulus being the only non-zero rheological parameter of the film. Then the Euler contribution into the mass-transport becomes parametrically larger and the evolution of the Stokes contribution becomes parametrically faster. The parameter is the same in both cases and it is equal to the quality factor of surfaces waves, which is modified by the presence of a surface film. We infer the value of the compression modulus of the film by fitting the results of transient measurements of eddy currents and demonstrate that the obtained value leads to the correct ratio of amplitudes of horizontal and vertical velocities of the wave motion and is in reasonable agreement with the measured dissipation rate of surface waves.

Bernoulli Experiment under Restart

31 May in 11:30

S. Belan

It is known that restart of the stochastic process can significantly reduce the expected time required to its completion. This effect is widely implemented to speed up the randomized search algorithms and can potentially be used to increase the rate of chemical reactions. However, complex stochastic processes often exhibit several possible scenarios of completion which are not equally desirable in terms of efficiency. In this talk I will discuss how restart affects the splitting probabilities of a Bernoulli-like stochastic process, i.e., of a process which can end with one of two outcomes. Special attention will be paid to the class of problems, where a carefully tuned restart rate maximizes the chances to obtain the desired outcome. Importantly, the analysis revealed universality displayed by the optimally restarted processes.

Spetsial’naya Kelerova geometriya i teorii Landau-Ginzburga

17 May in 11:30

Konstantin Aleshkin

Doklad po teme predstavlyaemoi k zashchite kandidatskoi dissertatsii.

Aspects of quarkonium propagation in a thermal medium as seen by string models

17 May in 11:30 (short)

Oleg Andreev

We use gauge/string duality to model a heavy quark-antiquark pair in a color singlet moving through a thermal plasma. In particular, we explore the effect of velocity on the string tension and Debye screening mass. Then we apply the results to the analysis of heavy quarkonium bound states. With some assumptions, we estimate the characteristic size of quarkonium and its dissociation temperature.

Realizatsiya fermionnykh modelei v sistemakh kholodnykh atomov

19 April in 11:30

S. I. Matveenko

Pokazano, chto topologicheskoe sverkhtekuchee sostoyanie s p-sparivaniem (p_x + i p_y) mozhet byt’ realizovano v dvumernoi opticheskoi reshetke fermionnykh polyarnykh molekul. Dlya sistem s odnosloinoi i dvukhsloinoi geometriei vychislennye temperatury fazovykh perekhodov v sverkhtekuchee sostoyanie okazalis’ eksperimental’no dostizhimymi, poryadka desyatkov nanokel’vinov. [A.K. Fedorov, S.I. Matveenko, V. I. Yudson, G.V. Shlyapnikov , "Novel p-wave superfluids of fermionic polar molecules", Sci. Rep. 6, 27448; (2016).]
Issledovana chislenno i analiticheski fazovaya diagramma dvusloinoi sistemy fermionnykh polyarnykh molekul s disbalansom molekulyarnykh plotnostei v sloyakh. Dlya disbalansa (effektivnogo magnitnogo polya), prevyshayushchego kriticheskoe znachenie, sistema perekhodit pri dostatochno nizkikh temperaturakh iz sostoyaniya odnorodnoi sverkhtekuchei zhidkosti v sostoyaniya Larkina-Ovchinnikova-Ful’de-Ferrella s periodicheskoi strukturoi parametra poryadka. V otlichie ot sluchaya kontaktnogo vzaimodeistviya s singletnym sparivaniem, dipol’-dipol’noe vzaimodeistvie generiruet nenulevuyu tripletnuyu sostavlyayushchuyu parametra poryadka. [Hao Lee, S. I. Matveenko, Daw-Wei Wang, G. V. Shlyapnikov, "Fulde-Ferrell-Larkin-Ovchinnikov state in bilayer dipolar systems", Phys.Rev. A, 96, 061602(R) (2017)].
Issledovana odnomernoi model’ dvukhkomponentnogo fermionnogo gaza s sil’nym kontaktnym ottalkivaniem chastits s protivopolozhnym spinom i nelokal’nym prityazheniem fermionov s odinakovym spinom. Model’ mozhet byt’ eksperimental’no realizovana v sisteme kholodnykh atomov. Pri etom parametry vzaimodeistviya mogut izmenyat’sya v shirokom diapazone s pomoshch’yu vneshnego magnitnogo polya. Ispol’zuya metody bozonizatsii i renormgruppy, naideno osnovnoe sostoyanie sistemy v zavisimosti ot parametrov vzaimodeistviya. Pokazano, chto pri kriticheskom znachenii nelokal’nogo vzaimodeistviya proiskhodit fazovyi perekhod pervogo roda v sostoyanie s nenulevoi namagnichennost’yu. [D. V. Kurlov, S. I. Matveenko, V. Gritsev, G. V. Shlyapnikov, "One-dimensional two-component fermions with contact even-wave repulsion and SU(2) breaking near-resonant odd-wave attraction", Phys. Rev. A, (prinyata v pechat’)].

Some exact solutions of the Volterra lattice

19 April in 11:30

V.E. Adler, A.B. Shabat

We study solutions of the Volterra lattice satisfying the stationary equation for its non-autonomous symmetry. It is shown that the dynamics in $t$ and $n$ are governed by the continuous and discrete Painlev\'e equations, respectively. The class of initial data leading to regular solutions is described. For the lattice on the half-line, these solutions are expressed in terms of the confluent hypergeometric function. The Hankel transform of the coefficients of the corresponding Taylor series is computed on the basis of the Wronskian representation of the solution.

CDD factors in integrable models perturbed by the current-current operators

29 March in 11:30

M. Lashkevich, Y. Pugai

F. Smirnov and A. Zamolodchikov in the paper published in 2016 showed that a special class of irrelevant perturbations (current-current perturbations) in integrable models of quantum field theory leads to appearance of CDD factors in the scattering matrices, i.e. scalar factors corresponding to non-uniqueness of solution to the Yang-Baxter equation for S matrices. They considered the sine-Gordon model and analogous models that only contain odd-spin integrals of motion. We find CDD factors (in the first order in the perturbation theory) for the current-current perturbations on the example of models that contain even-spin integrals of motion as well, the complex sinh-Gordon model and the scaling Z_N symmetric Ising model. Thus we generalize the Smirnov-Zamolodchikov formula to the case of several particles with diagonal scattering. We also obtain the CDD factors for Lorentz non-invariant perturbations of this type. Technically we use the representation by free fields for form factors, developed by us earlier.

Sud’ba oskolkov obrazovaniya Luny: geofizicheskie sledstviya Gigantskogo stolknoveniya

29 March in 11:30

A.V. Byalko, M.I. Kuz’min (Institut geokhimii SO RAN)

Naibolee veroyatnyi stsenarii obrazovaniya Luny daetsya raschetami Gigantskogo stolknoveniya (GS) ProtoZemli s protoplanetoi, po masse, blizkoi Marsu [1, 2]. Iskhodya iz vozrasta zemnykh i lunnykh tsirkonov, GS proizoshlo 4.4—4.5 mlrd. let nazad, na 160—170 mln let pozzhe vzryva Sverkhnovoi, zadavshego izotopnyi sostav Solnechnoi sistemy (SS). Pri GS na beskonechnost’ ukhodyat gazy i silikatnye oskolki s obshchei massoi poryadka 55-70% massy Luny. Odnako beskonechnost’ ubegayushchikh chastits est’ beskonechnost’ v zemnoi sisteme otscheta, v SS eti oskolki vykhodyat na konechnye orbity s periodami kak men’she, tak i bol’she goda. Vazhneishaya osobennost’ ikh orbit v tom, chto vse oni prokhodyat cherez uzkuyu oblast’ zemnoi orbity, gde proiskhodilo GS. Tam formiruetsya gazopylevoi struinyi potok, s zatukhayushchei intensivnost’yu on sushchestvuet menee milliona let. Chislennymi resheniyami zadachi trekh tel rasschitany mnogochislennye traektorii oskolkov. Otseneny veroyatnosti ikh stolknovenii s Zemlei i Lunoi v zavisimosti ot vremeni posle GS, a takzhe popadaniya v treugol’nye tochki Lagranzha L4 i L5. Rassmotreny geofizicheskie sledstviya etikh stolknovenii.

1.Canup R.M. & Asphaug E. Origin of the Moon in a giant impact near the end of the Earth's formation, Nature, 412, 208–212 (2001).
2.Canup R.M. Simulations of a late lunar-forming impact, Icarus 168, 433–456 (2004).

Studies of the Liquid Crystal Surface Anchoring Potential using Grandjean-Cano Wedge

22 March in 11:30 (short)

V.A. Belyakov

We extend further the theoretical and experimental studies of the actual surface anchoring potential restoration by polarization microscope technique and using micro-images in a wedge-shaped cell with weak surface anchoring forces filled by a chiral nematic liquid crystal (in Grandjean-Cano Wedge). To realize the theoretically predicted options of observation of large director deviation angles from the easy axes the experimental studies of director distribution in Grandjean-Cano zones were performed for differing easy axes orientations at the wedge surfaces in white light. A weak surface anchoring at one wedge surface was obtained by a photo-alignment technique. A strong surface anchoring at the second wedge surface was obtained by a rubbing. There were observed for the first time jump-less walls (without jumps of the director orientation) between neighboring Grandjean-Cano zones and jumps in color in the Newton's rings (lines) at the positions of the walls between Grandjean-Cano zones. Qualitative explanations of the both phenomena are presented and an expression for the jump in color value in the Newton's rings (lines) at the positions of the walls between Grandjean-Cano zones is presented. Some experimentally found by the polarization microscope and by the micro-photo technique images demonstrate jump-less walls between the first Grandjean-Cano zones. To ensure optimal parameters of the further experiments on the actual surface anchoring potential restoration theoretical calculations of the director distribution in individual Grandjean-Cano zones were performed for various model surface anchoring potentials. It was found that especially promising for description of the experimentally found director distribution looks the modified D-potential. As a result of the present studies the ways to enlarge (compared to the previous studies) angular range of the actual surface anchoring potential restoration were proposed.
(The presentation is based at the following papers: V.A. Belyakov, D.V. Shmeliova, S.V. Semenov, On the way of reconstruction of the liquid crystal surface anchoring potential Journal of Molecular Liquids 267, 151–157 (2018), С. В. Семенов, В. А. Беляков, ПОВЕРХНОСТНОЕ СЦЕПЛЕНИЕ И РАСПРЕДЕЛЕНИЕ ДИРЕКТОРА В КЛИНЕ ГРАНЖАНА–КАНО, ЖЭТФ, 2018, том 153, вып. 5, стр. 838–844 ( 2018), V.A.Belyakov , D.V.Shmeliova, and S.V. Semenov, Studies of the Liquid Crystal Surface Anchoring Potential using Grandjean-Cano Wedge, LIQUID CRYSTALS (Published online:

Obshchie osobennosti uglovykh diagramm provodimosti metallov v sil’nykh magnitnykh polyakh i slozhnost’ uglovykh diagrammakh magnitoprovodimosti v sil’nykh magnitnykh polyakh

22 March in 11:30

A.Ya. Maltsev

My rassmotrim samye obshchie osobennosti uglovykh diagramm provodimosti v normal’nykh metallakh so slozhnymi poverkhnostyami Fermi v prisutstvii sil’nykh magnitnykh polei. Opisanie takikh osobennostei budet osnovano na topologicheskom opisanii dinamicheskoi sistemy, voznikayushchei dlya evolyutsii elektronnykh sostoyanii na poverkhnosti Fermi v prisutstvii vneshnego magnitnogo polya. My rassmotrim uglovye diagrammy provodimosti dlya normal’nykh (monokristallicheskikh) metallov so slozhnymi poverkhnostyami Fermi v prisutstvii sil’nykh magnitnykh polei. Povedenie provodimosti v etom sluchae sil’no zavisit ot napravleniya magnitnogo polya i ustoichivye netrivial’nye rezhimy takogo povedeniya sootvetstvuyut pri etom spetsial’nym zonam ustoichivosti na uglovoi diagramme, otvechayushchim opredelennym (topologicheskim) svoistvam tenzora provodimosti. Kak my pokazhem, v obshchem sluchae mozhno razdelit’ takie diagrammy na dva obshchikh tipa, prostye (tip A) i slozhnye (tip B). Nas budut interesovat’ pri etom diagrammy vtorogo tipa, obladayushchie ryadom spetsificheskikh osobennostei (beskonechnoe chislo zon ustoichivosti, nalichie khaoticheskikh rezhimov i t.p.), kotorye my rassmotrim bolee podrobno. Po rezul’tatam rabot: ZhETF, t. 151, vyp. 5, 944-973 (2017); ZhETF, t. 152, vyp. 5(11), 1053-1064 (2017) , ZhETF, 154(6), 1183-1210 (2018)

Ergodic properties of dynamic systems on two-dimensional surfaces and electron transport phenomena in normal metals

22 March in 11:30 (short)

A.Ya. Maltsev, S.P. Novikov

V doklade obsuzhdaetsya svyaz’ spetsial’nykh kharakteristik dinamicheskikh sistem na poverkhnostyakh (indeksov Zoricha - Kontsevicha - Forni) s povedeniem provodimosti v metallakh v sil’nykh magnitnykh polyakh. Dannoe rassmotrenie yavlyaetsya vazhnym v sluchae vozniknoveniya naibolee slozhnykh (khaoticheskikh) elektronnykh traektorii na poverkhnosti Fermi, vozmozhnom dlya dostatochno slozhnykh poverkhnostei i spetsial’nykh napravlenii magnitnogo polya. Kak mozhno pokazat’, upomyanutye kharakteristiki imeyut neposredstvennoe otnoshenie k povedeniyu magnitoprovodimosti, takim obrazom, mozhno v printsipe govorit’ o vozmozhnosti ikh eksperimental’nogo opredeleniya v sootvetstvuyushchikh sluchayakh. Po rezul’tatam raboty: Trudy MIAN, tom 302, (2018) str. 296–315

SYK model with quadratic perturbations: the route to a non-Fermi-liquid

15 March in 11:30

A.V. Lunkin, K.S. Tikhonov, M.V. Feigel’man

Model’ SYK (Sachedev-Ye-Kitaev) opisyvaet sistemu sluchaino vzaimodeistvuyushchikh maioranovskikh fermionov bez kvadratichnykh chlenov v gamil’toniane. V predele bol’shogo chisla fermionov (N) i nizkikh temperaturakh (T « J, gde J - kharakternyi masshtab vzaimodeistviya) funktsiya Grina modeli, v sedlovom priblizhenii, imeet ne fermi-zhidkostnoe povedenie G(t) ~ t^(-1/2). Odnako, sedlovye uravneniya obladayut vysokoi simmetriei i dopuskayut zamenu t na proizvol’nuyu monotonnuyu funktsiyu f(t). Takoe reshenie imeet tol’ko SL(2,R) simmetriyu. Ponizhenie simmetrii ot polnoi gruppy reparametrizatsii do SL(2,R) privodit k sushchestovaniyu myagkoi mody, kotoraya stanovitsya sushchestvenna pri NT « J . Funktsiya Grina na samykh bol’shikh vremenakh menyaet svoyu asimptotiku na G(t) ~ t^(-3/2).
V nashei rabote my issleduem vliyanie kvadratichnogo vozmushcheniya na eto povedenie. Naivnoe rassmotrenie sedlovykh uravnenie pokazyvaet, chto na bol’shikh vremenakh fermi-zhidkostnoe povedenie dolzhno vosstanavlivat’sya. Odnako, voznikaet vopros: chto, proizoidyot esli eti vremena budut stol’ bol’shimi, chto nuzhno uchityvat’ fluktuatsii myagkoi mody? Rassmatrivaya vtoroi poryadok teorii vozmushcheniya my pokazyvaem, chto sushchestvuet nenulevoi interval amplitud vozmushchenii, kogda povedenie funktsii Grina ne menyaetsya, sokhranyaya asimptotiku G(t) ~ t^(-3/2). Eto pozvolyaet nadeyat’sya na ispol’zovanie modeli SYK dlya postroeniya kontroliruemoi teorii ne-fermizhidkostnogo povedeniya sil’no vzaimodeistvuyushchikh fermionov.

Boundary layer of elastic turbulence

15 March in 11:30 (short)

S. Belan, A. Chernykh, V. Lebedev

We consider the near-wall region in elastic turbulence of a dilute polymer solution in the limit of large Weissenberg number. As it was established experimentally, elastic turbulence possesses a boundary layer where the fluid velocity field can be approximated by a steady shear flow with relatively small fluctuations on the top of it. We examine analytically and numerically statistics of the polymer conformation in the boundary layer. An estimate for the ratio of the mean flow to the magnitude of flow fluctuations is obtained. This ratio is determined by the polymer concentration, the radius of gyration of polymers and their length in the fully extended state. The results of our asymptotic analysis reproduce the qualitative features of elastic turbulence at finite Weissenberg numbers.

XXXIV International Conference on Interaction of Intense Energy Fluxes with Matter, Elbrus-2019

15 March in 11:30 (short)

V.A. Khokhlov

Otchet ob uchastii v XXXIV Mezhdunarodnoi konferentsii po vzaimodeistviyu intensivnykh potokov energii s veshchestvom El’brus-2019

Physical processes during laser ablation into a liquid and during laser shock-wave pinning

15 March in 11:30 (short)

V.A. Khokhlov, N.A. Inogamov, V.V. Zhakhovsky,Yu.V. Petrov, S.I.Anisomov

The most important modern laser technologies include (1) the generation of colloid nanoparticles (NPs), laser ablation into a liquid (LAL—laser ablation in liquid) and (2) surface hardening of products by laser pinning (LSP—laser shock peening). Significantly, with laser pinning, the surface to be treated is washed with water. Therefore, the physics of processes during ablation into a liquid and during pinning is common. True, the accents are different. If the ablation in the liquid actually forget about the shock wave (SW) generated by the impact, and leaving the thickness of the target, in the problem with pinning, on the contrary, the main question is about the impact. In addition, the role of water in (1) and (2) is different. In (1) fluid contributes to the formation of NPs and adopts NPs, gently slowing them. Whereas in (2) water is needed to enhance the recoil and increase the amplitude of the hydrocarbon in the product. The complete picture, developed in the work, of course, should include both edges: and the formation of ejection into the liquid as a result of ablation—i.e. (1), observation of the SW wave from the nucleation stage to its attenuation in the product volume, i.e. (2).

Non-ergodic phase of the Quantum Random Energy Model

1 March in 11:30

L. Faoro, M. Feigel'man, L. Ioffe

Pokazano, chto fazovaya diagramma odnoi iz prosteishikh modelei kvantovogo spinovogo stekla – kvantovogo obobshcheniya modeli Derridy sluchainykh urovnei energii – obladaet neergodicheskoi delokalizovannoi fazoi s vremenem relaksatsii, eksponentsial’no dlinnym po chislu spinov n. Kak vremya relaksatsii, tak i ob’em Gil’bertova prostranstva, zanimaemyi mnogochastichnoi volnovoi funktsiei, yavlyayutsya stepennymi funktsiyami polnoi razmernosti Gil’bertova prostranstva N = 2^n. Oba eti pokazateli stepeni naideny v ramkakh priblizhennoi analiticheskoi teorii, poluchennye dlya nikh otvety neplokho soglasuyutsya s rezul’tatami pryamoi chislennoi diagonalizatsii. Poluchennye rezul’taty mogut byt’ polezny dlya fizicheskoi realizatsii kvantovogo simulyatora dlya resheniya zadach algoritmicheskoi optimizatsii tipa number partitioning.

Izuchenie sosushchestvovaniya faz v plenkakh smektikov v okrestnosti TKT dlya perekhoda geksatik - smektik A.

1 March in 11:30

V.V. Lebedev, E.S. Pikina , E.I. Kats

V rezul’tate teoreticheskogo analiza eksperimental’nykh dannykh po rasseyaniyu rentgenovkikh luchei na tonkikh svobodno podveshennykh plenkakh (SPP) zhidkogo kristalla 54COOBC vblizi fazovogo perekhoda smektik-A – geksatik ustanovleno, chto perekhod proiskhodit pervym rodom i vyyavlen temperaturnyi interval sosushchestvovaniya ukazannykh faz, kotoryi umen’shaetsya s umen’sheniem tolshchiny plenki. Eksperimental’nye dannye ob’yasnyayutsya blizost’yu sistemy k trikriticheskoi tochke (TKT). V ramkakh fenomenologicheskoi teorii fazovykh perekhodov Landau s vklyucheniem v rassmotrenie poverkhnostnykh effektov opredelena zavisimost’ shiriny dvukhfaznoi oblasti ot tolshchiny SPP v okrestnosti TKT. Analiticheskie raschety khorosho soglasuyutsya s rezul’tatami eksperimenta, i podtverzhdayut anomal’no glubokoe proniknovenie geksaticheskogo uporyadocheniya v SPP vblizi TKT. Zavisimost’ temperaturnogo intervala sosushchestvovaniya faz ot tolshchiny plenki svyazana s bol’shoi dlinoi korrelyatsii geksaticheskogo parametra poryadka. Poluchennye rezul’taty demonstriruyut unikal’nuyu vozmozhnost’ priblizheniya k trikriticheskoi tochke na linii fazovykh perekhodov smektik A - geksatik za schet izmeneniya tolshchiny plenki. Predlozhennyi podkhod mozhet byt’ primenen k shirokomu klassu sistem, obladayushchikh TKT.
Doklad osnovan na rabote: Evidence of a first-order smectic – hexatic transition and its proximity to tricritical point in smectic films., I.A. Zaluzhnyy, R.P. Kurta, N. Mukharamova, Y.Y. Kim, R.M. Khubbutdinov, D. Dzhigaev, V.V. Lebedev, E.S. Pikina, E.I. Kats, N.A. Clark, M. Sprung, B.I. Ostrovskii, I.A. Vartanyants, Phys. Rev. E, v. 98, p. 052703 (2018)

Laser technologies: science and applications

15 February in 11:30

N.A. Inogamov

In the first part of report the combined action of laser and plasmonic electromagnetic fields which dissipate in a metal film is considered. Fast dissipation of energy of light causes mechanical response moving a film. Motion and subsequent fast re-crystallization result in formation of surface micro-structures used for holographic purposes [1,2]. In the second part the physics of laser fragmentation of a liquid tin micro-droplet is analyzed. This is important for development of next generation of photo-lithography machines [3]. In the third part the indirect monitoring shot-to-shot shock waves strength reproducibility during the pump-probe experiments is studied [4]. The calibrated laser source is used after this checking for generation of shocks; goals for employing of these shocks are described in Albertazzi et al., Science Advances, 3(6), e1602705 (2017). [1] J. Phys.: Conf. Ser., 1092, 012051 (2018) [2] J. Phys.: Conf. Ser., 1092, 012052 (2018) [3] Phys. Rev. Applied 10, 064009 (2018) [4] J. Appl. Phys. 120, 035901 (2016)

Shock generation by laser and impact initiation of burning

15 February in 11:30

N.A. Inogamov

Generation of shocks by an ultrashort laser pulse is considered. Elastic-plastic response and polymorphic alpha-epsilon transition in iron are analyzed [1,2]. Initiation of initial stages of burning of high explosives by slow impact is studied [3]. Burning is caused by dissipative heating during plastic deformations.
[1] S.I. Ashitkov, V.V. Zhakhovsky, N.A. Inogamov, P.S. Komarov, M.B.Agranat, and G.I.Kanel, The behavior of iron under ultrafast shock loading driven by a femtosecond laser, AIP Conf. Proc. 1793, 100035 (2017) [2] V.V. Zhakhovsky, K.P. Migdal, N.A. Inogamov, S.I. Anisimov, MD simulation of steady shock-wave fronts with phase transition in single-crystal iron, AIP Conf. Proc. 1793, 070003 (2017) [3] D. Ilnitsky, N. Inogamov, V. Zhakhovsky, Response of explosive HMX to low-velocity impact: Modeling by the crystal plasticity finite element method, J. Phys.: Conf. Ser., 941, 012052 (2018)

Three-dimensional numerical simulation of long-lived quantum vortex knots and links in a trapped Bose-Einstein condensate

8 February in 11:30 (short)

V.P. Ruban

Dynamics of simplest vortex knots, unknots, and links of torus type inside an atomic Bose-Einstein condensate in anisotropic harmonic trap at zero temperature has been numerically simulated using three-dimensional Gross-Pitaevskii equation. The lifetime for such quasi-stationary rotating vortex structures has been found quite long in wide parametric domains of the system. This result is in qualitative agreement with a previous prediction based on a simplified one-dimensional model approximately describing dynamics of vortex filaments.


8 February in 11:30

V.G. Marikhin, A.V. Marikhina

One of us previously obtained and integrated the first examples of two-dimensional Schr¨odinger equations with a magnetic field belonging to the class of quasi–exactly solvable problems. It was shown that the wave functions are expressed in terms of degenerations of the Heun function: biconfluent and confluent Heun functions. Algebraic conditions were also found that determine the discrete spectrum and wave functions. Our goal here is to solve these algebraic equations numerically. In some cases, we can find an analytic approximation of the discrete spectrum.

Hermite quasi-polynomials

8 February in 11:30 (short)

V.G. Marikhin

The Hermite quasi-polynomials are obtained (the square root of the weight coincides with the Hermite one). The corresponding spectral problem with singularity at zero is constructed. The space to which belong the eigenfunctions of the above-mentioned spectral problem is constructed. The kind of this space solves the paradox with singularity.

Perkolyatsiya i dzhamming obraztsov sluchainoi posledovatel’noi adsorbtsii dlinnykh k-merov na kvadratnoi reshetke

8 February in 11:30 (short)

L.Yu. Barash

Pri pomoshchi komp’yuternogo modelirovaniya izuchayutsya perkolyatsionnyi perekhod i sostoyanie dzhamminga v modeli izotropnoi sluchainoi posledovatel’noi adsorbtsii. Razrabotan parallel’nyi algoritm, kotoryi ochen’ effektiven s tochki zreniya ego skorosti i ispol’zovaniya pamyati, i primenen k modeli sluchainoi posledovatel’noi adsorbtsii dlinnykh k-merov na kvadratnoi reshetke s periodicheskimi granichnymi usloviyami. Vychisleny porogovye plotnosti perkolyatsii i dzhamminga dlya dlin k-merov vplot’ do 131072. Ranee v literature takie vychisleniya provodilis’ tol’ko dlya k ≤ 512. Naiden rezhim povedeniya perkolyatsionnoi plotnosti dlya bol’shikh dlin chastits. Proanalizirovana struktura perkolyatsionnogo i dzhammingovogo sostoyanii. Teoreticheskie rezul’taty raboty [G. Kondrat et al., Phys. Rev. E 022154, 2017] obobshcheny na sluchai periodicheskikh granichnykh uslovii. Dokazano, chto lyuboi klaster v sostoyanii dzhamminga yavlyaetsya perkolyatsionnym klasterom, i chto perkolyatsiya voznikaet do dzhamminga.
Soobshchenie po rezul’tatam raboty M.G. Slutskii, L.Yu. Barash, Yu.Yu. Tarasevich, Percolation and jamming of random sequential adsorption samples of large linear k-mers on a square lattice, Phys. Rev. E 98, 062130 (2018).

On complex angular diagrams of magnetic conductivity in strong magnetic fields

1 February in 11:30 (short)

A.Ya. Maltsev

We consider angular conductivity diagrams for normal (single-crystal) metals with complex Fermi surfaces in the presence of strong magnetic fields. The behavior of conductivity in this case strongly depends on the direction of the magnetic field and the stable nontrivial regimes of this behavior correspond to special zones of stability on the angular diagram corresponding to certain (topological) properties of the conductivity tensor. As we show, in the general case such diagrams can be divided into two general types, simple (type A) and complex (type B). We will be interested in the diagrams of the second type, which have a number of specific features (an infinite number of stability zones, the presence of chaotic regimes, etc.), which we will consider in more detail.

Obshchie osobennosti uglovykh diagramm provodimosti metallov v sil’nykh magnitnykh polyakh.

1 February in 11:30 (short)

A.Ya. Mal’tsev

My rassmotrim samye obshchie osobennosti uglovykh diagramm provodimosti v normal’nykh metallakh so slozhnymi poverkhnostyami Fermi v prisutstvii sil’nykh magnitnykh polei. Opisanie takikh osobennostei budet osnovano na topologicheskom opisanii dinamicheskoi sistemy, voznikayushchei dlya evolyutsii elektronnykh sostoyanii na poverkhnosti Fermi v prisutstvii vneshnego magnitnogo polya.
Po rezul’tatam rabot: ZhETF, t. 151, vyp. 5, 944-973 (2017); ZhETF, t. 152, vyp. 5(11), 1053-1064 (2017)

JKLMR conjecture and Batyrev construction

1 February in 11:30

A. Belavin, A. Aleshkin, A. Litvinov

JKLMR gipoteza predpolagaet svyaz’ mezhdu tochnoi vychislennoi statsummoi nekotoroi Kalibrovochnoi supersimmetrichnoi Sigma-model’yu Vittena i Geometriei na prostranstve polei effektivnoi teorii polya, voznikayushchei v teorii Superstrun, kompaktifitsirovannoi na mnogoobrazie Kalabi-Yao. Ya rasskazhu o tom, kak ispol’zuya dual’nost’ mezhdu mnogrannikami Batyreva, ustanovit’ vysheukazannoe sootvetstvie tochno.
arXiv:1812.00478, submitted to Journal Statistical Physics

Ergodicheskie svoistva dinamicheskikh sistem na dvumernykh poverkhnostyakh i elektronnye transportnye yavleniya v normal’nykh metallakh

1 February in 11:30 (short)

A.Ya. Mal’tsev, S.P. Novikov

V doklade obsuzhdaetsya svyaz’ spetsial’nykh kharakteristik dinamicheskikh sistem na poverkhnostyakh (indeksov Zoricha - Kontsevicha - Forni) s povedeniem provodimosti v metallakh v sil’nykh magnitnykh polyakh. Dannoe rassmotrenie yavlyaetsya vazhnym v sluchae vozniknoveniya naibolee slozhnykh (khaoticheskikh) elektronnykh traektorii na poverkhnosti Fermi, vozmozhnom dlya dostatochno slozhnykh poverkhnostei i spetsial’nykh napravlenii magnitnogo polya. Kak mozhno pokazat’, upomyanutye kharakteristiki imeyut neposredstvennoe otnoshenie k povedeniyu magnitoprovodimosti, takim obrazom, mozhno v printsipe govorit’ o vozmozhnosti ikh eksperimental’nogo opredeleniya v sootvetstvuyushchikh sluchayakh.

1 February in 11:30

Pretsessiya spina zaryazhennoi chastitsy s MDM i EDM v gravitatsionnom pole Zemli

25 January in 11:30 (short)

S.N. Vergeles, N.N. Nikolaev

Vychislena uglovaya skorost’ pretsessii spina zaryazhennoi chastitsy s MDM i EDM v gravitatsionnom pole Zemli s uchyotom sutochnogo vrashcheniya. Khotya bol’shaya chast’ rezul’tata yavlyaetsya klassicheskoi i khorosho izvestnoi, vklad v pretsessiyu ot sutochnogo vrashcheniya do sikh por yavlyaetsya diskussionnym. Korrektnyi uchyot etogo vklada predstavlyaetsya neobkhodimym, tak kak eto vliyaet na pravil’nuyu traktovku eksperimentov po pretsessii spina v uskoritelyakh.

Generirovanie effektivnoi fermionnoi vershiny gravitatsionnym instantonom v reshetochnoi teorii gravitatsii

25 January in 11:30 (short)

S.N. Vergeles

Pokazano, chto v reshetochnoi gravitatsii, svyazannoi s fermionami, voznikayut effektivnye fermionnye vershiny. Eti vershiny generiruyutsya gravitatsionnymi instantonami, analogichno tomu kak voznikayut effektivnye fermionnye vershiny v teorii Yanga-Millsa vsledstvie nalichiya fermionnykh nulevykh mod, svyazannykh s instantonami.

Collinear photon emission from the quark-gluon plasma in heavy ion collisions

25 January in 11:30

B.G. Zakharov

Making use the light-cone path integral scheme we develop a formalism for collinear photon emission from the quark-gluon plasma (QGP) that accounts for accurately the Landau-Pomeranchuk-Migdal effect. In the case of the QGP without magnetic field we reproduce the AMY (Arnold, Moore, Yaffe (2001)) photon spectrum obtained within the thermal field theory. In the first part of the talk we study the role of running coupling and the effect of variation of the thermal quark mass on contribution of the collinear bremsstrahlung and quark-antiquark annihilation to photon emission in AA collisions in a scheme similar to that used in our previous jet quenching analyses. We find that for a scenario with the thermal quark mass about 50-100 MeV contribution of the higher order collinear processes summed with the 2 \to 2 processes can explain a considerable part (about 50%) of the experimental photon spectrum at k_T about 2-3 GeV for Au+Au collisions at $\sqrt{s}=0.2$ TeV. But for quark mass 300 MeV and for the thermal quark mass predicted by the hard thermal loop scheme the theoretical predictions underestimate considerably the experimental spectrum. In the second part of the talk we discuss a generalization of our formalism to the QGP with magnetic field. We then use it to investigate the effect of magnetic field on the photon emission from the QGP created in AA collisions. We find that even for very optimistic assumption on the magnitude of the magnetic field generated in AA collisions its effect on the photon emission rate is practically negligible. For this reason the magnetic field cannot generate a significant azimuthal asymmetry in the photon spectrum as it was suggested in the analysis by Tuchin (K. Tuchin, Phys. Rev. C{\bf 91}, 014902 (2015)).

Recent applications of the light-cone path integral formalism to the radiative effects in $AA$-collisions due to the induced gluon/photon emission in the QCD matter

18 January in 11:30

B.G. Zakharov

In this talk I discuss some recent applications of the light-cone path integral (LCPI) approach to the induced gluon/photon emission in the quark-gluon plasma (QGP) in $AA$-collisions at RHIC-LHC energies. I start with a brief discussion of the basic formulas of the LCPI formalism. Then I present the results for the nuclear modification of the photon-tagged jets in $AA$ collisions within the jet quenching scheme based on the LCPI approach to the induced gluon emission. The calculations are performed for running coupling. Collisional energy loss is treated as a perturbation to the radiative mechanism. We obtain a reasonable agreement with the recent data from the STAR Collaboration on the mid-rapidity nuclear modification factor $I_{AA}$ for Au+Au collisions at $\sqrt{s}=200$ GeV for parametrization of running $\alpha_s$ consistent with that necessary for description of the data on suppression of the high-$p_T$ spectra. The main part of the talk will be devoted to the radiative contribution to the jet $p_T$-broadening in the QGP. For the first time the analysis of the radiative $p_T$-broadening of a fast quark in the QGP is performed accounting for the real and virtual two-parton states beyond the soft gluon approximation. It is shown that radiative processes can strongly suppress the radiative $p_T$-broadening in the QCD matter (and even make it negative). This prediction is qualitatively different from the results of previous analyses in th soft gluon approximation in the double logarithmic approximation (B. Wu, JHEP 1110, 029 (2011); T. Liou, A. H. Mueller and B. Wu, Nucl. Phys. A916, 102 (2013); J.-P. Blaizot and Y. Mehtar-Tani, Nucl. Phys. A929, 202 (2014)) predicting that radiative processes should significantly increase $p_T$-broadening. Our prediction is consistent with the recent data of the STAR Collaboration (L. Adamczyk et al., Phys.Rev. C96, 024905 (2017)), which do not show any signal of $p_T$-broadening in Au+Au collisions at the energy 200 GeV. At the end of the talk I discuss the the role of running coupling and the effect of variation of the thermal quark mass on contribution of the collinear bremsstrahlung and annihilation to photon emission in $AA$ collisions in a scheme similar to that used in our previous jet quenching analyses.

Inelastic neutron scattering as a confirmation of a new type of gapped surface excitations in liquid helium

18 January in 11:30 (short)

P.D. Grigoriev, A.D. Grigoriev, A.M. Dyugaev

We analyze the experimental data on inelastic neutron scattering by a thin ~5-atomic-layer film of liquid helium at three different temperatures: T=0.4K, 0.98K and 1.3K. The neutron scattering intensity plots, in addition to the previously know dispersion of phonons and ripplons, suggest a branch of gapped surface excitations with activation energy ~4.5K and the dispersion similar to that expected for surfons -- the bound quantum states of helium atoms above liquid helium surface, proposed and investigated theoretically. These data, probably, provide the first direct experimental confirmation of surfons. Before these surface excitations received only indirect experimental substantiation, based on the temperature dependence of surface tension coefficient and on their interaction with surface electrons. The existence of surfons as an additional type of surface excitations, although being debated yet, is very important for various physical properties of He surface. We also analyze previous numerical results on excitations in liquid helium and argue that surface excitations similar to surfons have been previously obtained by numerical calculations and called resonance interface states.

Linear magnetoresistance in the charge density wave state of quasi-two-dimensional rare-earth tritellurides

18 January in 11:30 (short)

P.D. Grigoriev

The magnetoresistance of a TbTe3 two-dimensional conductor with a charge-density wave (CDW) has been measured in a wide temperature range and in magnetic fields of up to 17 T. At temperatures well below the Peierls transition temperature and in high magnetic fields, the magnetoresistance exhibits a linear dependence on the magnetic field caused by the scattering of normal charge carriers by “hot” spots of the Fermi surface. In the sliding CDW regime in low magnetic fields, a qualitative change in the magnetoresistance has been observed associated with the strong scattering of carriers by the sliding CDW.
[1] A.V. Frolov, A.P. Orlov, P.D. Grigoriev, V.N. Zverev, A.A. Sinchenko, P. Monceau, Magnetoresistance of a Two-Dimensional TbTe3 Conductor in the Sliding Charge-Density Wave Regime, JETP Lett., 107(8), 488-492 (2018)

Dual description of integrable sigma-models

11 January in 11:30

Litvinov Alexey

In my talk I will discuss an example of the weak / strong coupling duality, i.e. equivalence seemingly distinct quantum field theories, so that the strong coupling regime of one theory describes the weak coupling regime of the other, and vice versa. In my example, these are two-dimensional sigma models and boson field theories with exponential interaction. Both theories are integrable. To explain the duality, I will construct a W-algebra commuting with a set of screening operators on one side and solve the Ricci flow equation with given ultraviolet asymptotic boundary conditions.
The report is based joint work with Fateev and Spodyneiko.

Deautonomization of cluster integrable systems

11 January in 11:30

M. Bershtein

Cluster integrable systems have a combinatorial definition in terms of counting dimer configurations on a bipartite graph on a torus. They have a large group of discrete symmetries preserving the Hamiltonian. After deautonomization, the Hamiltonians depend on time, integrability disappears, and discrete symmetry leads to remarkable difference equations, such as the Painleve equations. These equations are solved using the partition functions of five-dimensional supersymmetric theories. The talk is based on joint work with P. Gavrilenko and A. Marshakov.

Elektronnye svoistva neuporyadochenogo grafena

28 December 2018 in 11:30

Pavel Ostrovskii

Doklad po predstavlyaemoi k zashchite doktorskoi dissertatsii.

On the initial conditions in heavy ion collisions at RHIC and LHC energies

21 December 2018 in 11:30 (short)

B.G. Zakharov

We discuss our recent results on the heavy ion collisions at RHIC and LHC energies. We discuss the initial conditions for the entropy distribution in AA-collisions within the Glauber Monte-Carlo model accounting for the effect of the meson-baryon components in the nucleon light-cone wave function. Also, we discuss fluctuations of the electromagnetic fields produced in the non-central AA-collisions in the classical and quantum picture. We show that quantum calculations based on the fluctuation-dissipation theorem give fluctuations of the electromagnetic field that are much smaller than that in the classical Monte-Carlo calculations with the Woods-Saxon nuclear density widely used in the literature.

Quantum corrections to conductivity of disordered electrons due to inelastic scattering off magnetic impurities

21 December 2018 in 11:30

I.S. Burmistrov

We study the quantum corrections to the conductivity of the two-dimensional disordered interacting electron system in the diffusive regime due to inelastic scattering off rare magnetic impurities. We focus on the case of very different g factors for electrons and magnetic impurities. Within the Born approximation for the inelastic scattering off magnetic impurities we find additional temperature-dependent corrections to the conductivity of the Altshuler-Aronov type.
The talk is based on I. S. Burmistrov and E. V. Repin, Phys. Rev. B 98, 045414 (2018)

Magnetism of Bi2Se3 thin films with Eu-rich flat inclusions

21 December 2018 in 11:30 (short)

I.S. Burmistrov

I report about theoretical support of experimental data on the measurement of the magnetic properties of thin films of bismuth selenide doped with europium atoms, which form flat inclusions. The magnitudes of the various mechanisms of magnetic ordering are theoretically estimated. The estimates obtained are in satisfactory agreement with the experimental data.
Report is based on the paper: L.N. Oveshnikov, Ya.I. Rodionov, K.I. Kugel, I.A. Karateev, A.L. Vasiliev, Yu.G. Selivanov, E.G. Chizhevskii, I.S. Burmistrov and B.A. Aronzon, "Magnetism of Bi2Se3 Thin Films with Eu-rich flat inclusions", J. Phys .: Condens. Matter 30, 445801 (2018)

Volterra chain and Catalan numbers

21 December 2018 in 11:30 (short)

V.E. Adler, A.B. Shabat

The model problem on the decay of a step for the Volterra chain is formulated as a Cauchy problem with initial condition equal to 0 in one node and 1 in the others. We show that this problem admits an exact solution in terms of the Bessel functions. The Taylor series arising here are related to the exponential generating function for Catalan numbers. Asymptotic formulas for the solution are obtained.

Two-sphere partition functions and Kahler potentials on CY moduli spaces

14 December 2018 in 11:30 (short)

A. Belavin, K. Aleshkin, A. Litvinov

We study the relation between exact partition functions of gauged $N=(2,2)$ linear sigma-models on $S^{2}$ and K\"ahler potentials of CY manifolds proposed by Jockers et all. We suggest to use a mirror version of this relation. For a class of manifolds given by a Fermat hypersurfaces in weighted projective space we check the relation by explicit calculation.
Aleshkin K., Belavin A., Litvinov A., “Two-sphere partition functions and Kähler potentials on CY moduli spaces”, Письма в ЖЭТФ, 108(10), 725 (2018)

Probing spin susceptibility of a correlated two-dimensional electron system by transport and magnetization measurements

14 December 2018 in 11:30 (short)

I.S. Burmistrov

I report theoretical support of the data on measuring the spin susceptibility at different temperatures and electron concentrations in a two-dimensional electron system based on a silicon field-effect transistor in the group of V.M. Pudalov (Lebedev Institute).
The short talk is based on the work of V. M. Pudalov, A. Yu. Kuntsevich, M.E. Gershenson, I.S. Burmistrov, and M. Reznikov, Phys. Rev. B 98, 155109 (2018).

A thermally driven spin-transfer-torque system far from equilibrium: enhancement of the thermoelectric current via pumping current

14 December 2018 in 11:30

I.S. Burmistrov

We consider a small itinerant ferromagnet exposed to an external magnetic field and strongly driven by a thermally induced spin current. For this model, we derive the quasi-classical equations of motion for the magnetization where the effects of a dynamical non-equilibrium distribution function are taken into account self-consistently. We obtain the Landau-Lifshitz-Gilbert equation supplemented by a spin-transfer torque term of Slonczewski form. We identify a regime of persistent precessions in which we find an enhancement of the thermoelectric current by the pumping current.
The talk is based on T. Ludwig, I.S. Burmistrov, Y. Gefen, A. Shnirman, "A thermally driven spin-transfer-torque system far from equilibrium: enhancement of the thermoelectric current via pumping current", arxiv:1808.01192

Mesoscopic supercurrent fluctuations in diffusive magnetic Josephson junctions

23 November 2018 in 11:30

P. A. Ioselevich, P. M. Ostrovsky, Ya. V. Fominov

We study the supercurrent in quasi-one-dimensional Josephson junctions with a weak link involving magnetism, either via magnetic impurities or via ferromagnetism. In the case of weak links longer than the magnetic pair-breaking length, the Josephson effect is dominated by mesoscopic fluctuations. We establish the supercurrent-phase relation (CPR) along with statistics of its sample-dependent properties in junctions with transparent contacts between leads and link. High transparency gives rise to the inverse proximity effect, while the direct proximity effect is suppressed by magnetism in the link. We find that all harmonics are present in the CPR. Each harmonic has its own sample-dependent amplitude and phase shift with no correlation between different harmonics. Depending on the type of magnetic weak link, the system can realize a \varphi_0 or \varphi junction in the fluctuational regime. Full supercurrent statistics is obtained at arbitrary relation between temperature, superconducting gap, and the Thouless energy of the weak link.

Statistics of eigenstates near the localization transition on random regular graphs

23 November 2018 in 11:30

Konstantin Tikhonov

Dynamical and spatial correlations of eigenfunctions as well as energy level correlations in the Anderson model on random regular graphs (RRG) are studied. We consider the critical point of the Anderson transition and the delocalized phase. In the delocalized phase near the transition point, the observables show a broad critical regime for system sizes below the correlation volume and then cross over to the ergodic behavior. Eigenstate correlations allow us to visualize the correlation length that controls the finite-size scaling near the transition. The critical-to-ergodic crossover is very peculiar, since the critical point is similar to the localized phase, whereas the ergodic regime is characterized by very fast diffusion which is similar to the ballistic transport. In particular, the return probability crosses over from a logarithmically slow variation with time in the critical regime to an exponentially fast decay in the ergodic regime. We find a perfect agreement between results of exact diagonalization and those resulting from the solution of the self-consistency equation obtained within the saddle-point analysis of the effective supersymmetric action. We show that the RRG model can be viewed as an intricate limit of the Anderson model in spatial dimensions.

Poverkhnostnyi impedans na diffuznoi granitse kiral’nogo p-volnovogo sverkhprovodnika

16 November 2018 in 11:30

Ya.V. Fominov

Vychislena lokal’naya kompleksnaya provodimost’ i obuslovlennyi eyu poverkhnostnyi impedans na diffuznoi granitse kiral’nogo p-volnovogo sverkhprovodnika. Imenno kiral’noe p-volnovoe sostoyanie schitaetsya naibolee veroyatnym v sverkhprovodyashchem rutenate strontsiya Sr2RuO4. Ono anizotropnoe i pri etom polnost’yu shchelevoe (modul’ parametra poryadka fiksirovan, a faza zavisit ot napravleniya). My rassmatrivaem otklik na vneshnee elektromagnitnoe pole kak na podshchelevykh, tak i na nadshchelevykh chastotakh. Izucheny anomal’nye osobennosti poverkhnostnogo impedansa, svyazannye s generatsiei vblizi granitsy nechyotnykh po chastote sverkhprovodyashchikh korrelyatsii (sostoyanie tipa sverkhprovodimosti Berezinskogo). Teoreticheskie rezul’taty sopostavleny s izmereniyami poverkhnostnogo impedansa Sr2RuO4, provedyonnymi v IFTT. Nablyudaetsya kachestvennoe soglasie teorii i eksperimenta.
Doklad osnovan na rabote S. V. Bakurskiy, Ya. V. Fominov, A. F. Shevchun, Y. Asano, Y. Tanaka, M. Yu. Kupriyanov, A. A. Golubov, M. R. Trunin, H. Kashiwaya, S. Kashiwaya, and Y. Maeno, "Local impedance on a rough surface of a chiral p-wave superconductor", Phys. Rev. B 98, 134508 (2018);

Sverkhprovodyashchii spinovyi klapan v sistemakh so splavom Geislera

16 November 2018 in 11:30 (short)

Ya.V. Fominov

Provedeno teoreticheskoe soprovozhdenie eksperimentov po izmereniyu effekta sverkhprovodyashchego spinovogo klapana v sisteme tipa FFS (gde F — ferromagnetik, S — sverkhprovodnik). Effekt sostoit v tom, chto kriticheskaya temperatura Tc sistemy zavisit ot vzaimnoi orientatsii namagnichennostei dvukh ferromagnetikov. V eksperimente v kachestve srednego F sloya byl vzyat splav Geislera Co2Cr1-xFexAl, i eto pozvolilo usilit’ effekt (raznost’ Tc pri parallel’noi i antiparallel’noi orientatsii) po sravneniyu s ranee issledovannymi sistemami s zhelezom. Znak effekta zavisit ot tolshchiny sloya. Teoriya ob’yasnyaet poluchennye rezul’taty. Usilenie effekta okazyvaetsya svyazano s umen’shennoi velichinoi obmennogo polya v splave Geislera.
Doklad osnovan na sleduyushchikh rabotakh:
[1] A. Kamashev, A. Validov, N. Garif’yanov, Ya. Fominov, P. Leksin, J. Schumann, J. Thomas, V. Kataev, B. Büchner, I. Garifullin, "Isolation of proximity-induced triplet pairing channel in a superconductor/ferromagnet spin valve", EPJ Web of Conferences 185, 08001 (2018).
[2] A.A. Kamashev, A.A. Validov, J. Schumann, V. Kataev, B. Büchner, Ya.V. Fominov, I.A. Garifullin, "Increasing the performance of a superconducting spin valve using a Heusler alloy", Beilstein J. Nanotechnol. 9, 1764 (2018).

New integrals of motion for waves on the deep water with a free surface

16 November 2018 in 11:30 (short)

A.I. Dyachenko

Khorosho izvestno, chto v priblizhenii slaboi nelineinosti dlya voln na vode (teoriya slaboi turbulentnosti), kogda uchityvayutsya tol’ko chetyrekh-volnovye vzaimodeistviya, imeetsya integral dvizheniya - polnoe "chislo voln" (volnovoe deistvie). Volny na glubokoi vode mogut byt’ razdeleny na dve gruppy, begushchie vlevo i begushchie vpravo. Pokazano, chto osobye svoistva koeffitsienta chetyrekh-volnovogo vzaimodeistviya privodyat k sokhraneniyu ne tol’ko polnogo "chisla voln", no i dvukh novykh integralov dvizheniya: "chislo voln", begushchikh vlevo, i "chislo voln", begushchikh vpravo.

Two-temperature statistics of free energies in (1+1) directed polymers

2 November 2018 in 11:30

Victor Dotsenko

The joint statistical properties of two free energies computed at two different temperatures in the same sample of (1+1) directed polymers is studied in terms of the replica technique. The scaling dependence of the free energies differenceon the two temperatures $T_{1}$ and $T_{2}$ is derived. In particular, it is shown that if the two temperatures $T_{1} < T_{2}$ are close to each other the typical value of the fluctuating part of the free energies difference is proportional to $(1 - T_{1}/T_{2})^{1/3}$. It is also shown that the left tail asymptotics of this free energy difference probability distribution function coincides with the corresponding tail of the Tracy-Widom distribution.
Europhysics Letters, 116, 40004 (2016); arXiv:1703.04305

Non-Born effects in scattering of electrons in clean quasi-one-dimensional conductors

26 October 2018 in 11:30

A. S. Ioselevich, N. S. Peshcherenko

Quasi-one-dimensional systems demonstrate Van Hove singularities in the density of states $\nu_F$ and the resistivity $\rho$, occurring when the Fermi level $E$ crosses a bottom $E_N$ of some subband of transverse quantization. We demonstrate that the character of smearing of the singularities crucially depends on the concentration of impurities. There is a crossover concentration $n_c\propto |\lambda|$, $\lambda\ll 1$ being the dimensionless amplitude of scattering. For $n\gg n_c$ the singularities are simply rounded at $\varepsilon\equiv E-E_N\sim \tau^{-1}$ – the Born scattering rate. For $n\ll n_c$ the non-Born effects in scattering become essential, despite $\lambda\ll 1$. The peak of the resistivity is split: for $\varepsilon>0$ there is a broad maximum at $\varepsilon\propto \lambda^2$. For $\varepsilon\lt 0$ there is a deep minimum at $|\varepsilon|\propto n^2\ll \lambda^2$. The behaviour of $\rho$ below the minimum depends on the sign of $\lambda$. In case of repulsion $\rho$ monotonically grows with $|\varepsilon|$ and saturates for $|\varepsilon| \gg \lambda^2$. In case of attraction $\rho$ has sharp maximum at $|\varepsilon| \propto \lambda^2$. The latter feature is due to resonant scattering by quasistationary bound states that inevitably arise just below the bottom of each subband for any attracting impurity.

Electron-phonon cooling power in Anderson insulators

26 October 2018 in 11:30

M. V. Feigel'man, V. E. Kravtsov

A theory for electron-phonon energy exchange in Anderson insulators with long localization length is developed. The major contribution to the cooling power as a function of electron temperature is shown to be directly related to the correlation function of the local density of electron states, which is enhanced near the localization transition by multi-fractality and by the presence of Mott's resonant pairs of states. The theory we develop explains huge enhancement of the cooling power observed in insulating Indium Oxide films as compared to predictions of standard theory for disordered metals

The free field representation for the GL(1|1) WZW model revisited

12 October 2018 in 11:30

M. Lashkevich

The Wess—Zumino—Witten theory related to the GL(1|1) supergroup possesses some interesting features. On one hand, its structure is rather simple, but, on the other hand, it is an example of a so called logarithmic theory, i.e. a conformal field theory that contains fields whose correlation functions depend on distances logarithmically. The spectrum of conformal dimensions in this theory is continuous, and logarithmic operators appear at some degenerate points, including those of zero dimension. The free field representation is an effective tool to study models of the conformal field theory, and that of the GL(1|1) theory seems to be rather simple and well-studied in previous works. Nevertheless, on my opinion, not all advantages of this representation were used. In the present work, beside a more detailed calculation of the structure constants, the fusion and braiding matrices were studied. It was shown that in the vicinity of degenerate points it is possible to chose a basis of conformal blocks, which resolves degeneration. I show how this basis is related to the logarithmic operators of the theory.

Quantum electrodynamics of heavy ions and atoms

5 October 2018 in 11:30

Vladimir Shabaev (St. Petersburg State University)

The present status of the QED theory of heavy ions and atoms is reviewed. The theoretical predictions for the Lamb shifts, the hyperfine splittings, and the bound-electron g factors of highly charged few-electron ions are compared with available experimental data. Special attention is paid to tests of QED at strong-coupling regime and determination of fundamental constants. The current status of studying the parity nonconservation effects with heavy atoms is also reported. Recent results on the charge-transfer and pair-creation probabilities in low-energy heavy-ion collisions are presented. Prospects for tests of QED at supercritical fields are discussed.

Irreversible Markov chains: From the TASEP to all-atom Coulomb computations

28 September 2018 in 15:00

Werner Krauth, Ecole normale supérieure, Paris (France)

The Markov chain Monte Carlo method traditionally consists in exploring large configuration spaces using a reversible random walk where moves are accepted or rejected based on an energy criterion. In this talk, I will present recent progress on irreversible Markov chains that challenge this picture. In one-dimensional particle systems, the new algorithms are related to the TASEP (totally asymmetric simple exclusion model). We can rigorously prove that they mix on much shorter time scales than the reversible Metropolis algorithms. I will then show how these algorithms sample the Boltzmann distribution (and thus explore configuration space) without computing the energy. In long-range interacting systems, where the computation of the energy is time-consuming, this provides a key advantage for the new method. For locally charge-neutral systems in three dimensions, we obtain a highly efficient algorithm, of N log N complexity in the number N of particles. I discuss the main paradox of this method: How is it possible to sample the Boltzmann distribution without computing the energy, and then review some recent successes as well as prospects and challenges for irreversible Markov chains in statistical physics.
S. C. Kapfer, W. Krauth, Physical Review Letters 119, 240603 (2017)
Z. Lei, W. Krauth, arXiv:1806.06786 (2018)
M. F. Faulkner, L. Qin, A. C. Maggs, W. Krauth, arXiv:1804.05795 (2018)

Superconductivity that breaks time-reversal symmetry and its experimental manifestations

28 September 2018 in 11:30

Victor Yakovenko (University of Maryland)

Since 2006, it has been found experimentally that superconductivity spontaneously breaks time-reversal symmetry (TRS) in certain materials, such as Sr2RuO4, UPt3, URu2Si2, and Bi/Ni bilayers. In the latter case, we argue that the superconducting order parameter has the winding number of +-2 around the Fermi surface, thus making Bi/Ni bilayers a rare example of intrinsic 2D topological superconductivity [1]. The experimental evidence for TRS breaking comes from the polar Kerr effect, which is rotation of polarization of normally incident light upon reflection from the sample. Theoretical studies indicate that this effect is possible only if a superconductor has more than one band. To clarify these conditions, we study a model of chiral TRS-breaking superconductivity on the honeycomb lattice [2]. We consider superconducting pairing on the neighboring sites belonging to different sublattices. The matrix of this superconducting pairing is non-unitary and does not commute with the normal-state Hamiltonian. We find that the latter condition is necessary for experimental manifestations of the TRS breaking. We show that such superconducting pairing generates persistent loop currents around each lattice site and opens a topological mass gap at the Dirac points with the corresponding chiral edge states, as in Haldane's model of the quantum anomalous Hall effect. We calculate the intrinsic ac Hall conductivity in the absence of an external magnetic field, which determines the polar Kerr effect, and show that it is proportional to the loop-current order parameter.
[1] X. Gong, M. Kargarian, A. Stern, D. Yue, H. Zhou, X. Jin, V. M. Galitski, V. M. Yakovenko, and J. Xia, Science Advances 3, e1602579 (2017), arXiv:1609.08538
[2] P. M. R. Brydon, D. S. L. Abergel, D. F. Agterberg, and V. M. Yakovenko, arXiv:1802.02280

Three-dimensional stability of leapfrogging quantum vortex rings

21 September 2018 in 11:30 (short)

V.P. Ruban

It is shown by numerical simulations within a regularized Biot-Savart law that dynamical systems of two or three leapfrogging coaxial quantum vortex rings having a core width $\xi$ and initially placed near a torus of radii $R_0$ and $r_0$, can be three-dimensionally (quasi-)stable in some regions of parameters $\Lambda=\ln(R_0/\xi)$ and $W=r_0/R_0$. At fixed $\Lambda$, stable bands on $W$ are intervals between non-overlapping main parametric resonances for different (integer) azimuthal wave numbers $m$. The stable intervals are most wide ($\Delta W\sim$ 0.01--0.05) between $m$-pairs $(1,2)$ and $(2,3)$ at $\Lambda\approx$ 4--12 thus corresponding to micro/mesoscopic sizes of vortex rings in the case of superfluid $^4$He. With four and more rings, at least for $W>0.1$, resonances overlap for all $\Lambda$ and no stable domains exist.

About application for FRBF-a grant

14 September 2018 in 11:30 (short)

S.S. Vergeles

Report on application for RFBR-a grant. The project topic is "Theory elaboration for coherent vortices in a three-dimensional fluid."

Synchronization of Conservative Parallel Discrete Event Simulations on a Small-World Network

7 September 2018 in 11:30

Lev N. Shchur и Liliia Ziganurova

We examine the question of the influence of sparse long-range communications on the synchronization in parallel discrete event simulations (PDES). We build a model of the evolution of local virtual times (LVT) in a conservative algorithm including several choices of local links. All network realizations belong to the small-world network class. We find that synchronization depends on the average shortest path of the network. The time profile dynamics are similar to the surface profile growth, which helps to analyze synchronization effects using a statistical physics approach. Without long-range links of the nodes, the model belongs to the universality class of the Kardar–Parisi–Zhang equation for surface growth. We find that the critical exponents depend logarithmically on the fraction of long-range links. We present the results of simulations and discuss our observations.
L. Ziganurova, L.N. Shchur, Synchronization of Conservative Parallel Discrete Event Simulations on a Small-World Network, Phys. Rev. E 98, 022218 (2018); arXiv:1807.04463

Quantum Many-Body Physics of Qubits

22 June 2018 in 11:30

L. Glazman (Yale University)

The ongoing development of superconducting qubits has brought some basic questions of many-body physics to the research forefront, and in some cases helped solving them. I will address two effects in quantum condensed matter highlighted by the development of a fluxonium qubit. The first one is the so-called cosine-phi problem stemming from the seminal paper of Brian Josephson: the predicted there phase dependence of the dissipative current across a Josephson junction was observed in a fluxonium, after nearly 50 years of unsuccessful attempts by other techniques. The second one is the dynamics of a weakly-pinned charge density wave: we predict that the dynamics may be revealed in measurements of microwave reflection off a superinductor, which is a key element of the fluxonium.

Lazernoe vozdeistvie na veshchestvo: sovremennoe sostoyanie

15 June 2018 in 11:30

Anisimov S.I., Inogamov N.A., Petrov Yu.P., Khokhlov V.A.

V doklade aktsentiruetsya vnimanie na sravnenii rezhimov oblucheniya s raznoi dlitel’nost’yu impul’sa. V odnom sluchae eto ul’trakorotkie lazernye impul’sy (UkLI), v drugom subnanosekundnye. Ul’trakorotkimi nazyvayut impul’sy prodolzhitel’nost’yu poryadka pikosekund i koroche, t.e. i 2 ps, i 10 fs - eto UkLI. Rech’ idet o vozdeistvii na metall cherez prozrachnuyu sredu. Prozrachnaya sreda mozhet byt’ tverdoi, a mozhet byt’ zhidkoi. Ponyatno, chto energetika takogo vozdeistviya ogranichena, poskol’ku neobkhodimo izbegat’ razvitogo opticheskogo proboya prozrachnoi sredy - takoi proboi otsekaet lazernoe izluchenie ot metallicheskoi misheni. Zadacha imeet vazhnye prilozheniya v fizike lazernoi ablyatsii v zhidkost’, ablyatsii, soprovozhdayushcheisya generatsiei nanochastits i formirovaniem kolloidov. Eto burno rastushchee nauchno-tekhnologicheskoe napravlenie, ob’edinyayushchee fiziku lazernogo vozdeistviya i khimiyu protsessov mezhdu produktami ablyatsii i zhidkost’yu, predstavlennuyu rastvorami solei ili organiki. Vo vtoroi chasti doklada daetsya obzor rezul’tatov, poluchennykh za poslednie dva goda. Razlichnye razdely raboty vypolneny v sootvetstvii s goszadaniem i po grantam RNF (14-19-01599) i RFFI (16-02-00864, 16-08-01181).

Dynamics of Poles in 2D Hydrodynamics with Free Surface: New Constants of Motion

8 June 2018 in 11:30

A. I. Dyachenko, S. A. Dyachenko, P. M. Lushnikov and V. E. Zakharov

We consider Euler equations for potential flow of ideal incompressible fluid with a free surface and infinite depth in two dimensional geometry. We admit a presence of gravity forces and surface tension. A time-dependent conformal mapping z(w,t) of the lower complex half-plane of the variable w into the area filled with fluid is performed with the real line of w mapped into the free fluid's surface. We study the dynamics of singularities of both z(w,t) and the complex fluid potential Pi(w,t) in the upper complex half-plane of w. We show the existence of solutions with an arbitrary finite number N of simple complex poles in z_w(w,t) and Pi_w(w,t) which are the derivatives of z(w,t) and Pi(w,t) over w. These poles are often coupled with branch points located at other points of the upper half-plane of w. We find that the residues of the simple poles of z_w(w,t) are new, previously unknown constants of motion, provided surface tension is zero. All these constants of motion commute with each other in the sense of underlying Hamiltonian dynamics. In absence of both gravity and surface tension, the residues of simple poles of Pi_w(w,t) are also the constants of motion. For nonzero gravity and zero surface tension, the residues of poles of any order of Pi_w(w,t) are the trivial linear functions of time. Nonzero surface tension allows residues of poles of even order to be compatible with the fluid dynamics. We also found solutions with N higher order poles. In all above cases the number of independent real integrals of motion is 4N for zero gravity and 4N-1 for nonzero gravity. We suggest that the existence of these nontrivial constants of motion provides an argument in support of the conjecture of complete integrability of free surface hydrodynamics in deep water.
A.I. Dyachenko, S.A. Dyachenko, P.M. Lushnikov, V.E. Zakharov, Dynamics of Poles in 2D Hydrodynamics with Free Surface: New Constants of Motion, Journal of Fluid Mechanics, submitted (2018); arXiv:1809.09584.

Spetsial’naya geometriya v strunnykh kompaktifikatsiyakh i kiral’nye algebry

1 June 2018 in 11:30

Konstantin Aleshkin, A. Belavin

V doklade ya planiruyu izlozhit’ nedavnie uspekhi v vychislenii geometrii prostranstv modulei mnogoobrazii Kalabi-Yau, neobkhodimykh dlya opisaniya nizkoenergetichnogo predela teorii strun. Nami byli polucheny obshchie formuly dlya normalizatsii konstant svyazi nizkoenergetichnoi teorii (spetsial’naya geometriya). A imenno, ispol’zuya svyaz’ s kiral’nymi algebrami, my napisali yavnye formuly v vide ryadov dlya spetsial’noi geometrii dlya klassov mnogoobrazii Kalabi-Yau tipa Ferma.
K. Aleshkin, A. Belavin, Exact computation of the Special geometry for Calabi-Yau hypersurfaces of Fermat type , Pis’ma v ZhETF, 108(10), 723-724 (2018)

Razmernost’ fraktal’nogo interfeisa v prostranstvennoi zadache dilemmy uznika.

25 May 2018 in 11:30

L.N. Shchur

V poslednie dvadtsat’ let polucheno mnogo rezul’tatov po klassifikatsii kriticheskogo povedeniya dvumernykh sistem na osnove kriticheskogo povedeniya interfeisov. Nezavisimo ot razvitiya etoi nauki (Evolyutsiya Shrama-Levnera), poyavilis’ utverzhdeniya, osnovannye na chislennom modelirovanii, o tom, chto protekanie v nekotorykh statisticheskikh sistemakh demonstriruet svoistva, tipichnye dlya fazovogo perekhoda pervogo roda. My issledovali geometricheskie svoistva interfeisov v zadache, kotoraya osnovana na klassicheskoi zadache iz teorii igr, zadache dilemmy uznika. V issleduemoi nami modeli igroki raspolagayutsya v uzlakh kvadratnoi reshetki. Kazhdyi igrok na kazhdom shage po vremeni mozhet menyat’ svoyu strategiyu v zavisimosti ot ego okruzheniya. V opredelennom diapazone parametra podscheta vybora strategii takaya deterministicheskaya dinamika privodit k kvazi-statsionarnomu rezhimu, s chetko vyrazhennoi strukturoi. Struktura sostoit iz dvukh tipov klasterov, ravnoi chislu vozmozhnykh strategii. Eti klastery imeyut konechnuyu massu, to est’ ikh razmernost’ ravna dvum. V sluchae perekhoda pervogo roda, dlina granitsy klastera rastet lineino s razmerom sistemy. V sluchae perekhoda vtorogo roda, dlina granitsy rastet bystree lineinoi, no medlennee, chem ploshchad’. V nashem sluchae, okazalos’, chto asimptoticheski razmernost’ interfeisa rastet kvadratichno. Eto dovol’no neozhidannyi rezul’tat. Izvestno, chto regulyarnye fraktaly mogut imet’ razmernost’ 2. Dlya sluchainykh fraktalov takoi sluchai ranee byl neizvesten.

World population and climate variations

11 May 2018 in 11:30

Alexey Byalko

Few sets of the world population data are analyzed from 1 AD to 2015 together with temperature variations of the North Hemisphere from 1 AD to 1979. Possible data errors are evaluated. Hyperbolical behavior of the world population was evaluated by approximation of its inverse function. The population index is introduced as the relative difference between inverse numerical data and its parabolic approximation. The index occurs to be a bounded and an average zero function with the nearly uniform error level. He describes relative variations of the world population in the past. The population index is compared with North Hemisphere temperature variations. However, the population response to temperature variations occurred with a significant delay of about 100 years. Possible reasons for such a correlation are discussed against the background of known historical events and analyzed by the Hurst method. The historical analysis and the found climate—population correlations give a principal possibility to forecast the world population behavior approximately up to year 2080.

Eukaryotic cell polarity and protein sorting

27 April 2018 in 11:30

Andrea Gamba, Politecnico di Torino

I will review some of the biophysical processes that allow eukaryotic cells to break their native symmetry and polarize in order to provide adequate responses to signals and properly adapt to the environment. An essential part of the process is the incessant spatial reorganization of membrane-bound proteins due to the action of reinforcing biochemical feedback loops that contrast the homogenizing effect of diffusion. A second component is the coupling of protein and lipid dynamics: protein crowding induces the bending of lipid membranes and the nucleation of small lipid vesicles enriched in specific molecular factors destined to be targeted to appropriate destinations. This mechanism leads to an incessant distillation process controlled by the strength of protein-protein interactions. A phenomenological theory of the process can be developed, predicting the existence of an optimal distillation regime characterized by simple scaling laws. Experiments suggest that living cells work close to this optimal regime, likely as the result of evolutionary pressure.

Dielectric response of Anderson and pseudogapped insulators

27 April 2018 in 11:30

M.V. Feigel'man, D.A. Ivanov, E. Cuevas

Using a combination of analytic and numerical methods, we study the polarizability of a (non-interacting) Anderson insulator in one, two, and three dimensions and demonstrate that, in a wide range of parameters, it scales proportionally to the square of the localization length, contrary to earlier claims based on the effective-medium approximation. We further analyze the effect of electron-electron interactions on the dielectric constant in quasi-1D, quasi-2D and 3D materials with large localization length, including both Coulomb repulsion and phonon-mediated attraction. The phonon-mediated attraction (in the pseudogapped state on the insulating side of the Superconductor-Insulator Transition) produces a correction to the dielectric constant, which may be detected from a linear response of a dielectric constant to an external magnetic field.
M.V. Feigel’man, D.A. Ivanov, E. Cuevas, Dielectric response of Anderson and pseudogapped insulators, New J. Phys. 20, 053045 (2018); arXiv:1711.05972

Some Aspects of Diquarks as seen by String Theory

20 April 2018 in 11:30

Oleg Andreev

I will discuss a few aspects of diquarks in QCD from the viewpoint of a 5-dimensional effective string theory.

Magnetic oscillations of in-plane conductivity in quasi-two-dimensional metals

13 April 2018 in 11:30

Pavel Grigor’ev

We develop the theory of transverse magnetoresistance in layered quasi-two-dimensional metals. Using the Kubo formula and harmonic expansion we calculate intralayer conductivity in a magnetic field perpendicular to conducting layers. The analytical expressions for the amplitudes and phases of magnetic quantum oscillations (MQO) and of the so-called slow oscillations (SlO) are derived and applied to analyze their behavior as a function of several parameters: magnetic field strength, interlayer transfer integral and the Landau-level width. Both the MQO and SlO of intralayer and interlayer conductivity have approximately opposite phase in weak magnetic field and the same phase in strong field. The amplitude of SlO of intralayer conductivity changes sign at $\omega_c\tau\approx\sqrt{3}$. There are several other qualitative differences between magnetic oscillations of in-plane and out-of-plane conductivity. The results obtained are useful to analyze experimental data on magnetoresistance oscillations in various strongly anisotropic quasi-2D metals.

Long-lived quantum vortex knots

6 April 2018 in 11:30

V.P. Ruban

In the bulk of a superfluid, besides well-known and experimentally observed quantum vortex rings, theoretically there can exist (developing in time) also solitary topologically non-trivial excitations as vortex knots [1-3]. The simplest of them are torus knots ${\cal T}_{p,q}$, where $p$ and $q$ are co-prime integers, while parameters of torus are the toroidal (large) radius $R_0$ and the poloidal (small) radius $r_0$, both sizes being large in comparison with a width of quantum vortex core $\xi$. It was believed on the basis of previously obtained numerical results that such knots are unstable and they reconnect during just a few typical times, traveling a distance of several $R_0$ (the lifetime is somewhat longer for smaller ratios $B_0=r_0/R_0$). The mentioned results were obtained for not too large ratios $R_0/\xi\lesssim 20$, and with a very coarse step (about 0.1) on parameter $B_0$. In this work it was numerically found that actually the situation is much more complicated and interesting. The dynamics of trefoil knot ${\cal T}_{2,3}$ was accurately simulated within a regularized Biot-Savart law using a small step on $B_0$. At fixed values of parameter $\Lambda=\log(R_0/\xi)$, the dependence of knot lifetime on parameter $B_0$ turned out to be drastically non-monotonic on sufficiently small $B_0\lesssim 0.2$. Moreover, at $\Lambda\gtrsim 3$ quasi-stability bands appear, where vortex knot remains nearly unchanged for many dozens and even hundreds of typical times [4]. Qualitatively similar results take place also for ${\cal T}_{3,2}$ [4], for some other knots (${\cal T}_{2,5}$, ${\cal T}_{2,7}$, ${\cal T}_{3,4}$, ${\cal T}_{3,5}$, ${\cal T}_{3,7}$), and for unknots ${\cal U}_{2,1}$ [5]. These observations essentially enrich our knowledge about dynamics of vortex filaments.
References: [1] D. Proment, M. Onorato, and C. F. Barenghi, "Vortex knots in a Bose-Einstein condensate", Phys. Rev. E 85, 036306 (2012).
[2] D. Proment, M. Onorato, and C. F. Barenghi, "Torus quantum vortex knots in the Gross-Pitaevskii model for Bose-Einstein condensates", J. Phys.: Conf. Ser. 544, 012022, (2014).
[3] D. Kleckner, L. H. Kauffman, and W. T. M. Irvine, "How superfluid vortex knots untie", Nature Physics 12, 650 (2016).
[4] Ruban V.P., "Dolgozhivushchie kvantovye vikhrevye uzly", Pis’ma v ZhETF, 107 (5), 325-328 (2018).
[5] V. P. Ruban, unpublished.

Dynamic phase transition in rare events statistics of 1D KPZ problem

30 March 2018 in 11:30

Alex Kamenev (University of Minnesota)

I will review the concept of non-equilibrium phase transitions in rare events statistics as well as a recent dramatic progress in studies of 1D KPZ. The focus of my talk is on the reflection symmetry breaking phase transition recently found stationary KPZ problem:

Chiral magnetic crystals

23 March 2018 in 11:30

Markus Garst (TU Dresden)

The weak Dzyaloshinskii-Moriya interaction in chiral cubic magnets like MnSi, FeGe or Cu2OSeO3 twists the magnetization on long length scales resulting in spatially periodic magnetic textures — magnetic crystals. There exist especially magnetic crystals with a one- and two-dimensional periodicity corresponding to the magnetic helix and the topologically non-trivial skyrmion lattice, respectively. In this talk, we provide an overview of their properties. In particular, we discuss the crystallization process of these magnetic crystals that is characterized by strongly correlated chiral paramagnons that drive the transition first-order [1,2]. This fluctuation-induced first-order transition is well described by a theory put forward by Brazovskii. We will introduce the magnon band structure and their non-reciprocal properties in the presence of a magnetic field [3,4]. For the skyrmion lattice, this band structure is topological and characterized by finite Chern numbers that can be attributed to the formation of magnon Landau levels due to an emergent orbital magnetic field [5,6,7]. Finally, we will discuss domain walls of helimagnets that share similarities with grain boundaries consisting of disclination and dislocation defects of the helimagnetic order [8]. References: [1] M. Janoschek et al. Phys. Rev. B 87, 134407 (2013). [2] A. Bauer, M. Garst and C. Pfleiderer, Phys. Rev. Lett. 110, 177207 (2013). [3] M. Kugler et al. Phys. Rev. Lett. 115, 097203 (2015) [4] T. Weber et al. arXiv:1708.02098 [5] C. Schütte and M. Garst, Phys. Rev. B 90, 094423 (2014). [6] T. Schwarze, J. Waizner, M. Garst, A. Bauer, I. Stasinopoulos, H. Berger, C. Pfleiderer, and D. Grundler, Nat. Mater. 14, 478 (2015). [7] M. Garst J. Waizner, and D. Grundler, J. Phys. D: Appl. Phys. 50, 293002 (2017) [8] P. Schoenherr et al. Nat. Phys. in press, arXiv:1704.06288

Universality in statistics of Stokes flow over no-slip wall with random roughness

16 March 2018 in 11:30

V. Parfenyev, S. Belan, and V. Lebedev

Stochastic roughness is widespread feature of natural surfaces and is an inherent by-product of most fabrication techniques. In view of rapid development of microfluidics, the important question is how this inevitable evil affects the low-Reynolds flows which are common for micro-devices. Moreover, one could potentially turn the flaw into a virtue and control the flow properties by means of specially "tuned" random roughness. We investigate theoretically the statistics of fluctuations in fluid velocity produced by the waviness irregularities at the surface of a no-slip wall. Particular emphasis is laid on the issue of the universality of our findings.

Spinovoe ekho v nakopitel’nykh kol’tsakh

2 March 2018 in 11:30

N. Nikolaev, F. Ratmann, F. Saleev

Sinkhrotronnye (prodol’nye) kolebaniya v banchirovannykh nakoplennykh puchkakh privodyat k razbrosu chastot pretsessii spina v nakopitele. Pri usrednenii po ansamblyu chastits eto privodit k zatukhanii vynuzhdennykh rezonansnym radiochastotnym rotatorom spina kolebanii polyarizatsii chastits. Budet pokazano, chto pri slaboi, no konechnoi otstroike chastoty rotatora (my rassmotrim radiochastotnyi fil’tr Vina) ot chastoty svobodnoi pretsessii spina v uderzhivayushchem magnitnom pole nakopitelya, voznikaet rezhim svoeobraznogo spinovogo ekha: ogibayushchaya vynuzhdennykh kolebanii ubyvaet vnachale po stepennomu zakonu, zatem amplituda polnost’yu vosstanavlivaetsya, i protsess povtoryaetsya periodicheski. Eto kur’yoznoe nablyudenie mozhet imet’ prakticheskoe prilozhenie k poiskam rezonansnogo vrashcheniya EDM zaryazhennykh chastits v nakopitelyakh.

Matritsy Kartana v teorii tsepochek Toda-Darbu

2 March 2018 in 11:30

A. Shabat, V. Adler

Obsuzhdaetsya vzaimno odnoznachnoe sootvetstvie polinomial’nykh pervykh integralov gamil’tonovykh sistem s eksponentsial’nym vzaimodeistviem i “giper-integralov” dvumerizovannoi tsepochki Tody. Ustanovleny formuly pereschyota sootvetstvuyushchikh mnogochlenov i nekotorye obshchie svoistva ikh algebraicheskoi struktury.

Povtornoe poyavlenie anomal’nykh voln v optike.

16 February 2018 in 11:30

P.G. Grinevich, P.M. Santini

Ya khotel by rasskazat’ o nashei rabote s eksperimentatorami iz Rimskogo universiteta o nablyudenii povtornoi generatsii anomal’noi volny v opticheskom kristalle.
D. Pierangeli, M. Flammini, L. Zhang, G. Marcucci, A.J. Agranat, P.G. Grinevich, P.M. Santini, C. Conti, E. DelRe, Observation of Fermi-Pasta-Ulam-Tsingou Recurrence and Its Exact Dynamics, Phys. Rev. X 8, 041017 (2018)

Manufacturing of holes in supported films: transition from beam dependent to shock dependent radius of hole as absorbed energy increases

9 February 2018 in 11:30

N. Inogamov, V. Shepelev, P. Danilov, A. Kuchmizhak

Thin films on supporting substrates are important class of laser targets for surface nanomodification for, e.g., plasmonic or sensoric applications. There are many papers devoted to this problem. But all of them are concentrated on dynamics of a film, paying small attention to substrate. In those papers the substrate is just an object absorbing the first shock. Here we present another point of view directed namely onto dynamics of a substrate. We consider (i) generation of a shock wave (SW) in a supporting substrate, (this si generation by impact of a film/support contact on supporting condensed medium); (ii) transition from 1D to 2D propagation of SW; (iii) we analyze lateral propagation of the SW along a film/support contact; and (iv) we calculate pressure in the compressed layer behind the SW decaying with time. This positive pressure acting from substrate to the film accelerates the film in direction to vacuum. Above some threshold, velocity of accelerated film is enough to separate the film from support. In the cases with large energy absorbed by a film, the circle of separation is significantly wider than the circle of high heating around the focal laser spot on film surface. Absorbed laser heat exponentially decays around an irradiated spot $F = Fc\, exp(-r^2/RL^2)$, where RL is radius of laser Gaussian beam. While the law of decay for the 2D SW in substrate is the power law. Therefore in the mentioned cases of powerful laser action, the edge of a separation circle is driven by SW in support.
Illustrative materials are posted on youtube:

Video 1
This movie shows the map of evolution of density field. The gold film is the narrow horizontal strip, "vacuum" is above, supporting substrate is below the strip

Video 2
This is the pressure map. We see two shocks: one above and second below the film. Don't pay attention to the shock above, i.e. to shock in "vacuum", because in our simulation we cannot use real vacuum rho=0, p=0. Therefore we use low density media in place of vacuum. Pay attention to the left and right wings of crescent type shock propagating down. These wings pass along the film. Shock pressure in the wings accelerate the film up thus separating it from the silica substrate.


Differential Poisson's ratio of a crystalline two-dimensional membrane

26 January 2018 in 11:30

I.S. Burmistrov

We compute analytically the differential Poisson's ratio of a suspended two-dimensional crystalline membrane embedded into a space of large dimensionality $d \gg 1$. We demonstrate that, in the regime of anomalous Hooke's law, the differential Poisson's ratio approaches a universal value determined solely by the spatial dimensionality $d_c$, with a power-law expansion $\nu = -1/3 + 0.016/d_c + O(1/d_c^2)$, where $d_c=d-2$. Thus, the value $-1/3$ predicted in previous literature holds only in the limit $d_c\to \infty$.

Mesoscopic Stoner instability: Suppression by tunneling to a reservoir

19 January 2018 in 11:30

I.S. Burmistrov

We derive the generalized Ambegaokar-Eckern-Schon action which governs the dynamics of the charge and spin degrees of freedom for the quantum dot described by the universal Hamiltonian and tunnel coupled to a reservoir. Contrary to previous works, we derive this dissipative action without the following assumptions (i) the absolute value of the spin is not a ected by the tunneling coupling to a reservoir and (ii) the spin rotates slowly such that the adiabatic approximation holds. We use the derived dissipative action for analysis of stability of the mesoscopic Stoner phenomenon with respect to the electron tunneling to a reservoir. We nd that at nite temperature the electron tunneling suppresses the mesoscopic Stoner instability at tunneling conductance which depends on temperature. At zero temperature we predict the existence of the quantum phase transition between the mesoscopic Stoner phase and the paramagnetic phase.

Exact solutions for nonlinear development of Kelvin-Helmholtz instability for counterflow of superfluid and normal components of Helium II

22 December 2017 in 11:30

Pavel M. Lushnikov and Nikolay M. Zubarev

A relative motion of the normal and superfluid components of Helium II results in Kelvin-Helmholtz instability (KHI) at their common free surface. We found the exact solutions for the nonlinear stage of the development of that instability. Contrary to the usual KHI of the interface between two fluids, the dynamics of Helium II free surface allows decoupling of the governing equations with their reduction to the Laplace growth equation which has the infinite number of exact solutions including the formation of sharp cusps at free surface in a finite time.

Poverkhnostnye mikrochastitsy v zhidkom gelii. Kvantovyi zakon Arkhimeda

15 December 2017 in 11:30

А.М. Дюгаев

Issledovany otkloneniya ot zakona Arkhimeda dlya sfericheskikh chastits radiusa R0, vypolnennykh iz molekulyarnogo vodoroda u poverkhnosti zhidkogo He4. Klassicheskii zakon Arkhimeda imeet mesto, esli R0 bol’she kapillyarnoi dliny geliya Lk ≅ 500 µm. Pri etom velichina vozvysheniya chastitsy nad zhidkost’yu h+ ~ R0. V oblasti 30 < R0 < 500 µm sila Arkhimeda podavlyaetsya siloi poverkhnostnogo natyazheniya i h+~ R03⁄Lk2. Pri R0 < 30 µm chastitsa nakhoditsya pod poverkhnost’yu zhidkosti. Zdes’ sila Arkhimeda konkuriruet s siloi Kazimira, kotoraya ottalkivaet chastitsu ot poverkhnosti vglub’ zhidkosti. Rasstoyanie chastitsy do poverkhnosti h- ~ Rs5⁄3⁄R02⁄3, esli R0 > Rs. Zdes’ Rs – masshtab, nabrannyi, v osnovnom, iz mirovykh postoyannykh, Rs ≈ (ℏc/ϱg)1⁄5 ≈ 1µm. (ℏ - postoyannaya Planka, c - skorost’ sveta, g – uskorenie svobodnogo padeniya, ϱHe – plotnost’ geliya). Dlya ochen’ malen’kikh chastits ( R0 < Rs) rasstoyanie do poverkhnosti zhidkosti h- ne zavisit ot ikh razmera h- = Rs.

Medlennye ostsillyatsii magnitosoprotivleniya v vysokotemperaturnykh sverkhprovodnikakh YBCO: ikh chastota daet ploshchad’ karmanov poverkhnosti Fermi ili velichinu mezhsloevogo pereskoka elektronov

15 December 2017 in 11:30

P.D. Grigor’ev

Nablyudaemye magnitnykh kvantovye ostsillyatsii (MKO) v vysokotemperaturnykh sverkhprovodnikakh YBCO (YBa2Cu3O6 +x i YBa2Cu4O8) imeyut dovol’no neobychnyi sostav garmonik. Preobrazovanie Fur’e etikh MKO soderzhit tri blizkikh ravnoudalennykh pika pri dostatochno nizkikh chastotakh ~530T i 530+-90T, chto sootvetstvuet okolo 2% zony Brillyuena, prichem tsentral’nyi pik imeet amplitudu v ~2 raza vyshe, chem dva pika s kazhdoi iz storon. Obshcheprinyatoe ob’yasnenie takikh kvantovykh ostsillyatsii predpolagaet perestroiku iskhodnoi bol’shoi poverkhnosti Fermi iz-za fluktuiruyushchei volny zaryadovoi plotnosti (VZP). Odnako takoe ob’yasnenie imeet ryad sushchestvennykh nedostatkov. Naprimer, ono predpolagaet takzhe nabor drugikh blizkikh chastot MKO, kotorye ne nablyudayutsya eksperimental’no. Krome etogo, v etoi modeli nablyudaemye chastoty MKO dolzhny sil’no zaviset’ ot urovnya dopirovaniya, chto takzhe ne nablyudaetsya v eksperimente. My predlagaem al’ternativnuyu interpretatsiyu nablyudaemykh magnitnykh ostsillyatsii v YBCO, kotoraya dovol’no estestvennym obrazom ob’yasnyaet nablyudaemuyu kartinu bez dopolnitel’nykh podgonochnykh parametrov. Eta predlagaemaya model’ MKO uchityvaet dvukhsloinuyu kristallicheskuyu strukturu YBCO i vklyuchaet sootvetstvuyushchee rasshcheplenie elektronnogo spektra i dispersiyu elektronov perpendikulyarno provodyashchim sloyam. Pri etom osnovnaya nablyudaemaya chastota ~530T sootvetstvuet velichine bisloinogo rasshchepleniya, a ne malomu karmanu poverkhnosti Fermi (PF), vyzvannomu ee perestroikoi iz-za VZP. Takie "medlennye" magnitnye ostsillyatsii poyavlyayutsya dazhe bez perestroiki PF i pochti ne zavisyat ot urovnya dopirovaniya. Krome togo, v otlichie ot obychnykh MKO, eti "medlennye" ostsillyatsii ne podavlyayutsya dlinnovolnovoi prostranstvennoi neodnorodnost’yu obraztsa, tipichnoi dlya VTSP kristallov i privodyashchei k razmytiyu urovnya Fermi vdol’ obraztsa. Poetomu oni legche nablyudayutsya v eksperimente. Predlozhennaya interpretatsiya pozvolyaet razreshit’ «protivorechie» dannykh ARPES i MKO, a takzhe ob’yasnyaet nekotorye drugie osobennosti nablyudaemykh MKO v YBCO, kotorye dovol’no slozhno ob’yasnit’ stsenariem perestroiki PF vyzvannoi VZP.

Effektivizatsiya konechnozonnykh formul, opisyvayushchikh modulyatsionnuyu nestabil’nost’ v Nelineinom uravnenii Shredingera - sluchai N neustoichivykh mod.

8 December 2017 in 11:30

P.G. Grinevich, P.M. Santini

Dlya sluchaya proizvol’nogo chisla neustoichivykh mod my yavno s tochnost’yu do popravok vysshego poryadka vychislyaem vse velichiny, vkhodyashchie v konechnozonnye resheniya, chto privodit k otvetu v elementarnykh funktsiyakh (raznomu dlya raznykh oblastei x,t-ploskosti).

Optimizatsiya algoritma otzhiga populyatsii

1 December 2017 in 11:30

L.Yu. Barash, M. Weigel, M. Borovský, W. Janke, L.N. Shchur

Otzhig populyatsii (population annealing) -- perspektivnyi metod dlya raschetov Monte-Karlo v statisticheskoi fizike, v tom chisle, dlya modelirovaniya sistem so slozhnymi energeticheskimi landshaftami. Metod yavlyaetsya gibridnym, on kombiniruet vyborku po znachimosti pri pomoshchi markovskikh tsepei s elementami posledovatel’nogo Monte-Karlo v forme kontrolya populyatsii. Khotya on predostavlyaet algoritmicheskie vozmozhnosti dlya raschetov takikh sistem, kotorye na pervyi vzglyad sravnimy s vozmozhnostyami bolee izvestnykh i shiroko ispol’zuemykh metodov, takikh kak parallel’naya zakalka (parallel tempering), metod otzhiga populyatsii namnogo luchshe podkhodit dlya massivno parallel’nykh vychislenii. My detal’no analiziruem eto strukturnoe preimushchestvo i predstavlyaem optimizirovannuyu realizatsiyu otzhiga populyatsii dlya graficheskikh protsessorov, kotoraya imeet na neskol’ko poryadkov bolee vysokuyu proizvoditel’nost’ po sravneniyu s posledovatel’noi realizatsiei na CPU. Effektivnost’ primeneniya optimizirovannogo algoritma detal’no proanalizirovana dlya dvumernoi ferromagnitnoi modeli Izinga. V to zhe vremya, algoritm mozhet byt’ legko adaptirovan dlya modelirovaniya drugikh spinovykh modelei, vklyuchaya neuporyadochennye sistemy. Takzhe, my predlagaem i analiziruem neskol’ko novykh usovershenstvovanii, znachitel’no uvelichivayushchikh effektivnost’ algoritma, takikh kak adaptivnye shagi po temperature i mul’ti-gistogrammnyi analiz dannykh.

Nonlinear Schrodinger Equation for standing water waves

24 November 2017 in 11:30

A.I. Dyachenko

Helical edge transport in the presence of anisotropic magnetic impurity

17 November 2017 in 11:30

P. D. Kurilovich, V. D. Kurilovich, I. S. Burmistrov, M. Goldstein

We consider the effects of electron scattering on a quantum magnetic impurity on the current-voltage characteristics of the helical edge of a two-dimensional topological insulator. We compute the backscattering contribution to the current along the edge for a general form of the exchange interaction matrix and arbitrary value of the magnetic impurity spin. We find that the differential conductance might be a non-monotonous function of the voltage with several extrema. Effects of magnetic anisotropy for the impurity are considered.

Explicit computation of the Calabi-Yau moduli space geometry

10 November 2017 in 11:30

K. Aleshkin, A. Belavin

Knowledge of the CY moduli space geometry is crucial to determine Low energy Lagranzhian in superstring compactifications. For hypersurfaces in projective spaces explicit computations were done only in a few cases. In the talk I will explain a recently proposed method, which allows to perform explicit computations easily and in the more general cases. I'l show how to apply this method to computation the 101-dimensional moduli space of Quintic threefold .

Strogoe dokazatel’stvo sushchestvovaniya samodual’nogo resheniya (instantona) v reshetochnoi teorii gravitatsii, a takzhe fermionnoi nulevoi mody, assotsiirovannoi s instantonom

3 November 2017 in 11:30

S.N. Vergeles

Strogo dokazyvaetsya, chto v reshetochnoi modeli gravitatsii, predlozhennoi Vergelesom i izuchennoi v ryade rabot, sushchestvuet avtodual’noe reshenie, t.e. instanton. Reshetochnyi instanton sushchestvuet v prostranstve, topologicheski ekvivalentnom chetyrekhmernomu evklidovu prostranstvu. Dokazyvaetsya takzhe, chto sushchestvuet fermionnaya nulevaya moda, assotsiirovannaya s reshetochnym instantonom.

Cooper pair splitting in ballistic ferromagnetic SQUIDs

27 October 2017 in 11:30

P.L. Stroganov, Ya.V. Fominov

We consider ballistic SQUIDs with spin filtering inside half-metallic ferromagnetic arms. A singlet Cooper pair cannot pass through an arm in this case, so the Josephson current is entirely due to the Cooper pair splitting, with two electrons going to different interferometer arms. In order to elucidate the mechanisms of Josephson transport due to split Cooper pairs, we assume the arms to be single-channel wires in the short-junction limit. Different geometries of the system (determined by the length of the arms and the phases acquired by quasiparticles during splitting between the arms) lead to qualitatively different behavior of the SQUID characteristics (the Andreev levels, the current-phase relation, and the critical Josephson current) as a function of two control parameters, the external magnetic flux and misorientation of the two spin filters. The current-phase relation can change its amplitude and shape, in particular, turning to a pi-junction form or acquiring additional zero crossings. The critical current can become a nonmonotonic function of the misorientation of the spin filters and the magnetic flux (on half of period). Periodicity with respect to the magnetic flux is doubled, in comparison to conventional SQUIDs.

Mikrovolnovye svoistva sverkhprovodnikov vblizi perekhoda v izolyator

20 October 2017 in 11:30

L. Ioffe. M. Feigel’man

Predlozhena osnova teorii kollektivnykh mod v sil’no neuporyadochennykh sverkhprovodnikakh, nakhodyashchikhsya vblizi kvantovogo perekhoda v dielektricheskoe sostoyanie. Pokazano, chto s priblizheniem parametrov sverkhprovodnika k kvantovoi kriticheskoi tochke, v spektre vozbuzhdenii s neizbezhnost’yu voznikaet nenulevaya plotnost’ nizkolezhashchikh (s energiyami sushchestvenno nizhe sverkhprovodyashchei shcheli) sostoyanii. Pri eshche bol’shem besporyadke eti podshchelevye sostoyaniya okazyvayutsya delokalizovannymi, chto dolzhno privodit’ k zametnoi dissipatsii v mikrovolnovom otklike.

Out-of-equilibrium statistical physics of optimization and learning

13 October 2017 in 11:30

Riccardo Zecchina (Bocconi University)

The extraction of information from large amounts of data is one of the prominent cross disciplinary challenges in contemporary science. Solving optimization and learning problems over large scale data sets requires the design of efficient algorithms over very large scale networks of constraints. These problems can be viewed as minimization problems over very complex energy landscapes, for which out-of-equilibrium phenomena of the type studied in statistical physics of disordered systems often play a crucial role. In this talk I will give a brief overview of the main conceptual advances, and I will discuss some recent results which provide both sharp predictions on the theory underlying the most advanced Machine Learning techniques and novel algorithms. I will conclude by describing a serendipitous mathematical connection between the novel algorithms and quantum annealing, and I will give concrete examples of quantum vs thermal exponential speed up.

Paraconductivity of pseudogapped superconductors

6 October 2017 in 11:30

Igor Poboiko and Mikhail Feigel'man

We calculate Aslamazov-Larkin paraconductity for a model of strongly disordered superconductors (dimensions d=2,3) with a large pseudogap whose magnitude strongly exceeds transition temperature Tc. We show that, within Gaussian approximation over Cooper-pair fluctuations, paraconductivity is just twice larger that the classical AL result at the same ε = (T-Tc)/Tc. Upon decreasing ε, Gaussian approximation is violated due to local fluctuations of pairing fields that become relevant at ε < ε1 « 1. Characteristic scale ε1 is much larger than the width ε2 of the thermodynamical critical region, that is determined via the Ginzburg criterion, ε2 ≈ ε1d. We argue that in the intermediate region ε2 < ε < ε1 paraconductivity follows the same AL power law, albeit with another (yet unknown) numerical prefactor. At further decrease of the temperature, all kinds of fluctuational corrections become strong at ε < ε2; in particular, conductivity occurs to be strongly inhomogenuous in real space.

Perturbed Kitaev model: excitation spectrum and long-ranged spin correlations

22 September 2017 in 11:30

A.V. Lunkin, K.S. Tikhonov, M.V. Feigel’man

Dlya modeli Kitaeva na shestiugol’noi reshyotki s razlichnymi tipami vozmushchenii byl razrabotan metod podschyota korrelyatsionnoi funktsii spin-spin v infrakrasnom predele. Bylo pokazano, chto zadacha o podschyote dannoi funktsii mozhet byt’ svedena k zadache o nakhozhdenii korrelyatsionnoi funktsii kvadratichnykh operatorov, sostoyashchikh iz svobodnykh Maioranovskikh fermionov. Pri etom vklad vysshikh poryadkov teorii vozmushchenii dlya iskhodnoi zadachi mozhet byt’ uchtyon kak kvadratichnoe vozmushchenie dlya etikh fermionov. V kachestve prilozhenii rassmotreny sleduyushchie vozmushcheniya: magnitnoe pole, DM vzaimodeistvie cherez odnogo.

On Heavy Quarks in the Quark-Gluon Plasma and String Theory

15 September 2017 in 11:30

Oleg Andreev

I will discuss two issues related to heavy quarks in the strongly coupled quark gluon plasma from the string theory viewpoint. I begin with the expectation value of the Polyakov loop in the deconfined phase or, equivalently, the heavy quark free energy at finite temperature. Then, I continue with the relation between the drag force coefficient and the spatial string tension.

New Kaluza-Klein Instantons and Decay of AdS Vacua

8 September 2017 in 11:30

Lev Spodyneiko

We construct a generalization of Witten’s Kaluza-Klein instanton, where a higher-dimensional sphere (rather than a circle as in Witten’s instanton) collapses to zero size and the geometry terminates at a bubble of nothing, in a low energy effective theory of M theory. We use the solution to exhibit instability of non-supersymmetric AdS5 vacua in M Theory compactified on positive Kahler-Einstein spaces, providing a further evidence for the recent conjecture that any non-supersymmetric anti-de Sitter vacuum supported by fluxes must be unstable.

Uravnenie dlya odnomernykh voln na vode.

1 September 2017 in 11:30

A.I. Dyachenko

Dlya glubokoi vody polucheno odnomernoe uravnenie i gamil’tonian dlya voln, begushchikh v obe storony. Uravnenie polucheno s pomoshch’yu kanonicheskogo preobrazovaniya, kotoroe isklyuchaet vse nerezonansnye (trekh- i chetyrekhvolnovye) chleny v iskhodnom gamil’toniane. Polucheny ego prosteishie resheniya, odnim iz kotorykh yavlyaetsya nelineinaya stoyachaya volna.

Transport in a disordered ν=2/3 fractional quantum Hall junction

23 June 2017 in 11:30

Ivan Protopopov

Electric and thermal transport properties of a ν=2/3 fractional quantum Hall junction are analyzed. We investigate the evolution of the electric and thermal two-terminal conductances, G and G_Q, with system size L and temperature T. This is done both for the case of strong interaction between the 1 and 1/3 modes (when the low-temperature physics of the interacting segment of the device is controlled by the vicinity of the strong-disorder Kane-Fisher-Polchinski fixed point) and for relatively weak interaction, for which the disorder is irrelevant at T=0 in the renormalization-group sense. The transport properties in both cases are similar in several respects. In particular, G(L) is close to 4/3 (in units of e2/h) and G_Q to 2 (in units of πT/6ℏ) for small L, independently of the interaction strength. For large L the system is in an incoherent regime, with G given by 2/3 and GQ showing the Ohmic scaling, G_Q\sim 1/L, again for any interaction strength. The hallmark of the strong-disorder fixed point is the emergence of an intermediate range of L, in which the electric conductance shows strong mesoscopic fluctuations and the thermal conductance is G_Q=1. The analysis is extended also to a device with floating 1/3 mode, as studied in a recent experiment [A. Grivnin et al, Phys. Rev. Lett. 113, 266803 (2014)].

Hamiltonian Integration Method for Nonlinear Schrödinger Equation. Comparison with split-step method.

23 June 2017 in 11:30

A. Semenova and A.O. Korotkevich

V dannom korotkom soobshchenii predstavleny rezul’taty sravneniya dvukh chislennykh metodov: shiroko rasprostranyonnogo metoda split-step, osnovannogo na rasshcheplenii operatorov, i metoda Gamil’tonovskogo integrirovaniya, vpervye predlozhennogo v rabote D’yachenko i dr. 92-go goda. V rezul’tate sravneniya sokhraneniya kak trivial’nykh (deistvie i Gamil’tonian) tak i pervykh dvukh netrivial’nykh (poluchayushchikhsya iz integriruemosti sistemy) integralov dvizheniya pokazano, chto metod Gamil’tonovskogo integrirovaniya yavlyaetsya predpochtitel’nym, t.k. pri tom zhe urovne tochnosti pozvolyaet proizvodit’ vychisleniya s sushchestvenno bol’shim shagom po vremeni.

Magnitnye vikhri v ploskom nanoelemente i veshchestvennye differentsialy Abelya i Prima.

16 June 2017 in 11:30

A.B. Bogatyrev, Institut vychislitel’noi matematiki RAN (sovmestno s K.L. Metlovym, DonFTI)

Tonkaya struktura magnitnykh tekstur ferromagnetika opredelyaetsya mnogimi faktorami. V sluchae ploskogo magnetika submikronnykh razmerov dominiruyushchim yavlyaetsya geizenbergovskoe obmennoe vzaimodeistvie. Metastabil’nye sostoyaniya v modeli K.L. Metlova [Phys. Rev. Lett. 105, 107201 (2010)] – eto garmonicheskie otobrazheniya iz oblasti, zanimaemoi magnetikom, v sferu, s granichnymi usloviyami tipa neprotekaniya. D.Gross v 1978 godu predlozhil seriyu lokal’nykh reshenii s osobennostyami, modeliruyushchimi vikhri. Obshchee reshenie etogo vida s ukazannymi granusloviyami mozhno yavno opisat’ v terminakh t.n. veshchestvennykh differentsialov, abelevykh ili Prima s polozhitel’noi monodromiei. V ramkakh etoi modeli dlya mnogosvyaznogo magnetika byli predskazany topologicheskie effekty, nablyudaemye v eksperimente [Phys. Rev. B 95, 024403 (2017)].

Poiski polimorfnykh prevrashchenii v tverdoi faze i dinamika rasprostraneniya i otrazheniya sil’noi, lazerno-indutsirovannoi udarnoi volny v plenke tantala

9 June 2017 in 11:30

Nail’ Inogamov

V fizike vysokikh davlenii vazhnoe mesto zanimayut poiski kristallicheskikh modifikatsii metallov. V eksperimentakh idut dvumya putyami. Vo-pervykh, eto staticheskie izmereniya v almaznykh nakoval’nyakh. Vo-vtorykh, udarno-volnovye (UV) eksperimenty. Amplitudy davlenii v nakoval’nyakh limitirovany znacheniyami 2-4 Mbar, khotya v edinichnykh opytakh dokhodyat do znachenii 6-8 Mbar (Dubrovinskie). Udarnye volny mozhno sozdat’ s ochen’ vysokimi szhatiyami, zdes’ ogranichenie obuslovleno teplovym effektom, verkhnyaya granitsa svyazana s plavleniem kristalla (neskol’ko megabar). Poiski prevrashchenii v UV opytakh yavlyayutsya traditsionnym napravleniem issledovanii. Pri etom ispol’zuyut tekhniku Velocity interferometer system for any reflector (VISAR); OIVT RAN, Kanel’, Fortov, Razorenov, Utkin i dr. VISAR sledit za traektoriei kontakta plenki s vakuumom, to, chto proiskhodit vnutri otrazhaetsya na etoi traektorii, no ne vidno neposredstvenno. I, konechno, VISAR dalek ot razresheniya protsessov na atomnykh masshtabakh i pri ochen’ vysokikh tempakh deformatsii. V eksperimente, o kotorom idet rech’, opticheskii subnanosekundnyi lazernyi impul’s generiruet UV v mikronnoi plenke tantala. Slezhenie za rasprostraneniem i otrazheniem UV ot tyl’noi (t.e. obratnoi k obluchennoi) granitsy plenki osushchestvlyaetsya s pomoshch’yu serii femtosekundnykh zhestokikh (neskol’ko keV, dlina volny v Angstremakh) rentgenovskikh impul’sov ot lazera na svobodnykh elektronakh (RIKEN/HARIMA X-ray free electron laser XFEL), "mgnovenno" pronizyvayushchikh plenku i difragiruyushchikh na sil’no deformirovannoi reshetke. Takim obrazom, vpervye, my vidim proiskhodyashchee vnutri kristalla za frontom UV na atomnom prostranstvenno-vremennom masshtabe. Poluchennye dannye slozhny, poskol’ku UV yavlyaetsya nestatsionarnoi. Nami ispol’zovany chislennye kody, kotorye pozvolili ponyat’ i opisat’ protekayushchie yavleniya. Lyuboi eksperiment po ukazannoi metodike dolzhen soprovozhdat’sya gidrodinamicheskim i krupnomasshtabnym atomisticheskim chislennym modelirovaniem, chtoby otdelit’ dinamicheskie effekty ot polimorfnogo prevrashcheniya kristall-kristall. [Science Advances 02 Jun 2017: Vol. 3, no. 6, e1602705, DOI: 10.1126/sciadv.1602705]

Issledovanie fazovykh perekhodov pervogo roda s pomoshch’yu algoritma otzhiga populyatsii

2 June 2017 in 11:30

L.N. Shchur, L. Barash, M. Weigel, W. Janke

Algoritm otzhiga populyatsii (population annealing algorithm) osnovan na kombinatsii dvukh metodov Monte-Karlo - relaksatsii pri zadannoi temperature i obnovlenii populyatsii pri izmenenii temperatury. Ozhidaetsya, chto etot metod osobo effektiven v sluchae sistem so slozhnym energeticheskim spektrom. Po-krainei mere, on daet pravil’nyi rezul’tat dlya osnovnogo sostoyaniya frustrirovannogo antiferromagnetika, chto do sikh por ne udavalos’ poluchit’ s pomoshch’yu drugikh metodov. Ya rasskazhu o tom, chto novogo mozhno ozhidat’ ot etogo metoda v sluchae fazovogo perekhoda pervogo roda. Etot metod, v chastnosti, daet vozmozhnost’ pryamogo vychisleniya svobodnoi energii, chto, v sluchae fazovogo perekhoda pervogo roda, pozvolyaet otsenit’ s khoroshei tochnost’yu temperaturu perekhoda.

Neeksponentsial’noe zatukhanie vrashcheniya spina v radiochastotnom rezonanse v nakopitele za schet sinkhrotronnykh kolebanii impul’sa

26 May 2017 in 11:30

N.N. Nikolaev

Vertikal’naya polyarizatsiya puchka v staticheskom nakopitele sokhranyaetsya. Radiochastotnye polya s chastotoi, ravnoi chastote pretsessii spina, indutsiruyut ostsillyatsii spina vverkh-vniz. Uslovie rezonansa narushaetsya sinkhrotronnymi kolebaniyami chastits v nakoplennom puchke. Pokazano, chto vyzvannoe etim zatukhanie amplitudy rezonansnykh kolebanii nosit ne eksponentsial’nyi, a stepennoi kharakter.

Novyi podkhod k vychisleniyu nizkoenergeticheskogo effektivnogo Lagranzhina, kotoryi voznikaet v Teorii Superstrun posle kompaktifikatsii 6-ti iz 10-ti izmerenii na mnogoobraziya Kalabi-Yau

19 May 2017 in 11:30

K. Aleshkin i A. Belavin (dokladchik)

Teoriya strun - edinstvennaya pridumannaya teoretikami ideya ob’edineniya Gravitatsii i Standartnoi Modeli. A Supersimmetriya (narushennaya) Prostranstva-Vremeni v effektivnoi teorii polya, kotoraya posle kompaktifikatsii 6-ti iz 10-ti izmerenii na mnogoobraziya Kalabi-Yau, yavlyaetsya estestvennym sposobom reshit’ t. n. problemu ierarkhii, to est’ otvetit’ na vopros: pochemu massa bozona Khiggsa na stol’ko poryadkov men’she massy Planka? Kompaktifikatsiya na mnogoobraziya Kalabi-Yau malogo razmera neobkhodima dlya obespecheniya Supersimmetrii v Prostranstve-Vremeni. Takie kharakteristiki Teorii, kak chislo pokolenii kvarkov-leptonov, opredelyayutsya topologiei komaktifitsiruyushchikh mnogoobrazii Kalabi-Yau. A dinamika supermul’tipletov zadaetsya geometriei prostranstva parametrov, ot kotorykh zavisyat eti mnogoobraziya. My predlagaem novyi sposob vychisleniya etoi t. n. Spetsial’noi Kellerovoi Geometrii.

Domains, switching and negative capacitance in nano-scale ferroelectrics

19 May 2017 in 11:30

Igor Lukyanchuk

Formation of unusual textures of polarization is imminent for nano-scale ferroelectric samples, films, rods, and granules, where the depolarization surface effects play the crucial role. We consider the unconventional topological polarization textures in several nano-scale systems, in which they were either already directly observed or can be yet discovered. Polarization domains that alternate the surface charge distribution, first proposed by Landau (1935) in contents of ferromagnetism can be formed in ferroelectric thin films as an effective mechanism to confine the depolarization field to the near-surface layer and diminish the depolarization energy. Very recently we have demonstrated that the few-nanometer thick ferroelectric/paraelectric superlattices with periodic domain structures exhibit the striking feature. The effective capacitance of ferroelectric layers is negative. This effect is explained by the opposite orientation of the depolarizing field with respect to the field-induced averaged polarization. Moreover, in sub-THz region the real part of the dielectric constant becomes positive, passing through zero at frequency ~0.3-3THz, inducing the resonance effect, suitable for the design of the ultra-small low-energy THz chips. Multi-vortex and skyrmion states are formed inside ferroelectric cylindrical nano-dots and nanorods to reduce the depolarization energy. We study the stability of such states and calculate the phase diagram of the system. We demonstrate that the topological class of the most stable topological excitations can be driven by the geometrical and electrical parameters of the system, external field, and temperature. We target the multi-domain and topological excitations in FE nanodots as a platform for multivalued logic units, for neuromorphic computing.

Anizotropiya elektronnykh transportnykh i sverkhprovodyashchikh svoistv v FeSe

28 April 2017 in 11:30

P.G. Grigor’ev

Naideno i kolichestvenno opisano obshchee svoistvo: esli neodnorodnaya sverkhprovodimost’ v anizotropnom provodnike poyavlyaetsya v vide izolirovannykh sverkhprovodyashchikh ostrovkov, ona umen’shaet elektricheskoe soprotivlenie anizotropno s maksimal’nym effektom vdol’ osi s naimen’shei provodimost’yu. Eto svoistvo daet prostoi i ochen’ obshchii instrument dlya izucheniya neodnorodnoi (ostrovkovoi) sverkhprovodimosti v razlichnykh anizotropnykh soedineniyakh i pozvolyaet otsenit’ velichinu i temperaturnuyu zavisimost’ ob’emnoi doli sverkhprovodyashchei fazy. Yavlenie nablyudaetsya v razlichnykh vysokotemperaturnykh sverkhprovodnikakh i v organicheskikh metallakh.

C pomoshch’yu opisannogo svoistva i izmerenii elektronnoi provodimosti i diamagnetizma vpervye pokazano poyavlenie neodnorodnoi sverkhprovodimosti v ob’emnom soedineniya FeSe pri atmosfernom davlenii i pri temperature v 5 raz vyshe, chem izvestnaya ranee temperatura sverkhprovodyashchego perekhoda Tc=8K, sootvetstvuyushchaya nulevomu soprotivleniyu. Eto otkrytie pomogaet ponyat’ mnogochislennye neobychnye sverkhprovodyashchie svoistva FeSe, takie kak pyatikratnoe povyshenie Tc pri uvelichenii davleniya do neskol’kikh kilobar. Obsuzhdaetsya vozmozhnost’ primeneniya etogo svoistva dlya obnaruzheniya prostranstvenno neodnorodnoi sverkhprovodimosti v drugikh anizotropnykh soedineniyakh, takikh kak kupraty i organicheskie metally.

Algebraicheskii podkhod k form faktoram modeli kompleksnogo sinh-Gordon

21 April 2017 in 11:30

Yaroslav Pugai

Predlozheny tochnye vyrazheniya dlya form faktorov eksponentsial’nykh polei i polei-potomkov v integriruemoi massivnoi modeli kvantovoi teorii polya, kotoraya yavlyaetsya dual’noi k modeli kompleksnogo sinh-Gordon. Algebraicheskii podkhod osnovan na razvitii metodov, primenennykh ranee dlya modelei sinh-Gordon i Z(n) modelei.

Some new results on Belief Propagation, Loop Calculus, Sampling and Gauge Transformations

14 April 2017 in 11:30

M. Chertkov (Skoltech + on leave from LANL)

In this talk I plan to review recent progress made in constructing practical algorithms for computing partition function of a general loopy graphical model. After some introductory material, setting up notations and explaining the Loop Calculus approach (Chertkov, Chernyak 2006), I will turn to explaining new results on 1) constructing Markov Chain which allows to sample from the Loop Series built around a Belief Propagation solution (based on "MCMC assisted by Belief Propagation",; 2) exploring gauge freedom beyond Belief Propagation (based on "Gauge Optimization via ADMM for Approximate Inference",

Wave breaking and soliton turbulence of water waves

24 March 2017 in 11:30

A. Dyachenko and D. Kachulin

We study numerically soliton turbulence at the surface of deep water. One of the main problem here is wave breaking that happens from time to time. We propose a model to take it into account.

Magnetic disorder in superconductors: Enhancement by mesoscopic fluctuations

17 March 2017 in 11:30

I.S. Burmistrov, M.A. Skvortsov

We study the density of states (DOS) and the transition temperature Tc in a dirty superconducting film with rare classical magnetic impurities of an arbitrary strength described by the Poissonian statistics. We take into account that the potential disorder is a source for mesoscopic fluctuations of the local DOS, and, consequently, for the effective strength of magnetic impurities. We find that these mesoscopic fluctuations result in a non-zero DOS for all energies in the region of the phase diagram where without this effect the DOS is zero within the standard mean-field theory. This mechanism can be more efficient in filling the mean-field superconducting gap than rare fluctuations of the potential disorder (instantons). Depending on the magnetic impurity strength, the suppression of Tc by spin-flip scattering can be faster or slower than in the standard mean-field theory.

Perekhod Frederiksa i odnomernye tekstury v dvukhosnykh nematikakh

10 March 2017 in 11:30

V.N. Blinov, V.L. Golo, E.I. Kats, A.A. Sevenyuk, D.O. Sinitsyn

My (v osnovnom chislenno) izuchili tekstury (to est’ neodnorodnye sostoyaniya orientatsionnogo parametra poryadka) v dvukhosnykh nematicheskikh ili kholestericheskikh zhidkikh kristallakh. Teoriya takikh tekstur tesno svyazana s matematichskoi teoriei dvukhosnykh volchkov (giroskopov). Takim zhe obrazom izucheny teksturnye preobrazovaniya vo vneshnikh elektricheskikh ili magnitnykh polyakh.

Kraevye effekty v malom fokal’nom pyatne pri vozdeistvii ul’trakorotkogo lazernogo impul’sa na tonkuyu plenku

3 March 2017 in 11:30

V.V. Shepelev, N.A. Inogamov, V.V. Zhakhovskii

Odnim iz vazhnykh napravlenii sredi lazernykh primenenii yavlyaetsya sozdanie uedinennykh nanostruktur posredstvom ostro sfokusirovannogo vozdeistviya. V rabote rassmatrivaetsya dvumernaya teplovaya zadacha, v kotoroi chislenno uchityvayutsya ne tol’ko potoki tepla po normali k poverkhnosti plenki (eto byla by odnomernaya zadacha), no i bokovoe rasprostranenie pogloshchennoi lazernoi energii po plenke pri takom vozdeistvii. Rastekanie v storony, vo-pervykh, skazyvaetsya na situatsii vblizi kraev kupola iz otorvavshegosya ot podlozhki uchastka plenki. Vo-vtorykh, temp otvoda tepla iz goryachego rasplavlennogo pyatna na dalekuyu kholodnuyu periferiyu plenki opredelyaet evolyutsiyu na stadii rekristallizatsii. Krome togo, privodyatsya rezul’taty molekulyarno-dinamicheskogo modelirovaniya, posvyashchennye analizu slozhnykh dinamicheskikh i teplovykh yavlenii vozle kraya kupola. Polozhenie kraya svyazano s tekushchim mestonakhozhdeniem zony plavleniya.

Ferromagnitnye zhidkie kristally.

17 February 2017 in 11:30

E.I. Kats

Budet dan kratkii obzor istorii i sovremennogo sostoyaniya nauki o magnitnykh zhidkikh kristallakh.

Ot idei do Messbauerovskogo istochnika na ESRF

17 February 2017 in 11:30

V.A. Belyakov

Privoditsya kratkii istoricheskii obzor teoreticheskikh i eksperimental’nykh rabot (v osnovnom otechestvennykh), odnim iz rezul’tatov kotorogo stalo sozdanie unikal’nogo istochnika messbauerovskogo izlucheniya na Evropeiskom istochnike Sinkhrotronnogo Izlucheniya v Grenoble (ESRF). Obsuzhdayutsya unikal’nye fizicheskie rezul’taty, poluchennye s primeneniem etogo pribora i perspektivy dal’neishego rasshireniya etikh rabot v oblasti fundamental’nykh i prikladnykh issledovanii.

Entanglement entropy and particle number cumulants of disordered fermions

10 February 2017 in 11:30

I.S Burmistrov

We study the entanglement entropy and particle number cumulants for a system of disordered noninteracting fermions in d dimensions. We show, both analytically and numerically, that for a weak disorder the entanglement entropy and the second cumulant (particle number variance) are proportional to each other with a universal coefficient. The corresponding expressions are analogous to those in the clean case but with a logarithmic factor regularized by the mean free path rather than by the system size. We also determine the scaling of higher cumulants by analytical (weak disorder) and numerical means. Finally, we predict that the particle number variance and the entanglement entropy are nonanalytic functions of disorder at the Anderson transition.

Vzaimovliyanie kulonovskoi blokady, ferroelektrichestva i elektronnogo transporta v mezoskopicheskikh nanostrukturakh

23 December 2016 in 11:30

N.M. Shchelkachev

We investigate the interplay of ferroelectricity and quantum electron transport at the nanoscale in the regime of Coulomb blockade. Ferroelectric polarization in this case is no longer the external parameter but should be self-consistently calculated along with electron hopping probabilities leading to new physical transport phenomena.

Itogi goda: obzor rabot sektora plazmy i lazerov i perspektivy na 2017 g.

16 December 2016 in 11:30

Anisimov S.I., Inogamov N.A., Petrov Yu.P., Khokhlov V.A.

Fizika vzaimodeistviya lazernogo izlucheniya s veshchestvom imeet mnozhestvo prilozhenii i, konechno, kak lyubaya bystro razvivayushchayasya vetv’ nauki, ryad nereshennykh problem. Issleduyutsya voprosy pogloshcheniya sveta, teplovye i mekhanicheskie protsessy, initsiirovannye lazernym impul’som. Osnovnoe vnimanie v soobshchenii udelyaetsya sovremennym vozmozhnostyam manipulyatsii elektromagnitnym polem na nanomasshtabakh i vo vremeni i vozdeistviyu na slozhnye ob’ekty: plenka na podlozhke, mnogosloinye pokrytiya (rentgenovskie zerkala, odnomernye fotonnye kristally) i malye ob’ekty: nanochastitsa na podlozhke ili mikrokupol na plenke

Dinamika pryamykh vikhrevykh nitei v boze-kondensate s gaussovym profilem plotnosti

9 December 2016 in 11:30

V.P. Ruban

Rassmotrena v gidrodinamicheskom ``bezelastichnom'' priblizhenii dinamika vzaimodeistvuyushchikh kvantovannykh vikhrevykh nitei vo vrashchayushchemsya boze-kondensate, kotoryi nakhoditsya v rezhime Tomasa-Fermi pri nule temperatury i podchinyaetsya uravneniyu Grossa-Pitaevskogo. Pri nalichii plavno neodnorodnogo massiva nitei (vikhrevoi reshetki) polucheno nekanonicheskoe gamil’tonovo uravnenie dvizheniya dlya makroskopicheski usrednennoi zavikhrennosti s uchetom prostranstvennoi neodnorodnosti ravnovesnoi plotnosti kondensata, opredelyaemoi potentsialom lovushki. Minimum sootvetstvuyushchego gamil’toniana opisyvaet staticheskuyu konfiguratsiyu deformirovannoi vikhrevoi reshetki na zadannom fone plotnosti. Uslovie minimuma svoditsya k vektornomu nelineinomu uravneniyu v chastnykh proizvodnykh vtorogo poryadka, dlya kotorogo naideny nekotorye tochnye i priblizhennye resheniya. Pokazano, chto esli plotnost’ kondensata imeet anizotropnyi gaussov profil’, to uravnenie dvizheniya dlya usrednennoi zavikhrennosti dopuskaet resheniya v vide netrivial’no zavisyashchego ot vremeni, no odnorodnogo po prostranstvu vektora. Polucheno takzhe integral’noe predstavlenie dlya matrichnoi funktsii Grina, kotoraya opredelyaet nelokal’nyi gamil’tonian sistemy neskol’kikh kvantovannykh vikhrevykh nitei proizvol’noi formy v boze-kondensate s gaussovoi plotnost’yu. V chastnosti, esli vse niti pryamye i orientirovany vdol’ odnoi iz glavnykh osei ellipsoida, to poluchaetsya konechnomernaya reduktsiya, sposobnaya opisat’ dinamiku sistemy tochechnykh vikhrei na neodnorodnom fone. Predlozheno prostoe priblizhennoe vyrazhenie dlya dvumernoi funktsii Grina pri dostatochno proizvol’nom profile plotnosti i provedeno ego chislennoe sravnenie s tochnym rezul’tatom v gaussovom sluchae. Vyvedeny sootvetstvuyushchie priblizhennye uravneniya dvizheniya, opisyvayushchie dlinnovolnovuyu dinamiku vzaimodeistvuyushchikh vikhrevykh nitei v kondensatakh s plotnost’yu, zavisyashchei tol’ko ot poperechnykh koordinat.

Skyrmion Dynamics in Ferromagnets and Antiferromagnets

25 November 2016 in 11:30

Oleg Tretiakov (Tohoku University, Japan)

Manipulating small spin textures that can serve as bits of information by electric and spin currents is one of the main challenges in the field of spintronics. Ferromagnetic skyrmions recently attracted a lot of attention because they are small in size and are better than domain walls at avoiding pinning sites while moved by electric current. Nevertheless, ferromagnetic skyrmions also have certain disadvantages, such as the presence of stray fields and transverse dynamics, making them harder to employ in spintronic devices. To avoid these unwanted effects, we propose a novel topological object: the antiferromagnetic (AFM) skyrmion and explore its properties using analytical theory based on generalized Thiele equation and micromagnetic simulations. This topological texture has no stray fields and we show that its dynamics are faster compared to its ferromagnetic analogue. We obtain the range of stability and the dependence of AFM skyrmion radius on the strength of Dzyaloshinskii-Moriya interaction coming from relativistic spin-orbit effects. Moreover, we study the temperature effects on the stability and mobility of AFM skyrmions. We find that the thermal properties, e.g. such as the antiferromagnetic skyrmion radius and diffusion constant, are rather different from those for ferromagnetic skyrmions. More importantly, we show that due to unusual topology the AFM skyrmions do not have a velocity component transverse to the current (no topological Hall effect), and thus may be interesting candidates for spintronic memory and logic applications.

On Self-Dual Yang-Mills Theory

18 November 2016 in 11:30

Igor’ Polyubin

We discuss renormalization of the theory and calculate corresponding beta-functions. Also we compute some exact two and three point correlatoion functions and four point (++++) amplitude and check their conformal invariance.

Two-instanton approximation to the Coulomb blockade problem

14 October 2016 in 11:30

Burmistrov I.S.

We develop the two-instanton approximation to the current-voltage characteristic of a single electron transistor within the Ambegaokar-Eckern-Sch\"on model. We determine the temperature and gate voltage dependence of the Coulomb blockade oscillations of the conductance and the effective charge. We find that a small (in comparison with the charging energy) bias voltage leads to significant suppression of the Coulomb blockade oscillations and to appearance of the bias-dependent phase shift.

Weakly Nonlinear Nonlocal Equation for Envelope of Water Waves

14 October 2016 in 11:30

A.I. Dyachenko

For deep water waves the equation for the envelope is derived. The equation is nonlocal. The assumption of a narrowness of spectral band around a characteristic wave is not is necessary. Thus, this equation is suitable for description of extreme waves (freak waves).

Analogous black-holes in Bose-Einstein condensates: how to create them and how to detect the associated (sonic) Hawking radiation ?

7 October 2016 in 11:30

Nicolas Pavloff, LPTMS (Orsay)

A "dumb hole" is the sonic equivalent of a black hole: it is a stationary flow pattern in which the downstream flow is supersonic whereas the upstream one is subsonic (as in a de Laval nozzle). In 1981, Unruh suggested that dumb holes should emit a sonic radiation analogous to the celebrated Hawking radiation of black holes.
I shall first present realistic realizations of a sonic event horizon in a 1D Bose-Einstein condensate. In a second stage I will discuss possible (quantum and classical) signatures of the sonic analogous of Hawking radiation in these systems. I will also address the recent experimental results of Steinhauer [Nature Physics (2016)]

Mesoscopic fluctuations of the single-particle Green's function at Anderson transitions with Coulomb interaction

30 September 2016 in 11:30

Burmistrov I.S.

Using the two-loop analysis and the background field method we demonstrate that the local pure scaling operators without derivatives in the Finkel'stein nonlinear sigma model can be constructed by straightforward generalization of the corresponding operators for the noninteracting case. These pure scaling operators demonstrate multifractal behavior and describe mesoscopic fluctuations of the single-particle Green's function. We determine anomalous dimensions of all such pure scaling operators in the interacting theory within the two-loop approximation.

23 September 2016 in 11:30

Gordei Lesovik

V doklade budet rasskazano o rezul’tatakh, poluchennykh v nedavnikh rabotakh: 1) N-teorema v kvantovoi fizike [G.B. Lesovik, A.V. Lebedev, I.A. Sadovskyy, M.V. Suslov, V.M. Vinokur, H-theorem in quantum physics, Sci. Rep. (Nature Publishing Group) 6, 32815 (2016)]. 2)Trading coherence and entropy by a quantum Maxwell demon [A. V. Lebedev, D. Oehri, G. B. Lesovik, G. Blatter (PRA 2016)]. 3) Phase Estimation Algorithms for Quantum Metrology with a Single Qubit [S. Danilin, A. Vepsalainen, A. V. Lebedev, G. B. Lesovik, G. Blatter, G. S. Paraoanu, in preparation)].

Physics at the Edge: A New Paradigm for Shot Noise

16 September 2016 in 11:30

Yuval Gefen (Weizmann Institute of Science)

Questions on the nature of edge reconstruction and ‘where does the current flow’ in the quantum Hall effect (QHE) have been debated for years. Moreover, the recent observation of proliferation of ‘upstream’ neutral modes in the fractional QHE raised doubts about the present models of edge channels. I will focus on the hole-conjugate state \nu=2/3 , and present a new picture of edge reconstruction. For example, while the hitherto accepted model for \nu=2/3 consists of a single downstream charge channel with conductance 2/3 and an upstream neutral mode, it has been recently predicted theoretically and found experimentally that the current is carried by two separate downstream edge channels, each with conductance 1/3 accompanied by upstream neutral mode(s). We find that if the two downstream channels are not equilibrated, inter-mode equilibration (via particle exchange) is accompanied by an excitation of upstream neutral modes. In turn, the counter-propagating neutral modes, moving in close proximity to the charge modes, fragment into propagating charges, inducing thus downstream current fluctuations with zero net current – a novel mechanism for non-equilibrium noise. The latter is shot noise with quantized Fano factors, which does not involve beam partitioning.

Dynamic correlations in 1D superfluids: the particle-wave duality

9 September 2016 in 11:30

Dimitri M. Gangardt (University of Birmingham)

While phonons are routinely used to describe low-energy properties of quantum superfluids, repulsive bosons in one dimension are special: their low energy excitations allow for an alternative decription in terms of fermionic quasiparticles. In my talk I will present the quasiclassical theory of these excitations which allows calculation of the dynamical structure factor in a generic 1D Bose liquid. In this theory the main role is played by singular kink-like configurations of the bosonic field. I will demonstrate that it is the kinetics of these quasiparticles rather than hydrodynamics which provides an effective description of dynamics of 1D interacting bosons.

Flat Coordinates on Frobenius Manifolds in the case of the irrelevant deformations

2 September 2016 in 11:30

L. Spodyneiko

We use the suggested recently conjecture about the integral representation for the flat coordinates on Frobenius manifolds connected with isolated singularities to compute the flat coordinates for the deformed Gepner chiral ring SU(3)4 .
We verify this conjecture by comparing expressions for the flat coordinates obtained from the conjecture with one found by direct computation. The considered case of is of particular interest since together with the relevant and marginal deformations it has one irrelevant deformation.

Chetyryokhtochechnye korrelyatsionnye chisla v minimal’noi liuvillevskoi gravitatsii i diskretnye chleny Liuvillevskogo OR

2 September 2016 in 11:30

K. Aleshkin

V Minimal’noi Liuvillevskoi Gravitatsii raschet korrelyatsionnykh chisel ili tak nazyvaemykh amplitud Venetsiano svyazan s integrirovaniem po prostranstvam modulei kompleksnykh krivykh. Dva nezavisimykh podkhoda k vychisleniyu, osnovannye libo na vysshikh uravneniyakh dvizheniya konformnoi teorii Liuvillya, libo na ispol’zovanii strunnogo uravneniya Duglasa, dayut rezul’taty, kotorye ne vsegda soglasovany mezhdu soboi. V doklade budet rasskazano o priblizhyonnom chislennom vychislenii korrelyatsionnykh chisel, o problemakh sopostavleniya rezul’tatov nezavisimykh podkhodov i o vozmozhnosti ikh razresheniya. Budet pokazano, chto znachitel’nuyu rol’ v reshenii problemy igraet uchet tak nazyvaemykh diskretnykh chlenov v operatornom razlozhenii teorii Liuvillya.

Closed equations for the jump along branch cut of Stokes wave

17 June 2016 in 11:30

Pavel Lushnikov

2D hydrodynamics of ideal fluid with free surface can be addressed through jump at the branch cuts in the complex plane. The particular example is the Stokes wave which is the nonlinear gravity wave propagating with the constant velocity. The near-limiting Stokes wave is considered which poses a challenge for simulations based on Fourier transform because of the approach of the branch point to the real line in the complex plane. Instead the closed equations on the branch cut are considered. However, numerical quadratures for such equations have extreme ill-conditioning making them impossible to use. Instead the analytical information about jump of the branch cut is used to construct the analytic quadrature significantly suppressing ill-conditioning. It suggest the efficient way to address 2D turbulence of highly nonlinear water waves through the dynamics of branch cuts.

Atomnye protsessy na poverkhnosti kremniya pri vysokikh temperaturakh

10 June 2016 in 11:30

Sergei Sergeevich Kosolobov (Skoltekh, IFP SO RAN)

Predstavleny rezul’taty issledovanii atomnykh protsessov, protekayushchikh na poverkhnosti monokristallicheskogo kremniya, v usloviyakh sublimatsii, epitaksial’nogo rosta, osazhdeniya zolota i termicheskogo travleniya kislorodom pri vysokikh (>900 C) temperaturakh. Issledovaniya provodilis’ unikal’nym metodom in situ sverkhvysokovakuumnoi otrazhatel’noi elektronnoi mikroskopii, pozvolyayushchim vizualizirovat’ atomnye stupeni, dvumernye ostrovki, sverkhstrukturnye domeny i drugie defekty poverkhnosti v shirokom diapazone temperatur i s vysokim vremennym razresheniem. Proveden detal’nyi analiz kinetiki atomnykh stupenei na vitsinal’noi i litograficheski strukturirovannoi poverkhnostyakh kremniya (111) v protsesse sublimatsii. Issledovany protsessy zarozhdeniya i razrastaniya dvumernykh ostrovkov kremniya pri vysokotemperaturnom gomoepitaksial’nom roste. Izucheny mekhanizmy formirovaniya dvumernykh otritsatel’nykh (vakansionnykh) ostrovkov pri termicheskom travlenii poverkhnosti kremniya molekulyarnym kislorodom. Predstavleny rezul’taty issledovaniya nestabil’nosti atomnykh stupenei na poverkhnosti kremniya pri submonosloinom osazhdenii zolota. Na osnovanii provedennykh issledovanii opredelen ryad kolichestvennykh parametrov (energii aktivatsii diffuzii adatomov i vakansii, vzaimodeistviya so stupenyami, razmer kriticheskogo zarodysha i dr.), kharakterizuyushchie atomnye protsessy massoperenosa na poverkhnosti kremniya pri vysokikh temperaturakh.

Simulation of gas transportation networks

3 June 2016 in 11:30

S.A. Dyachenko, A. Zlotnik, A.O. Korotkevich, M. Chertkov

Predstavlen novyi chislennyi metod modelirovaniya uravenii opisyvayushchikh techenie gaza v gazotransportnykh setyakh. Metod sokhranyaet massu gaza po postroeniyu. Rassmotreny kak modelirovanie uravnenii na grafe seti, tak i priblizhenie raspredelyonnykh istochnikov i kompressorov, primenimoe dlya dlinnykh truboprovodov po tipu truby Kh’yuston-Boston tyanushcheisya vdol’ vostochnogo poberezh’ya SShA. Rassmotreno vliyanie fluktuatsii potrebleniya v trube, privodyashchee k rostu fluktuatsii davleniya. Proizvedeno sravnenie predlozhennogo metoda s ranee primenyavshimisya.

Elektrony na obez’yan’em sedle: chetvernaya tochka Lifshitsa

3 June 2016 in 11:30

A. Shtyk, G. Goldstein, K. Shamon

My rassmatrivaem 2D vzaimodeistvuyushchie elektrony s dispersiei tipa "obez’yan’e sedlo" (OS), $\propto p_x^3-3p_xp_y^2$. Podobnaya dispersiya estestvenno voznikaet pri sliyanii trekh obychnykh sedel (osobennostei van Khova) v elementarnoi katastrofe tipa ellipticheskoi ombiliki. My pokazyvaem, chto takaya dispersiya voznikaet v dvukhsloinom grafene v poperechnom elektricheskom pole, prichem s tochki zreniya topologii poverkhnosti Fermi podobnaya singulyarnost’ yavlyaetsya chetvernoi tochkoi Lifshitsa. Tochka Lifshitsa etogo tipa obladaet kharakternym povedeniem urovnei Landau $E_m\propto (Bm)^{3/2}$ i svyazannykh ostsillyatsii v termodinamicheskikh i transportnykh svoistvakh, takikh kak ostsillyatsii de-Gaaza-van-Al’fena i Shubnikova-de-Gaaza, chei period utraivaetsya pri peresechenii singulyarnosti. My demonstriruem, chto dlya izolirovannogo OS teoriya, opisyvayushchaya nevzaimodeistvuyushchie elektrony, neustoichiva po otnosheniyu k renormgruppovomu potoku, i v sisteme libo voznikaet sverkhprovodyashchaya neustoichivost’, libo ne-Fermi-zhidkostnoe povedenie. V dvukhsloinom grafene, v kotorom imeetsya dva OS okolo $K$ i $K^\prime$ tochek, voznikaet konkurentsiya neustoichivostei, a imenno ferromagnetizma, voln spinovoi i zaryadovoi plotnostei, i nematichnosti.

Konformnaya KEDd, F-teorema i ε-razlozhenie

27 May 2016 in 11:30

Grisha Tarnopol’skii

My vychislyaem svobodnuyu energiyu F dlya U (1) kalibrovochnykh teorii na d mernoi sfere radiusa R. Dlya teoriya so svobodnym deistviem Maksvella my nakhodim tochnyi rezul’tat kak funktsiyu ot d; Kogda U(1) kalibrovochnaya teoriya polya vzaimodeistvuet s bol’shim chislom Nf bezmassovykh 4-komponentnykh fermionov, v nei nablyudaetsya konformnaya faza, kotoraya pri d < 4 opisyvaet povedenie modeli na bol’shikh masshtabakh. Konformnaya faza mozhet byt’ izuchena s ispol’zovaniem 1/Nf razlozheniya. My vychislyaem svobodnuyu energiyu kak funktsiyu ot d, prenebregaya chlenami poryadka 1/Nf i vyshe. Dlya konechnogo Nf , my vychislyaem 4−ε razlozhenie dlya svobodnoi energii konformnoi KEDd na sfere. Dlya Nf men’she chem kriticheskoe znachenie Ncrit, predpolagaetsya, chto SU(2Nf) simmetrichnaya konformnaya faza QED3 stanovitsya nestabil’noi. Ispol’zuya F -teoremu i sveryaya svobodnuyu energiyu v konformnoi faze i narushennoi my pokazyvaem, chto Ncrit ≤ 4.

Kvazishtekkelevy gamil’toniany, kanonicheskie preobrazovaniya Beklunda i ikh prilozheniya (po materialam dlya doktorskoi dissertatsii)

27 May 2016 in 11:30

Marikhin V.G.

Pokazano, chto lyubaya para kommutiruyushchikh gamil’tonianov mozhet byt’ privedena k kanonicheskoi forme pary kvazishtekkelevykh gamil’tonianov kak v klassicheskom sluchae, tak i v kvantovom. Dlya etikh sistem poluchena funktsiya Gamil’tona - Yakobi. Poluchena algebraicheskaya krivaya, sootvetstvuyushchaya kvazishtekkelevoi gamil’tonovskoi dinamike. Obsuzhdaetsya "chastichnoe razdelenie peremennykh" v etom sluchae. V klassicheskom sluchae provedena klassifikatsiya etikh sistem. V kvantovom sluchae podrobno issledovan sluchai, sootvetstvuyushchii uravneniyu Shredingera. Provedena klassifikatsiya etogo sluchaya. Postroeno dva primera dvumernogo uravneniya Shredingera s magnitnym polem, okazalos’, chto eti primery otnosyatsya k sluchayu "pochti tochno reshaemykh sistem". Eti uravneniya prointegrirovany v terminakh funktsii Goina. Predlozhen metod postroeniya kanonicheskikh preobrazovanii Beklunda (PB), sostoyashchii v trebovanii invariantnosti variatsii deistviya otnositel’no etikh preobrazovanii. Privedeny primery takikh preobrazovanii dlya "divergentnykh" sistem, modeli Landau-Lifshitsa i pr. Otdel’no rassmatrivaetsya sluchai novykh PB dlya uravneniya Tsitseiki.

Vysoko-dobrotnyi plazmonnyi rezonans v ferromagnitnykh nanochastitsakh

20 May 2016 in 11:30

Khari Bkhatta, Ali Aliev, Vladimir P. Drachev(University of North Texas, Skoltekh)

Metallicheskie chastitsy malykh razmerov podderzhivayut vozbuzhdenie lokalizovannykh plazmonov. Voznikayushchie pri etom vysokie lokal’nye polya yavlyayutsya osnovnoi prichinoi usileniya opticheskikh otklikov, lineinykh i osobenno nelineinykh. Takie effekty kak gigantskoe kombinatsionnoe rasseyanie, usilenie fotolyuminestsentsii, usilenie radiatsionnoi relaksatsii vozbuzhdeniya, zavisimost’ ot geometrii metallicheskikh nanostruktur nashli primenenie v sensorakh, optoelektronike i metamaterialakh. Magnitnye nanochastitsy nikogda ne rassmatrivalis’ v kachestve skol’ko nibud’ priemlemykh kandidatov dlya plazmonnykh primenenii iz-za nizkoi provodimosti. Opticheskie izmereniya v UF/Vidimom/IK diapazone dlya tonkikh plenok i nanochastits podtverzhdali eto mnenie. Rezul’taty nashikh eksperimentov pokazali neozhidanno vysoko-dobrotnyi plazmonnyi rezonans v nanochastitsakh kobal’ta. Dlina volny etogo rezonansa nakhoditsya v ul’trafioletovoi chasti spektra, 275 nm. Plazmonnyi rezonans khoroshego kachestva v UF diapazone, gde mnogie biomolekuly imeyut elektronnye rezonansy, delaet nanochastitsy So privlekatel’nym materialom dlya biosensorov. V doklade budut obsuzhdat’sya rezul’taty spektral’nykh, strukturnykh i magnitnykh izmerenii nanochastits So sintezirovannykh nami v rastvore geksana. Nashi vyvody osnovany na predstavlenii ob odnodomennykh chastitsakh s polyarizatsiei spinov, gde prisutstvuyut dva nezavisimykh kanala provodimosti dlya elektronov s protivopolozhnymi spinami s sil’no raznymi konstantami relaksatsii elektronov. Sintez takikh chastits trebuet spetsial’nykh uslovii, chto ob’yasnyaet otlichie nashikh rezul’tatov ot literaturnykh dannykh.

Predskazuemost’ poyavleniya anomal’nykh voln pri umerenno nizkikh indeksakh Bendzhamina-Feira

6 May 2016 in 11:30

V.P. Ruban

Chislennoe modelirovanie nelineinoi dinamiki sluchainykh morskikh voln pri umerenno malykh indeksakh Bendzhamina-Feira i ee sravnenie s lineinoi dinamikoi (pri sovpadenii v nekotoryi moment vremeni tp prostranstvennykh Fur’e-garmonik vblizi spektral’nogo pika) ukazyvayut na vozmozhnost’ zablagovremennogo predskazaniya poyavleniya volny-ubiitsy. Esli lineinoe priblizhenie pokazyvaet nalichie v nedalekom budushchem posle tp dostatochno obshirnoi i/ili vysokoi gruppy voln, to v nelineinoi modeli anomal’naya volna pochti navernyaka formiruetsya. Period nadezhnogo prognozirovaniya ischislyaetsya neskol’kimi sotnyami volnovykh periodov, chto na praktike mozhet okazat’sya vpolne dostatochnym, naprimer, dlya izbezhaniya vstrechi sudna s gigantskoi volnoi.

Gamil’tonovy uravneniya dvizheniya vikhrevoi niti v tsilindricheski neodnorodnom boze-kondensate i ikh "solitonnye" resheniya

6 May 2016 in 11:30

V.P. Ruban

Uravnenie dvizheniya kvantovannoi vikhrevoi niti v priblizhenii lokal’noi induktsii s uchetom prostranstvennoi neodnorodnoi plotnosti boze-kondensata [Anatoly A. Svidzinsky and Alexander L. Fetter, Dynamics of a vortex in a trapped Bose-Einstein condensate, Phys. Rev. A 62, 063617 (2000)] predstavleno v variatsionnoi forme. Naideny v kvadraturakh resheniya tipa uedinennykh voln i proanalizirovana ikh zavisimost’ ot profilya ravnovesnoi plotnosti kondensata.

Josephson-effect in 3DTI and 2DTI based on HgCdTe heterostructures

22 April 2016 in 11:30

Teun Klapwijk (TU Delft)

I will report on experimental results obtained at Molenkamp’s group in Würzburg on ‘missing odd’ Shapiro steps and on emission of Josephson radiation. It is known that as a consequence of the Josephson equations, a strong relation exists between the voltage V measured across a Josephson junction and the characteristic frequency fJ =2eV/h of the current flowing in it. By applying microwave radiation steps occur at integer values of the voltage. Alternatively, ’listening’ to the rf signal radiated by the circulating supercurrent is a passive way of probing its properties. The data provide compelling evidence for the presence of a substantial 4\pi Josephson-current as would be expected from zero-enegry states. The results are available on the arxiv at: arXiv:1603.09611, arXiv:1601.08055, arXiv:1503.05591

Work done by: J.Wiedenmann, E.Bocquillon, R. Deacon, T.M.Klapwijk and various co-authors.
The research is supported by a 2014 Alexander von Humboldt prize.

Doklad po kandidatskoi dissertatsii (ruk. Lesovik G.B.)

15 April 2016 in 11:30

Suslov M.V.

Polnaya statistika perenosa kvantovykh chastits, kvantovaya metrologiya i sozdanie zaputannykh sostoyanii" V dissertatsii s pomoshch’yu formalizma pervichnogo kvantovaniya avtorom polucheny novye vyrazheniya dlya kharakteristicheskoi funktsii polnoi statistiki perenosa, uchityvayushchie energeticheskuyu zavisimost’, zavisimost’ ot vremeni, a takzhe obmennye effekty, obuslovlennye konechnym perekrytiem volnovykh paketov. V sluchae rasseyaniya dvukh fermionov poluchena subbinominal’naya statistika dlya nezaputannykh vkhodyashchikh sostoyanii, v to vremya kak zaputannye sostoyaniya mogut porozhdat’ superbinominal’nyi shum. Opisan sluchai s postoyannym napryazheniem, gde uchityvaetsya zavisimost’ rasseyaniya ot energii i konechnykh vremen izmereniya. Predlozhena skhema, soderzhashchaya uslovnye izmereniya, v kotoroi neskol’ko kubitov sluzhat detektorom v zadache o polnoi statistike perenosa. Sformulirovana i reshena zadacha scheta v terminakh problemy razlichimosti kvantovykh sostoyanii pri odnokratnom izmerenii, dayushchaya konstruktivnuyu skhemu pribora dlya kvantovogo algoritma scheta. Issledovany razlichnye vozmozhnosti pribornoi realizatsii etogo algoritma. Rassmotreny vozmozhnosti sozdaniya zaputannykh sostoyanii putem chastichnogo opredeleniya chisla proshedshikh chastits. Predlozhen novyi sposob izmereniya napryazheniya pri pomoshchi odnogo ili neskol’kikh zaryadovykh kubitov.

Kommentarii o razvitii tematiki dissertatsii.

15 April 2016 in 11:30

Lesovik G.B.

Low-energy field theory of disordered Weyl metals.

8 April 2016 in 11:30

Dmitry Bagrets (Institute for Theoretical Physics, University of Cologne, Germany)

In my talk I discuss the transport properties of disordered Weyl semimetals. In these systems, mechanisms of topological origin lead to the protection against Anderson localization, and at the same time to different types of transverse electromagnetic response -- the anomalous Hall effect (AQHE), and chiral magnetic effect (CME). I will demonstrate how an interplay of symmetry breaking and the chiral anomaly leads to the low-energy field theory containing two types of topological terms --- the Pruisken term describing AQHE and a variant of the non-Abelian Chern-Simons term responsible for CME. I will then discuss the signatures of CME in the magnetoconductance and shot noise assuming a quasi-one-dimensional geometry with a disordered Weyl semimetal nanowire being placed in the contact with two normal leads. An application of the magnetic field B along the nanowire creates the chiral 1d channels propagating parallel to B. They survive disorder averaging and the amount of them equals to the number of flux quanta piercing the nanowire. As the result, the magnetoconductance shows the crossover from quadratic to linear in B behavior while the Fano factor F is exponentially suppressed at high B as compared to F=1/3 at low B.
References: Dmitry Bagrets and Alexander Altland, PRL 114, 257201 (2015); PRB 93, 075113 (2016)

Novye fundamental’nye rezul’taty teorii atoma

25 March 2016 in 11:30

A. Dyugaev (ITF im. L.D. Landau), E. Lebedeva (IFTT)

Dlya odnovalentnykh i dvukhvalentnykh sfericheski simmetrichnykh atomov i polozhitel’nykh ionov naideny svyazi mezhdu ikh nablyudaemymi kharakteristikami, kotorye slabo zavisyat ot polozheniya atoma v tablitse Mendeleeva. Osnovnym parametrom atoma yavlyaetsya shchel’ v spektre \Delta. Ee malost’ privodit k gigantskim znacheniyam polyarizuemosti atoma \alpha = m/\Delta^2, gde m - valentnost’.

Kinematic dynamo in two-dimensional chaotic flow: the initial and final stages

18 March 2016 in 11:30

I.V. Kolokolov

V rabote izuchaetsya kinematicheskoe melkomasshtabnoe dinamo v dvumernom khaoticheskom potoke. Analiticheskie vychisleniya provodyatsya v ramkakh modeli Kraichnana-Kazantseva. Pokazano, chto rost fluktuatsii magnitnogo polya $\bm{B}$ ostanavlivaetsya na bol’shikh vremenakh v sootvetstvii s izvestnymi antidinamo-teoremami. Pri etom znachenie $\bm{B}^2$ v protsesse evolyutsii uvelichivaetsya v $\sim (R/r_d)^2=\mathrm{Pr}_m^2$ raz, gde $R$ - dlina korrelyatsii polya skorosti, $r_d$ - dissipativnyi masshtab dlya $\bm{B}$. Dlya bol’shikh znachenii magnitnogo chisla Prandtlya $\mathrm{Pr}_m$ takoe usilenie mozhet byt’ ves’ma znachimym. V rabote opredelena takzhe prostranstvennaya struktura korrelyatsionnogo tenzora fluktuatsii magnitnogo polya.

Fazovye perekhody v geksaticheskikh zhidkikh kristallakh

11 March 2016 in 11:30

Efim Kats

We resolve the old riddle related to the critical behavior of the heat capacity near the smectic A -- hexatic second order phase transition. Experiment suggests a ``large'' specific heat critical exponent $\alpha=0.5 \div 0.7$ inconsistent with the universality class for this phase transition implying the very small negative exponent $\alpha\approx-0.01$. We show that essential features of the smectic A -- hexatic phase transition can be rationalized in the framework of a theoretical model treating jointly fluctuations of the hexatic orientational and of the positional order parameters. Assuming that the positional (translational) correlation length $\xi_{tr}$ is larger than the hexatic correlation length $\xi_h$, we calculate a temperature dependence of the specific heat in the critical region near the smectic A -- hexatic phase transition. Our results are in a quantitative agreement with the calorimetric experimental data.

Dynamical phase transitions and statistics of excitations

4 March 2016 in 15:00

Alessandro Silva (SISSA, Trieste)

Dynamical phase transitions can occur in isolated quantum systems that are brought out of equilibrium by either a sudden or a gradual change of their parameters. Theoretical examples rage from the behaviour of the O(N) model in the large N limit as well as spin-model with long range interactions, both showing dynamical criticality in their prethermal steady-states. In this talk I will start by discussing the characterization of such dynamical phase transitions based on the statistics of produced excitations. I will focus both on the role of fluctuations as well as on the difference between sudden and gradual changes of the parameters. Finally, I will discuss a second type type of dynamical criticality discussed in the literature, related to the emergence of zeroes in the Loschmidt amplitude, and show that this phenomenon is much less generic and robust than standard dynamical criticality.

Anomal’nye uprugie svoistva dvumernykh neuporyadochennykh kristallov: primenenie k grafenu

4 March 2016 in 11:30

V.Yu. Kachorovskii (FTI im. A.F. Ioffe RAN), I.V. Gornyi, A.D. Mirlin

Grafen predstavlyaet soboi znamenityi primer dvumernoi kristallicheskoi membrany. Teplovye fluktuatsii membrany stremyatsya razrushit’ dal’nii poryadok v sisteme. Konkuriruyushchim effektom, blagodarya kotoromu membrana ostaetsya termodinamicheski stabil’noi, yavlyaetsya sil’noe angarmonicheskoe vzaimodeistvie mezhdu izgibnymi i prodol’nymi kolebatel’nymi modami. Angarmonicheskie effekty demonstriruyut kriticheskoe povedenie na masshtabakh bol’shikh, chem dlina Ginzburga. V chastnosti, izgibnaya zhestkost’ chistoi izolirovannoi membrany vozrastaet stepennym obrazom po mere uvelicheniya razmera sistemy: $\varkappa \propto L^{\eta}.$ V rabote izuchaetsya vliyanie besporyadka na kriticheskoe povedenie membrany. Pokazano, chto sluchainye fluktuatsii krivizny membrany, vyzvannye staticheskim besporyadkom, radikal’no menyayut kharakter skeilinga izgibnoi zhestkosti. Vyvedeny uravneniya renormgruppy (RG), opisyvayushchie izmenenie $\varkappa$ i effektivnoi sily besporyadka $b$ po mere uvelicheniya razmera sistemy. Pokazano, chto obe velichiny nemonotonno zavisyat ot $L.$ Analiz uravnenii RG pozvolyaet postroit’ kriticheskuyu krivuyu $b(\varkappa),$ razdelyayushchuyu ploskuyu i «skomkannuyu» (crumpled) fazy membrany. Geometriya membrany v okrestnosti kriticheskoi krivoi kharakterizuetsya (v opredelennom intervale masshtabov) fraktal’noi razmernost’yu. Takzhe podrobno izucheno povedenie $\varkappa$ i $b$ v ploskoi faze. Pokazano, chto gluboko v ploskoi faze besporyadok ubyvaet stepennym obrazom na masshtabakh bol’shikh, chem dlina Ginzburga, kotoraya, takim obrazom, zadaet kharakternyi masshtab ripplov (ripples) – staticheskikh izgibnykh deformatsii, eksperimental’no nablyudaemykh v izolirovannom grafene. V predele $L \to \infty $ ripply kharakterizuyutsya anomal’noi eksponentoi $2\eta$ po kontrastu s dinamicheskimi fluktuatsiyami, kotorye spadayut stepennym obrazom s pokazatelem $\eta$. Esli nachal’nyi besporyadok dostatochno velik, to sushchestvuet promezhutochnyi interval masshtabov, gde ripply ubyvayut sushchestvenno medlennee, s pokazatelem $\eta/4.$. Rezul’taty raschetov sravnivayutsya s imeyushchimisya eksperimental’nymi izmereniya parametrov ripplov v grafene. V rabote takzhe izuchaetsya povedenie membrany pod deistviem vneshnego natyazheniya. Pokazano, chto lineinyi zakon Guka narushaetsya, a imenno rastyazhenie lista grafena okazyvaetsya nelineinoi funktsiei prilozhennogo malogo natyazheniya: $\Delta L \propto \sigma^{\eta/(2-\eta)}$ i $\Delta L \propto \sigma^{\eta/(8-\eta)},$ sootvetstvenno, dlya chistoi i razuporyadochennoi membrany.

Podshchelevye sostoyaniya v neuporyadochennykh sverkhprovodnikakh s sil’nymi magnitnymi primesyami

26 February 2016 in 11:30

Ya.V. Fominov, M.A. Skvortsov

Issledovana plotnost’ sostoyanii v diffuznykh sverkhprovodnikakh s magnitnymi primesyami, podchinyayushchimisya statistike Puassona. Takim obrazom mogut byt’ opisany primesi proizvol’noi «sily», a izvestnyi sluchai bornovskikh magnitnykh primesei s gaussovoi statistikoi yavlyaetsya predel’nym sluchaem nashego rassmotreniya. Teoriya srednego polya predskazyvaet netrivial’nuyu strukturu plotnosti sostoyanii, soderzhashchuyu kontinuum kvazichastichnykh sostoyanii, a takzhe (v nekotorom diapazone parametrov) primesnuyu zonu. V priblizhenii srednego polya vse kraya spektra yavlyayutsya zhestkimi i oboznachayut chetkie granitsy mezhdu oblastyami konechnoi i nulevoi plotnosti sostoyanii. Rassmatrivaya instantony v tekhnike replichnoi sigma-modeli, my vychislyaem srednyuyu plotnost’ sostoyanii za ramkami srednepolevogo priblizheniya. Takim obrazom, my nakhodim podshchelevye sostoyaniya («khvosty»), kotorye razmyvayut kraya spektra za schet fluktuatsii potentsial’nogo (obychnye primesi) i nepotentsial’nogo (magnitnye primesi) besporyadka. Neodnorodnost’ kontsentratsii magnitnykh primesei privodit k poyavleniyu podshchelevykh sostoyanii za schet dvukh mekhanizmov: fluktuatsii para-razrushayushchego parametra (magnitnyi analog mezoskopicheskikh fluktuatsii) i fluktuatsii parametra poryadka (opredelyaemogo samosoglasovanno). V predel’nykh sluchayakh vosproizvodyatsya ranee poluchennye rezul’taty dlya podshchelevoi plotnosti sostoyanii v gryaznykh sverkhprovodnikakh s magnitnymi primesyami.

Fermi-Pasta-Ulam recurrence and modulation instability

12 February 2016 in 11:30

E.A. Kuznetsov

For the nonlinear Schrodinger equation (NLSE) we give qualitative arguments to explain the Fermi-Pasta-Ulam (FPU) recurrence which can be considered as a result of the modulation instability (MI) development. All known exact NLS solutions in the form of solitons propagating on the background of the modulationally unstable condensate show the recurrence to the condensate state after its interaction with solitons. The condensate recovers its form with the same amplitude but a different phase, as soon as solitons leave the area where they were originally. This is the analog of the FPU recurrence for the NLSE. We demonstrate, based on the NLSE integrability, that the FPU recurrence takes place for more general solution, in the form of cnoidal wave. This solution, periodic in space, can be represented as a solitonic lattice which, in one limit, for sufficiently large distance between solitons transforms into one separate soliton solution and, in the opposite limit, into the condensate. The cnoidal wave is also modulationally unstable due to soliton overlapping. In spite of the linear instability existence, at the nonlinear stage the cnoidal wave is shown to recover its form (up to constant shift in space and phase).

Metal film on substrate: Dynamics under action of ultra-short laser pulse

12 February 2016 in 11:30

V A Khokhlov, N A Inogamov, S I Anisimov, V V Zhakhovsky, K V Khishchenko

The movement of metal film placed on glass substrate under action of ultra-short laser pulse is studied with using of two-temperature hydrodynamic calculations. The features of the oscillatory modes of movement of the film on the substrate under the influence of low-energy laser pulses are investigated. Transition from film delamination from the substrate as a whole to break of a film and flying away only a forward layer of a film is tracked at growth of the enclosed energy.

Collective conductivity, criticality and reconstruction in systems with an infinite permittivity

29 January 2016 in 11:30

Serguei Brazovskii (LPTMS, CNRS & University Paris-Sud & NUST MISiS)

This talk will be devoted to conducting systems with unhindered polar deformations: ferroelectric semiconductors near the critical temperature and charge density waves (CDW) subjected to pinning and junctions constraint. For ferroelectrics, epitomized by Mott insulators in organic stack materials, we shall find access to the critical dynamics, to the creep of domain walls, and to the polarization dumping by solitons. For CDWs, we shall model the reconstruction of their current carrying states in junctions channels via dynamical and static vortex structures. For completeness, we shall recall also old stories of frequency and temperature dependence of the permittivity of CDWs under pinning and Coulomb interactions.
The presented results are based on collaborations with P. Monceau and F. Nad in experiment and with N. Kirova and A. Larkin in theory.

Instability of threeangular Abrikosov lattice at the Ginzburg-Landau parameter value κ, close to one

22 January 2016 in 11:30

Yu.N. Ovchinnikov, I.M. Sigal

V rabote issleduetsya myagkaya poperechnaya moda besshchelevykh vozbuzhdenii, svyazannaya s deformatsiei treugol’noi reshetki Abrikosova s odnim kvantom potoka v elementarnoi yacheike pri proizvol’nom znachenii parametra Ginzburga-Landau kappa. Pokazano. chto v uzkoi oblasti znachenii kappa, blizkikh k edinitse, reshetka Abrikosova s uglom F=\pi/3 mezhdu vektorami elementarnoi yacheiki neustoichiva. Spektr vozbuzhdenii rassmatrivaemoi mody pri malykh znacheniyakh impul’sa k (v k^2 priblizhenii) izotropen pri k, lezhashchem v ploskosti, perpendikulyarnoi magnitnomu polyu. Naiden interval neustoichivosti po velichine kappa.

Anisotropic characteristics of the Kraichnan direct cascade in two-dimensional hydrodynamic turbulence

15 January 2016 in 11:30

E.A. Kuznetsov, E.V. Sereshchenko

Statistical characteristics of the Kraichnan direct cascade for two-dimensional hydrodynamic turbulence are numerically studied (with spatial resolution 8192 × 8192) in the presence of pumping and viscous-like damping. It is shown that quasi-shocks of vorticity and their Fourier partnerships in the form of jets introduce an essential influence in turbulence leading to strong angular dependencies for correlation functions. The energy distribution as a function of modulus k for each angle in the inertial interval has the Kraichnan behavior, ∼k-4, and simultaneously a strong dependence on angles. However, angle average provides with a high accuracy the Kraichnan turbulence spectrum Ek = CKη2/3k−3, where η is enstrophy flux and the Kraichnan constant CK ≈ 1.3, in correspondence with the previous simulations. Familiar situation takes place for third-order velocity structure function which, as for the isotropic turbulence, gives the same scaling with respect to separation length R and η = C3ηR3, but the mean over angles and time C3 differs from its isotropic value.

Rasshcheplenie kuperovskikh par v ferromagnitnykh skvidakh

25 December 2015 in 13:00

Pavel Ioselevich

We study Josephson junctions between superconductors connected by two parallel ferromagnetic arms. For fully polarised ferromagnets, supercurrent through such a SQUID only flows via Cooper pair splitting between the differently polarised arms. The average current is suppressed, but mesoscopic fluctuations lead to a significant typical current. We calculate this current for the SFS SQUID, as well as for a SQUID with metallic arms with magnetic impurities. The latter shows an h/e periodicity in flux. The current in both systems is of fluctuational origin and is stronger for materials with low conductivity and a low superconducting gap.

Anomalous Hall effect in weakly disordered ferromagnets

18 December 2015 in 11:30

P. M. Ostrovsky

Anomalous Hall effect arises in systems with both spin-orbit coupling and magnetization. Generally, there are three mechanisms contributing to anomalous Hall conductivity: intrinsic, side jump, and skew scattering. The standard diagrammatic approach to the anomalous Hall effect is limited to computation of ladder diagrams. We demonstrate that this approach is insufficient. An important additional contribution comes from diagrams with a single pair of intersecting disorder lines. This contribution constitutes an inherent part of skew scattering on pairs of closely located defects and essentially modifies previously obtained results for anomalous Hall conductivity. We argue that this statement is general and applies to all models of anomalous Hall effect. We illustrate it by an explicit calculation for two-dimensional massive Dirac fermions with weak disorder. In this case, inclusion of the diagrams with crossed impurity lines reverses the sign of the skew scattering term and strongly suppresses the total Hall conductivity at high electron concentrations. The same mechanism for ordiary electrons with spin-orbit coupling (Bychkov-Rashba model) produces an opposite effect increasing the Hall conductivity. In the conduction band, skew scattering with crossed impurity lines is the only source of the anomalous Hall effect.

Preobrazovanie Mutara dlya obobshchennykh analiticheskikh funktsii. Vozmozhnye prilozheniya k spektral’nym zadacham.

11 December 2015 in 11:30

P.G. Grinevich, R.G. Novikov

Preobrazovaniya Darbu i Mutara yavlyayutsya odnim iz vazhnykh instrumentov v teorii integriruemykh sistem i spektral’noi teorii. Odnako, naskol’ko nam izvestno, oni vsegda deistvovali po fizicheskim peremennym. My predlagaem ispol’zovat’ preobrazovaniya Mutara po spektral’nym peremennym, chto pozvolyaet, v chastnosti issledovat’ spektral’nye zadachi s dannymi, imeyushchimi polyusa na konturakh. Spektral’nye dannye takogo tipa neizbezhno voznikayut v zadache rasseyaniya dlya dvumernogo operatora Shredingera pri odnoi energii s dostatochno bol’shim potentsialom, i do nastoyashchego vremeni ne bylo izvestno analiticheskikh metodov issledovaniya takikh zadach.

Dynamical phase transitions in electronic systems induced by ultra-fast optical pumping.

4 December 2015 in 11:30

Serguei Brazovskii (LPTMS, CNRS & University Paris-Sud & NUST MISiS)

I shall report on several studies of phase transformations in cooperative electronic systems achieved by means of a femto-second optical pumping. 1. Experiments on charge density waves recovered coherent unharmonic undulations of the order parameter, critical slowing down of the collective mode, and evolution of the particle-hole gap. The numerical modeling reproduced the dynamical phase transition, and the waves emitted by “earthquakes” from in depth annihilation events of topological defects.*) 2. The bistable switching to a “hidden” state has been achieved in a “polaronic Wigner-crystalline Mott insulator” 1T-TaS2. The theory focuses upon evolution of electrons and holes as mobile charge carriers, and the crystallized electrons modifiable by intrinsic defects.*) 3. The special case of resonance optical pumping to excitons is realized in systems with a neutral-ionic ferroelectric transition. The modeling of the quantum-coherent quasi-condensate of excitons interacting with the order parameter recovers the dynamical realization of the “excitonic insulator” state and spacio-temporal patterns with self-focusing, domains segregation, and local dynamical phase transitions.**) ----------------------------------------------------------------------------------------------- *)After collaboration with D. Mihailovic group at the Jozef Stefan Institute, Ljubljana, Slovenia. **) After collaboration with N. Kirova, LPS, University Paris-Sud, Orsay, France.

Kvazishtekkelevy sistemy. Klassifikatsiya i prilozheniya.

27 November 2015 in 11:30

V.G. Marikhin

Rassmatrivayutsya kvazishtekkelevy sistemy - obobshcheniya shtekkelevykh sistem na sluchai s magnitnym polyam. V kvantovom sluchae osobo rassmatrivayutsya uravneniya Shredingera s dopolnitel’nym kvadratichnym gamil’tonianom, gde klassifikatsiyu udaetsya dovesti do kontsa. Polucheny novye kvazishtekkelevy sistemy s 3-mya stepenyami svobody.

Deistvie kak invariant preobrazovanii Beklunda lagranzhevykh sistem.

27 November 2015 in 11:30

V.G. Marikhin

My stroim obshchuyu teoriyu preobrazovanii Beklunda lagranzhevykh sistem, trebuya, chtoby deistvie pri primenenii etikh preobrazovanii sokhranyalos’.Obsuzhdayutsya izvestnye preobrazovaniya Beklunda dlya klassicheskikh solitonnykh uravnenii s tochki zreniya etogo podkhoda. Polucheno novoe preobrazovanie Beklunda dlya uravneniya Tsitseiki.

Spatial Equation for Water Waves

20 November 2015 in 11:30

A.I. Dyachenko and V.E. Zakharov

We derive spatial Hamiltonian equation for the gravity waves on the deep water. The equation is very suitable for laboratry experiments in a Wave Tank.

Charge relaxation resistance in the cotunneling regime of multi-channel Coulomb blockade: Violation of Korringa-Shiba relation

13 November 2015 in 11:30

I.S. Burmistrov

We study the low frequency admittance of a small metallic island coupled to a gate electrode and to a massive reservoir via a multi channel tunnel junction. The ac current is caused by a slowly oscillating gate voltage. We focus on the regime of inelastic cotunneling in which the dissipation of energy (the real part of the admittance) is determined by two-electron tunneling with creation of electron-hole pairs on the island. We demonstrate that at finite temperatures but low frequencies the energy dissipation is ohmic whereas at zero temperature it is super-ohmic. We find that (i) the charge relaxation resistance (extracted from the real part of the admittance) is strongly temperature dependent, (ii) the imaginary and real parts of the admittance do not satisfy the Korringa-Shiba relation. At zero temperature the charge relaxation resistance vanishes in agreement with the recent zero temperature analysis [M. Filippone and C. Mora, Phys. Rev. B86, 125311 (2012) and P. Dutt, T. L. Schmidt, C. Mora, and K. Le Hur, Phys. Rev. B 87, 155134 (2013)].

Pravila sootvetstviya v atomnoi fizike. Primesnye atomy v zhidkom gelii.

6 November 2015 in 11:30

A.M. Dyugaev, E.V. Lebedeva

V atomnoi fizike polezno vvesti ponyatie faktora zapolneniya, svyazannogo s pervym ionizatsionnym potentsialom. Analiticheskoe prodolzhenie etogo faktora s tselykh tochek pozvolyaet svyazat’ svoistva odnovalentnykh atomov (Li-Cs) s vodorodom. Primesnye atomy tipa Cs v zhidkom gelii formiruyut gigantskie puzyr’kovye ob’ekty s ob’emom ~10000 v atomnykh edinitsakh.

Chislennoe issledovanie statistiki urovnei i volnovykh funktsii na sluchainykh regulyarnykh grafakh s besporyadkom

6 November 2015 in 11:30

Konstantin Tikhonov

Interes k zadache ob odnochastichnoi lokalizatsii na sluchainom regulyarnom grafe (RRG) v poslednee vremya vozros v svyazi s problemoi mnogochastichnoi lokalizatsii (MBL). Kachestvenno, MBL mozhno ponimat’ kak Andersonovskuyu lokalizatsiyu v prostranstve Sleterovskikh determinantov, kotorye igrayut rol’ uzlov v neoporyadochennoi pryzhkovoi modeli. Tak kak struktura Fokovskogo prostranstva ierarkhichna, sootvetstvuyushchaya reshetka napominaet sluchainyi regulyarnyi graf. V etoi rabote my izuchaem Andersonovskii perekhod v ansamble RRG s besporyadkom s pomoshch’yu tochnoi chislennoi diagonalizatsii. My pokazyvaem, chto poluchennaya kartina perekhoda na RRG sovmestima s sushchestvuyushchei teoriei, s usloviem pravil’noi interpretatsii poluchennykh rezul’tatov i ucheta effektov konechnosti razmera grafa. Nash analiz snimaet protivorechie mezhdu imeyushchimisya teoreticheskimi rezul’tatami i chislennymi issledovaniyami drugikh avtorov.

Exactly solvable models of String Theory and Dubrovin-Saito Flat structures

30 October 2015 in 11:30

A. Belavin, Ya. Kononov

It was shown many years ago for $2d$ topological Conformal field theory and more recently for the non-critical String theory that a number of models of these two types can be exactly solved using their connection with the Frobenius manifold (FM) structure introduced by Dubrovin. More precisely these models are connected with a special case of FMs, so called Saito Frobenius manifolds. In this talk we explore the connection of the models of TCFT and non-critical String theory with SFM. The crucial point for obtaining an explicit expression for the correlators is finding the flat coordinates of SFMs as functions of the parameters of the deformed singularity. We suggest a direct way to find the flat coordinates, using the integral representation for the solutions of Gauss-Manin system connected with the corresponding SFM for a simple singularity. Also, we address the possible generalization of our approach for the models investigated by Gepner models which are ${SU(N)_k}/({SU(N-1)_{k+1} \times U(1)})$ Kazama-Suzuki theories .

Geometricheskii transport v kvantovom effekte Kholla

23 October 2015 in 11:30

Pavel Vigman

Khorosho izvestno chto provodimost’ Kholla kvantuetsya s vysokoi tochnost’yu. Sushchestvuyut li drugie transportnye koeffitsienty, kvantuyushchiesya s takoi zhe tochnost’yu? Okazyvaetsya, chto takikh koeffitsientov kak minimum dva. Oni svyazany s transportom, vyzvannym izmeneniem geometricheskoi formy elektronnoi zhidkosti. Po rabote: S. Klevtsov, P. Wiegmann: Phys. Rev. Lett. 115: 086801 (2015)

Blossom Belief Propagation: Exact Algorithm for Minimum Weight Perfect Matching

16 October 2015 in 11:30

Michael (Misha) Chertkov (New Mexico Consortium & Skoltech)

Max-product Belief Propagation (BP) is a popular message-passing algorithm for computing a Maximum-A-Posteriori (MAP) assignment over a distribution represented by a Graphical Model (GM). It has been shown that BP can solve a number of combinatorial optimization problems including minimum weight matching, shortest path, network flow and vertex cover under the following common assumption: the respective Linear Programming (LP) relaxation is tight, i.e., no integrality gap is present. However, when LP shows an integrality gap, no model has been known which can be solved systematically via sequential applications of BP. In this talk, I describe construction of the first such algorithm, coined Blossom-BP, for solving the minimum weight matching problem over arbitrary graphs. Each step of the sequential algorithm requires applying BP over a modified graph constructed by contractions and expansions of blossoms, i.e., odd sets of vertices. Our scheme guarantees termination in O(n^2) of BP runs, where n is the number of vertices in the original graph. In essence, the Blossom-BP offers a distributed version of the celebrated Edmonds' Blossom algorithm by jumping at once over many sub-steps with a single BP. Moreover, our result provides an interpretation of the Edmonds' algorithm as a sequence of LPs. This is a joint work with Sungsoo Ahn, Sejun Park and Jinwoo Shin (Korean Institute of Science and Technology).

Development of high vorticity structures in incompressible 3D Euler equations

9 October 2015 in 15:00

D.S. Agafontsev, A.A. Maylybaev, E.A. Kuznetsov

We present in details our numerical scheme and more of our numerical results, on which our previous talk "Folding of vorticity field as a route to the Kolmogorov spectrum" was based.

“Polzuchaya” provodimost’, relaksatsiya i fluktuatsii v sisteme podvizhnykh metallicheskikh granul

9 October 2015 in 11:30

V.V. Sivak, A.S. Ioselevich

My rassmatrivaem nestatsionarnuyu sistemu provodnikov, soprotivleniya mezhdu kotorymi ispytyvayut sil’nye fluktuatsii vo vremeni. Transport mezhdu paroi sosednikh provodnikov opredelyaetsya temi momentami, kogda sootvetstvuyushchee soprotivlenie anomal’no malo (provodniki “kasayutsya drug druga”). V takie momenty voznikaet “proboi” i zaryad legko peretekaet mezhdu paroi soprikosnuvshikhsya provodnikov. Protsess perenosa zaryada za schet proboev, voznikayushchikh v sluchainye momenty v sluchainykh mestakh, my nazvali polzuchei provodimost’yu. My rassmatrivaem kak trekhmernye, tak i nizkorazmernye massivy provodnikov i issleduem provodimost’ sistemy, rastekanie zaryada, pervonachal’no sosredotochennogo na odnom provodnike, a takzhe fluktuatsii zaryadov i elektricheskikh polei i ikh prostranstvenno-vremennuyu korrelyatsiyu. Obsuzhdayutsya vozmozhnye realizatsii modeli v kolloidnykh rastvorakh i sistemakh metallicheskikh sharikov, soedinennykh deformiruemymi polimernymi molekulami.

Thermal transport in disordered one-dimensional spin chains

9 October 2015 in 11:30

Igor Poboiko, Mikhail Feigel'man

We study one-dimensional anisotropic XY-Heisenberg spin-1/2 chain with weak random fields hziSzi by means of Jordan-Wigner transformation to spinless Luttinger liquid with disorder and bosonization technique. First we investigate phase diagram of the system in terms of dimensionless disorder γ=⟨h2⟩/J2≪1 and anisotropy parameter Δ=Jz/Jxy and find the range of these parameters where disorder is irrelevant in the infrared limit and spin-spin correlations are described by power laws. Then we use the diagram technique in terms of plasmon excitations to study low-temperature behavior of heat conductivity κ and spin conductivity σ in this power-law phase. The obtained Lorentz number L≡κ/σT differs from the value derived earlier by means of memory function method. We argue also that in the studied region inelastic scattering is strong enough to suppress quantum interference in the low-temperature limit.

Folding of vorticity field as a route to the Kolmogorov spectrum

2 October 2015 in 11:30

E.A. Kuznetsov, D.S. Agafontsev and A.A. Mailybaev

This work is aimed for understanding nonlinear mechanisms at early stages of turbulence, when the flow is not yet affected by viscosity. Based on numerical simulations of the 3D incompressible Euler equations with generic large-scale initial conditions, we show the exponential growth of vorticity developing as thin pancake structures with the vorticity maximum related to the pancake width by the Kolmogorov-type power law, $\omega_max \sim \ell^{-2/3}$. This self-similar dependence is explained as a consequence of the folding for vorticity field obtained from the asymptotic analysis. We argue that increasing with time number of such structures leads to formation of the Kolmogorov energy spectrum observed numerically in a fully inviscid flow, with no tendency towards finite-time blowup.

Sverkhtekuchaya plotnost’ sil’no neuporyadochennykh sverkhprovodnikov i ikh anomal’noe povedenie pri nizkikh temperaturakh i sil’nykh magnitnykh polyakh.

25 September 2015 in 11:30

M. V. Feigel’man

Doklad budet sostoyat’ iz dvukh chastei. V pervoi iz nikh budet pokazano, na osnove sovmestnoi s L.B.Ioffe raboty [1], chto sverkhprovodniki s psevdoshchel’yu obladayut anomal’noi zavisimost’yu sverkhtekuchei plotnosti \rho_s ot velichiny sverkhprovodyashchei shcheli \Delta: \rho_s ~ \Delta^2. Pokhozhee povedenie bylo nedavno nablyudeno [2]. Vo vtoroi chasti doklada ya pokazhu, kak mozhno ob’yasnit’ shiroko izvestnoe dlya sil’no gryaznykh sverkhprovodnikov anomal’noe povedenie verkhnego kriticheskogo polya H_c2(T) pri nizkikh temperaturakh, ispol’zuya nedavnii eksperimental’nyi rezul’tat [3] o nalichii perekhoda Berezinskogo-Kosterlitsa-Taulesa v sluchae sverkhprovodyashchei plenki v sil’nom magnitnom pole i rezul’taty izmereniya kriticheskogo toka kak funktsii magnitnogo polya v predele ochen’ nizkikh temperaturakh [4].
[1] M. V. Feigel'man, L. B. Ioffe arXiv:1509.05138, Phys Rev B, accepted.
[2] D. Sherman et al, Nature Phys. (2015)
[3] S. Misra, L. Urban, M. Kim, G. Sambandamurthy, and A. Yazdani, Phys. Rev. Lett. 110, 037002 (2013)
[4] J.Seidemann et al, unpublished (Master diploma thesis, Grenoble 2013).

Primitivnye potentsialy s prilozheniyami k teorii integriruemoi turbulentnosti.

25 September 2015 in 11:30

V.E. Zakharov

Kvantovyi raspad sverkhtokovogo sostoyaniya i sobstvennaya emkost’ Dzhozefsonovskikh perekhodov za ramkami tunnel’nogo priblizheniya

18 September 2015 in 11:30

Daniil Antonenko

A nondissipative supercurrent state of a Josephson junction is metastable with respect to the formation of a finite-resistance state. This transition is driven by fluctuations, thermal at high temperatures and quantum at low temperatures. We evaluate the life time of such a state due to quantum fluctuations in the limit when the supercurrent is approaching the critical current. The decay probability is determined by the instanton action for the superconducting phase difference across the junction. At low temperatures, dynamics of the phase is massive and is determined by the effective capacitance, which is a sum of the geometric and intrinsic capacitance of the junction. We model the central part of the Josephson junction either by an arbitrary short mesoscopic conductor described by the set of its transmission coefficients, or by a diffusive wire of an arbitrary length. The intrinsic capacitance can generally be estimated as $C_* \sim G/E_g$, where $G$ is the normal-state conductance of the junction and $E_g$ is the proximity minigap in its normal part. The obtained capacitance is sufficiently large to qualitatively explain hysteretic behavior of the current-voltage characteristic even in the absence of overheating.

Observation of half-quantum vortices in superfluid 3He

18 September 2015 in 11:30

S. Autti, V.V. Dmitriev, V.B. Eltsov, J. Makinen, G.E. Volovik, A.N. Yudin, V.V. Zavjalov

Recently in Kapitza Institute a new phase of the superfluid 3He was reported to exist in the aerogel-like nafen structure - the so-called polar phase. As distinct from the other phases - the chiral superfluid 3He-A with Weyl nodes and the fully gapped topological 3He-B with Dirac nodes on the surface - the polar phase has Dirac nodal line in bulk and dispersionless band of Andreev-Majorana fermions on the surface. Being the spin-triplet superfluid with equal-spin pairing the polar phase can support an exotic object - the half-quantum vortex (HQV). Originally the HQVs have been predicted to exist in the Weyl superfluid 3He-A in 1976, but still they have not been observed there: unfavorable combination of spin-orbit and magnetic anisotropy effects on the orientation of the order parameter did not allow to stabilize these vortices in bulk 3He-A under rotation. In nafen, the nearly parallel aerogel strands pin the orbital part of the order parameter of the polar phase. As a result, if the magnetic field is absent or is oriented parallel to nafen strands, the half-quantum vortices win over the conventional single-quantum vortices.
If HQVs are formed in rotation and then the field is tilted with respect to the strands, one expects that the spin-orbit interaction would induce the formation of the topological solitons between the neighboring HQVs providing the peculiar satellite peak in the NMR spectrum. We used this theoretical prediction to stabilize and identify the HQVs in the Helsinki rotated cryostat. For that we cool down a sample of nafen through transition temperature to the polar phase in rotation up to 2.75 rad/s without magnetic field. Then the field is switched on, and in the tilted field we observe a satellite peak in the NMR spectrum. The dependence of the satellite on the rotation velocity, temperature and the field orientation is in agreement with the predictions. If cool-down occurs with the field applied in the transverse direction, no satellite eak is observed. This demonstrates that the single-quantum vortices are formed instead, which have no NMR signatures. in such arrangement these vortices win over the HQVs as expected.

On mathematical and computational problems of genomics: from sequencing to population structure

11 September 2015 in 15:00

Vladimir Shchur (Sanger Institute, Cambridge, UK)

Genomics is a young research area in bioinformatics. It has appeared recently due to a significant decrease in the value of DNA sequencing. This drop in sequencing prices led to a rapid growth of the amount of genomic data. Mathematical and computational analysis is of a great importance at all stages of the genomic study: from the identification of variable sites (such as mutations, insertions and deletions) to the study of the population structure. We will discuss what kind of major mathematical and computational problems arise in genomics and will introduce their most basic models and concepts.

ALGEBRA URAVNENIYa OTRAZhENII (Struktura, predstavleniya, prilozheniya)

11 September 2015 in 11:30

P.A. Saponov (IFVE & NIU VShE)

Algebra uravneniya otrazhenii vpervye poyavilas’ v teorii integriruemykh sistem s granitsei, a zatem nashla shirokoe primenenie v teorii kvantovykh grupp i algebr i nekommutativnoi geometrii. Ya sobirayus’ sdelat’ (po vozmozhnosti) populyarnyi obzor nekotorykh ee strukturnykh svoistv, ee dostatochno netrivial’noi teorii predstavlenii i prilozhenii k problemam kvantovaniya nelineinykh skobok Puassona. (Po materialam doktorskoi dissertatsii)

Super compact equation for water waves

4 September 2015 in 11:30

A.I. Dyachenko, D.I. Kachulin, V.E. Zakharov

Uravneniya Eilera na matritse 3x3 i ploskie krivye.

5 June 2015 in 11:30

Konstantin Aleshkin (MGU)

Branch cuts of Stokes wave: numerical and analytical results.

5 June 2015 in 11:30

S.A. Dyachenko, P.M. Lushnikov, and A.O. Korotkevich

Complex analytical structure of Stokes wave for two-dimensional potential flow of the ideal incompressible fluid with free surface and infinite depth is analyzed. Stokes wave is the fully nonlinear periodic gravity wave propagating with the constant veloci1ty. Simulations with the quadruple (32 digits) and variable precisions (more than 200 digits) are performed to find Stokes wave with high accuracy and study the Stokes wave approaching its limiting form with 120 degrees angle on the crest. A conformal map is used which maps a free fluid surface of Stokes wave into the real line with fluid domain mapped into the lower complex half-plane. The Stokes wave is fully characterized by the complex singularities in the upper complex half-plane. These singularities are addressed by rational (Pad\'e) interpolation of Stokes wave in the complex plane. Convergence of Pad\'e approximation to the density of complex poles with the increase of the numerical precision and subsequent increase of the number of approximating poles reveals that the only singularities of Stokes wave are branch cuts. We identified that this singularity is the square-root branch point. That branch cut defines the second sheet of the Riemann surface if we cross the branch cut. Second singularity is also the square-root and located in that second (nonphysical) sheet of the Riemann surface in the lower half-plane. Crossing corresponding branch cut in second sheet one arrives to the third sheet of Riemann surface with another singularity etc. As the nonlinearity increases, all singularities approach the real line forming the classical Stokes solution (limiting Stokes wave) with the branch point of power 2/3.

Novyi kvantovyi mekhanizm provodimosti v dvukhsloinykh geterostrukturakh

22 May 2015 in 11:30

S.V. Iordanskii

Topology of Dirac lines and nexus in graphite

8 May 2015 in 11:30

T.T. Heikkila and G.E. Volovik

We consider the Z_2 topology of the Dirac lines - lines of band intersection - in graphite. Four lines (three with topological charge N_1=1 each and one with N_1=-1) merge near the H-point and annihilate due to summation law 1+1=0. The merging point is similar to the real-space nexus, the analog of Dirac monopole at which the Z_2 strings terminate.

Giant mesoscopic fluctuations of the elastic cotunneling thermopower of a single-electron transistor

24 April 2015 in 11:30

A. S. Vasenko, Denis M. Basko, F. W. J. Hekking (University Grenoble Alpes, CNRS, LPMMC)

We study the thermoelectric transport of a small metallic island weakly coupled to two electrodes by tunnel junctions. In the Coulomb blockade regime, in the case when the ground state of the system corresponds to an even number of electrons on the island, the main mechanism of electron transport at the lowest temperatures is elastic cotunneling. In this regime, the transport coefficients strongly depend on the realization of the random impurity potential or the shape of the island. Using random-matrix theory, we calculate the thermopower and the thermoelectric kinetic coefficient and study the statistics of their mesoscopic fluctuations in the elastic cotunneling regime. The fluctuations of the thermopower turn out to be much larger than the average value.
[Phys. Rev. B 91, 085310 (2015)]

Generatsiya zavikhrennosti poverkhnostnymi volnami

17 April 2015 in 11:30

S.S. Vergeles, V.V. Lebedev

Superconductor-insulator transitions: Phase diagram and magnetoresistance

27 March 2015 in 11:30

I.S. Burmistrov, I.V. Gornyi, A.D. Mirlin

Influence of disorder-induced Anderson localization and of electron-electron interaction on superconductivity in two-dimensional systems is explored. We determine the superconducting transition temperature Tc, the temperature dependence of the resistivity, the phase diagram, as well as the magnetoresistance. The analysis is based on the renormalization group (RG) for a nonlinear sigma model. Derived RG equations are valid to the lowest order in disorder but for arbitrary electron-electron interaction strength in particle-hole and Cooper channels. Systems with preserved and broken spin-rotational symmetry are considered, both with short-range and with long-range (Coulomb) interaction. In the cases of short-range interaction, we identify parameter regions where the superconductivity is enhanced by localization effects. Our RG analysis indicates that the superconductor-insulator transition is controlled by a fixed point with a resistivity Rc of the order of the quantum resistance Rq = h/4e2. When a transverse magnetic field is applied, we find a strong nonmonotonous magnetoresistance for temperatures below Tc.

Dinamika spina v nakopitelyakh i sistematicheskie oshibki v poiskakh EDM

20 March 2015 in 11:30

N. Nikolaev, A. Saleev i F. Ratmann

Budet opisan teoreticheskii i eksperimental’nyi progress v ponimanii sistematicheskikh ogranichenii v poiskakh EDM zaryazhennykh chastits v nakopitelyakh. V opytakh na uskoritele COSY v Yulikhe chastota pretsessii spina deitrona izmerena s desyat’ desyatichnymi znakami — eto rekordnaya dlya nakopitelei tochnost’. Predlozhennym nami sposobom takzhe vpervye napravlenie osi stabil’nogo spina izmereno s sem’yu znachashchimi tsiframi, na chetyre poryadka luchshe, chem eto bylo vozmozhno ranee.

Novyi mekhanizm rasseyaniya elektronov v magnitnom pole v sostoyanii s volnoi plotnosti v usloviyakh neideal’nogo nestinga

13 March 2015 in 11:30

P.D. Grigor’ev

V sostoyanii s volnoi zaryadovoi ili spinovoi plotnosti v usloviyakh neideal’nogo nestinga chast’ elektronnykh sostoyanii ostaetsya na urovne Fermi, chto sokhranyaet metallicheskuyu provodimost’ obraztsa. Odnako poverkhnost’ Fermi elektronov provodimosti v takom sostoyanii sil’no otlichaetsya ot iskhodnoi, potomu chto rasseyanie na vektor volny plotnosti privodit k perestroike poverkhnosti Fermi. Obychno eto soprovozhdaetsya vozniknoveniem novykh chastot magnitnykh kvantovykh ostsillyatsii, sootvetstvuyushchikh perestroennoi poverkhnosti Fermi. Odnako, v sil’nom magnitnom pole voznikaet magnitnyi proboi, kotoryi mozhet vosstanovit’ dvizhenie elektronov po traektoriyam, sootvetstvuyushchim iskhodnoi poverkhnosti Fermi. Eto proiskhodit iz-za togo, chto rasstoyanie po energii mezhdu starymi i novymi elektronnymi traektoriyami okazyvaetsya malym, poryadka potentsiala rasseyaniya na volne plotnosti, to est’ poryadka energeticheskoi shcheli volny plotnosti. Pri etom veroyatnost’ elektronov dvigat’sya vdol’ staroi ili novoi poverkhnosti Fermi eksponentsial’no zavisit ot velichiny etoi shcheli. Poetomu prostranstvennye fluktuatsii parametra poryadka volny plotnosti privodyat k prostranstvennym fluktuatsiyam veroyatnosti magnitnogo proboya, i v itoge k dopolnitel’nomu rasseyaniyu elektronov. Pri vysokoi kontsentratsii neodnorodnostei volny plotnosti etot novyi mekhanizm rasseyaniya elektronov provodimosti mozhet okazat’sya dostatochno sil’nym: sil’nee, chem rasseyanie na primesyakh. Etot mekhanizm mozhet privodit’ k neobychnym effektam, takim kak sil’noe nemonotonnoe magnitosoprotivlenie, ili inversiya fazy magnitnykh kvantovykh ostsillyatsii. Imenno eto nablyudaetsya v razlichnykh organicheskikh metallakh, naprimer, v a-(BEDT-TTF)2KHg(SCN)4. Obsuzhdaetsya takzhe vozmozhnost’ ispol’zovaniya etogo mekhanizma rasseyaniya dlya izmereniya fluktuatsii parametra poryadka volny plotnosti v vysokotemperaturnykh sverkhprovodnikakh.

Raznostnoe uravnenie Shredingera i kvazisimmetricheskie mnogochleny

6 March 2015 in 11:30

A.B. Shabat

Na model’nom uravnenii Shredingera s del’taobraznym potentsialom obsuzhdayutsya sushchestvennye otlichiya obratnoi zadachi rasseyaniya na vsei osi ot sluchaya poluosi. Ispol’zuetsya pri etom ekvivalentnost’ rassmatrivaemoi model’noi zadachi diskretnoi tsepochke uravnenii s vzaimodeistviem blizhaishikh sosedei dostatochno obshchego vida. Ustanavlivayutsya takzhe yavnye formuly dlya funktsii Grina uravnenii Shredingera s del’taobraznymi potentsialami i issleduyutsya svoistva etikh funktsii Grina.

Vozniknovenie bol’shikh tokov v dvukhsloinykh geterostrukturakh

20 February 2015 in 11:30

S.V. Iordanskii

Localization-delocalization transition in the distribution of inertial particles in wall-bounded random flow

13 February 2015 in 11:30

S. Belan, A. Chernykh and G. Falkovich

Turbophoresis is the tendency of particles to migrate in the direction of minima of turbulence intensity (say, a wall). It was recently suggested that the sign of turbophoresis can be actually opposite, so that particles agitated by turbulent fluid fluctuations go away from minima of fluctuations intensity if they are inertial enough. That means localization-delocalization transition upon the change of inertia: particles with small inertia go to a minimum of turbulence, while sufficiently inertial particles escape to infinity. We consider the motion of inertial particles near a wall in the case of inelastic particle-wall collisions. The phase diagram for the transition in the inertia-elasticity plane is found. If the restitution coefficient of particle velocity is smaller than some critical value, then the inelastic collapse occurs: the particles are localized near the wall for any inertia. The theoretical predictions are in a good agreement with the results of direct numerical simulations.

Landau theory for helical nematic phases

6 February 2015 in 11:30

E.I. Kats and V.V. Lebedev

We propose Landau phenomenology for the phase transition from the conventional nematic into the conical helical orientationally non-uniform structure recently identified in liquid crystals formed by ``banana''-shaped molecules. The mean field predictions are mostly in agreement with experimental data. Based on the analogy with de Gennes model, we argue that fluctuations of the order parameter turn the transition to the first order phase transition rather than continuous one predicted by the mean-field theory. This conclusion is in agreement with experimental observations. We discuss the new Goldstone mode to be observed in the low-temperature phase.

Effects of the quark-gluon plasma in pp, pA and AA-collisions

30 January 2015 in 11:30

B.G. Zakharov

I review my recent results on physics of pp, pA and AA collisions at RHIC-LHC energies. In the first part of the talk I discuss the electromagnetic response of the quark-gluon plasma in AA-collisions for a realistic space-time evolution of the plasma fireball. We demonstrate that for a realistic electric conductivity the electromagnetic response of the plasma is in a quantum regime when the induced electric current does not generate a classical electromagnetic field as was assumed previously. It can only lead to a rare emission of single photons. In the second part of my talk I discuss jet quenching in pp and pA collisions in the scenario with formation of a mini quark-gluon plasma. We find a significant suppression effect. For light hadrons at p_{T}\sim 10 GeV we obtained the reduction of the spectra by \sim [20-30,25-35,30-40]% in pp collisions at \sqrt{s}=[0.2, 2.76,7] TeV. We discuss how jet quenching in pp collisions may change the predictions for the nuclear modification factors in AA collisions for light and heavy flavors. We also give predictions for modification of the photon-tagged and inclusive jet fragmentation functions in high multiplicity pp events.

Gaussov variatsionnyi anzats v probleme anomal’nykh morskikh voln: sravnenie s pryamym chislennym modelirovaniem

23 January 2015 in 11:30

V.P. Ruban

Nelineinaya dinamika koso orientirovannogo paketa voln na morskoi poverkhnosti issleduetsya analiticheski i chislenno dlya razlichnykh nachal’nykh znachenii parametrov paketa v svyazi s problemoi t. n. voln-ubiits (rogue waves). V ramkakh gaussova variatsionnogo anzatsa, primenennogo k sootvetstvuyushchemu (1+2D)-mernomu giperbolicheskomu nelineinomu uravneniyu Shredingera, vyvedena uproshchennaya lagranzheva sistema differentsial’nykh uravnenii, opisyvayushchaya evolyutsiyu koeffitsientov deistvitel’noi i mnimoi kvadratichnykh form, prisutstvuyushchikh v gaussiane. Eta model’ daet polukolichestvennoe opisanie protsessa nelineinoi prostranstvenno-vremennoi fokusirovki - odnogo iz naibolee veroyatnykh mekhanizmov formirovaniya anomal’nykh voln v sluchainykh volnovykh polyakh. Sistema integriruetsya v kvadraturakh, chto pozvolyaet luchshe ponyat’ kachestvennye razlichiya mezhdu lineinym i nelineinym rezhimami fokusirovki volnovogo paketa. Provoditsya sravnenie predskazanii gaussovoi modeli s rezul’tatami pryamogo chislennogo modelirovaniya polnost’yu nelineinykh dlinnogrebnevykh voln.

Wilson fermion doubling phenomenon on irregular lattice: the similarity and difference with the case of regular lattice

16 January 2015 in 11:30

S.N. Vergeles

It is shown that the Wilson fermion doubling phenomenon on irregular lattices (simplicial complexes) does exist. This means that the irregular (not smooth) zero or soft modes exist. The statement is proved on 4 Dimensional lattice by means of the Atiyah-Singer index theorem, then it is extended easily into the cases D < 4. But there is a fundamental difference between doubled quanta on regular and irregular lattices: in the latter case the propagator decreases exponentially. This means that the doubled quanta on irregular lattice are "bad" quasiparticles.

Effective actions, nonrelativistic diffeomorphism invariance and some applications

16 January 2015 in 11:30

Oleg Andreev

I will discuss certain aspects of the recently proposed notion of nonrelativistic diffeomorphism invariance. In particular, examples of invariant effective actions, extended gauge symmetry, Horava-Lifshitz gravity and some applications to the theory of quantum Hall effect.

N=2 supergravitatsiya v AdS4, lokalizatsiya i AdS4/CFT3 sootvetstvie. (rabota v progresse s Daniel Jafferis, Thomas Dumitrescu)

19 December 2014 in 11:30

B. Mukhametzhanov

Soglasno AdS_4\CFT_3 sootvetstviyu M-teoriya na AdS_4 \times X_7 dual’na ABJM teorii na trekhmernoi sfere. Statisticheskaya summa v ABJM teorii izvestna tochno. Tsel’yu dannoi raboty yavlyaetsya izuchenie N=2 supergravitatsii v AdS_4, yavlyayushcheisya nizkoenergeticheskim predelom M-teorii. V dannoi rabote N=2 supergravitatsiya formuliruetsya s pomoshch’yu superkonformnykh metodov. Dalee dlya polucheniya statsummy v supergravitatsii primenyaetsya teorema o lokalizatsii. V predele t-Khoofta bol’shikh N otvet sovpadaet s rezul’tatami v ABJM teorii.

Spin susceptibility and tunneling density of states in quantum dots

19 December 2014 in 11:30

Azat Sharafutdinov

Detal’no issledovany staticheskie prodol’nye i dinamicheskie poperechnye spinovye vospriimchivosti v kvantovykh tochek i nanochastitsakh v ramkakh gamil’toniana, kotoryi yavlyaetsya rasshireniem universal’nogo gamil’toniana na sluchai odnoosnogo anizotropnogo obmena. Dlya predel’nykh sluchaev obmennogo vzaimodeistviya tipa Izinga i Geizenberga, izucheno kak fluktuatsii odnochastichnykh urovnei energii vliyayut na stounerovskuyu neustoichivost’ v kvantovykh tochkakh. Okazyvaetsya, chto v rezhime sil’nykh fluktuatsii zadacha svoditsya k zadache o statistike ekstremumov nekotorogo gaussovskogo protsessa. Dokazano, chto, nesmotrya na sil’nye fluktuatsii odnochastichnykh urovnei energii, spinovaya vospriimchivost’ i vse ee momenty raskhodyatsya odnovremenno v tochke, kotoraya opredelyaetsya s pomoshch’yu standartnogo kriteriya neustoichivosti Stounera s uchastiem tol’ko srednego rasstoyanie mezhdu odnochastichnymi urovnyami energii. Takzhe issledovano povedenie tunnel’noi plotnosti sostoyanii v sluchae anizotropnogo obmena. Pokazano, chto predskazannoe v rabote Y. Gefen, M. Kiselev, PRL96, 066805 (2006) nemonotonnoe (s dvumya maksimumami i minimumom) povedenie tunnel’noi plotnosti sostoyanii, kak funktsii energii, na samom dele ne sushchestvuet. Podrobno, nashi rezul’taty predstavleny v sleduyushchikh rabotakh: 1. D.S. Lyubshin, A.U. Sharafutdinov, I.S. Burmistrov, «Statistics of spin fluctuations in quantum dots with Ising exchange», Phys. Rev. B 89, 201304(R ) (2014). 2. A.U. Sharafutdinov, D.S. Lyubshin, I.S. Burmistrov, «Spin fluctuations in quantum dots», Phys. Rev. B 90, 195308 (2014). 3. A.U. Sharafutdinov, I.S. Burmistrov, «Tunneling density of states in quantum dots with anisotropic exchange», gotovitsya k otpravke v pechat’.

Dva tipa nechetnoi po chastote sverkhprovodimosti

12 December 2014 in 11:30

Ya.V. Fominov

Printsip Pauli privodit k antisimmetrii anomal’noi funktsii Grina, opisyvayushchei sverkhprovodimost’, pri perestanovke koordinat elektronov. Polnyi nabor koordinat vklyuchaet v sebya, pomimo prostranstvennykh koordinat i proektsii spinov, takzhe i vremya. V matsubarovskom predstavlenii funktsiya Grina, v printsipe, mozhet byt’ nechetnoi po chastote, chto bylo otmecheno Berezinskim. Zatem teoreticheski bylo pokazano, chto nechetnye po chastote sverkhprovodyashchie korrelyatsii mogut voznikat’ v neodnorodnykh kontaktakh sverkhprovodnikov i ferromagnetikov kak subdominantnye komponenty vblizi granitsy. Neobychnoi osobennost’yu takogo sostoyaniya yavlyaetsya "paramagnitnyi" (protivopolozhnyi obychnomu) znak svyazi mezhdu vektornym potentsialom i sverkhtokom (anomal’nyi effekt Meissnera). V ob’emnom sverkhprovodnike takoe sostoyanie bylo by neustoichivym. Nedavno neskol’kimi gruppami byla predlozhena vozmozhnost’ realizatsii ob’emnogo nechetnogo po chastote sverkhprovodyashchego sostoyaniya s obychnym diamagnitnym meissnerovskim otklikom. V doklade budut obsuzhdeny fizicheskie sledstviya takogo predpolozheniya.

Effektivnaya provodimost’ pryamougol’nogo i geksagonal’nogo zamoshchenii ploskosti

12 December 2014 in 11:30

L.Yu. Barash, I.M. Khalatnikov

Effektivnaya provodimost’ dvumernykh periodicheskikh zamoshchenii ploskosti mnogougol’nikami naidena kak v ramkakh teorii vozmushchenii, tak i chislenno. Polucheny pravila postroeniya diagramm teorii vozmushchenii dlya effektivnoi provodimosti zamoshchenii ploskosti pri ispol’zovanii kosougol’nykh koordinat. Provedeny raschety dlya trekhtsvetnogo geksagonal’nogo zamoshcheniya ploskosti. Chislennyi raschet pozvolyaet opredelit’ effektivnuyu provodimost’ s vysokoi tochnost’yu kak v oblasti primenimosti teorii vozmushchenii, tak i v sluchayakh, kogda provodimosti komponent sushchestvenno razlichny. Dlya malykh razlichii mezhdu provodimostyami komponent podkhod teorii vozmushchenii soglasuetsya s chislennymi rezul’tatami.

Obrashchaya khaos vspyat’

5 December 2014 in 11:30

Борис Файн, Сколковский Институт Науки и Технологий

Понятие "хаос" часто упоминается в контексте основ статистической физики. В то же время, до сих пор не до конца ясно, что называть хаосом в многочастичных квантовых системах. Существует распространённое мнение, что поведение квантовых систем является классически хаотичным в макроскопическом пределе на физически наблюдаемых (т.е. не слишком длинных) временах. В этом докладе будет показано, что, даже в макроскопическом пределе и на физически наблюдаемых временах, типичные неинтегрируемые системы взаимодействущих квантовых спинов не обладают определяющим свойством классического хаоса, а именно, экспоненциальмой чувствительностью к малым возмущениям. Этот результат получен путём сравнения поведения систем классических и квантовых спинов в ответ на неполное обращение спиновой динамики во времени. Такое обращение во времени известно в статистической физике как "Лошмидтовское эхо" и реализуемо методами ядерного магнитного резонанса как "магическое эхо". В последнем случае, отсутствие экспоненциальной чувствительности к малым возмущениям должно быть экспериментально наблюдаемо. [B. V. Fine, T. A. Elsayed, C. M. Kropf, and A. S. de Wijn, Phys. Rev. E 89, 012923 (2014)]

Admittance of a long diffusive SNS junction

28 November 2014 in 12:00

K.S. Tikhonov, M.V. Feigel’man

Issledovany dinamicheskie svoistva SNS perekhoda s zadannoi raznost’yu faz sverkhprovodnikov na dvukh beregakh pod deistviem slabogo vysokochastotnogo vneshnego napryazheniya. Ispol’zovan glavnym obrazom analiticheskii metod, osnovannyi na reshenii nestatsionarnogo uravneniya Uzadelya, okonchatel’nye vychisleniya provedeny chislenno. Vychislena veshchestvennaya i mnimaya chasti lineinoi vysokochastotnoi provodimosti Y(ω) kak funktsii staticheskoi raznosti faz φ pri proizvol’nom sootnoshenii mezhdu chastotoi ω, temperaturoi T, energiei Taulesa ETh, no predpolagaya, chto vse eti velichiny maly po sravneniyu so shchel’yu Δ v spektre sverkhprovodnika. Poluchennye rezul’taty nakhodyatsya v khoroshem soglasii s eksperimentom.
[Napravleno v Phys. Rev. B., oktyabr’ (2014)]

Usrednenie lokal’nykh skobok Puassona pri nalichii psevdofaz

21 November 2014 in 11:45

A.Ya. Mal’tsev

Density of states in a two-dimensional chiral metal with vacancies

14 November 2014 in 11:30

P. M. Ostrovsky

We study quantum interference effects in a two-dimensional chiral metal (bipartite lattice) with vacancies. We demonstrate that randomly distributed vacancies constitute a peculiar type of chiral disorder leading to strong modifications of critical properties at zero energy as compared to conventional chiral metals. In particular, the average density of states diverges as ρ ~ E-1 |lnE|-3/2 and the correlation length Lc ~ |lnE| in the limit E→0. When the average density of vacancies is different in the two sublattices, a finite concentration of zero modes emerges and a gap in the quasiclassical density of states opens around zero energy. Interference effects smear this gap resulting in exponentially small tails at low energies.

N=2 superkonformnye koset-modeli i Puasson-odnorodnye prostranstva

7 November 2014 in 11:30

Sergei Parkhomenko

N=2 spersimmetrichnye koset-modeli konformnoi teorii polya, naidennye v rabotakh Kazama i Suzuki, igrayut vazhnuyu rol’ v konstruktsii realistichnykh modelei teorii superstrun v 4-kh izmereniyakh. My formuliruem konstruktsiyu Kazama i Suzuki na yazyke troek Manina i ustanavlivaem sootvetstvie etikh modelei s gruppami Puassona-Li i Puasson-odnorodnymi prostranstvami.

Struktura i elektronnyi spektr allotropov fosfora

31 October 2014 in 11:30

L.A. Fal’kovskii

The small difference between the rhombohedral phosphorus lattice ($A$-7 phase) and the simple cubic phase as well as between phosphorene and the cubic structure is used in order to construct their quasiparticle band dispersion. We exploit the Peierls idea of the Brillouin zone doubling/folding, which has been previously employed in consideration of semimetals of the $V$ period and $IV$--$VI$ semiconductors. In the common framework, individual properties of phosphorus allotropes are revealed.

Strogo polozhitel’nye matritsy i vyrozhdennye M-krivye

31 October 2014 in 11:30

S. Abenda, P.G. Grinevich

My ustanavlivaet svyaz’ mezhdu dvumya konstruktsiyami v teorii reshenii uravneniya Kadomtseva-Petviashvili 2 - postroeniem tochnykh reshenii v terminakh preobrazovanii Darbu i predelami regulyarnykh konechnozonnykh reshenii, otvechayushchikh tak nazyvaemym M-krivym.

Rezonansy i sokhranyayushchiesya toki v modeli sh-Gordon v formfaktornom podkhode

24 October 2014 in 11:30

M.Yu. Lashkevich, Ya.P. Pugai

V modeli sh-Gordon i v brizernom sektore modeli sin-Gordon v ramkakh formfaktornogo podkhoda naideny tozhdestva mezhdu operatorami, otvechayushchie rezonansnym tozhdestvam v teorii vozmushchenii. Izucheny reduktsii modeli pri spetsial’nykh znacheniyakh bezrazmernogo parametra b k "lentochnym" minimal’nym konformnym modelyam, vozmushchennym relevantnym operatorom. Postroeny operatory, sovmestnye s reduktsiei. Pokazano, chto obshchii vid etikh operatorov ne zavisit ot znacheniya parametra b. V kachestve primera naideny vse formfaktory sovmestnykh s reduktsiei sokhranyayushchikhsya tokov i ikh proizvedenii v odnoi tochke.

Torzhestvennoe zasedanie, posvyashchennoe 50-letiyu ITF im. L.D. Landau RAN

17 October 2014 in 11:30

Прграмма будет объявлена дополнительно

Ambegaokar-Eckern-Schön theory for a collective spin: geometric Langevin noise

10 October 2014 in 11:30

Alexander Shnirman (KIT), Yuval Gefen, Arijit Saha, Igor S. Burmistrov, Mikhail N. Kiselev, Alexander Altland

We consider small ferromagnetic particles or quantum dots close to Stoner instability, and investigate the dynamics of the total magnetization in the presence of tunneling coupling to the metallic leads. We generalize the Ambegaokar-Eckern-Sch\"on effective action and the corresponding semiclassical equations of motion from the U(1) case of the charge degree of freedom to the SU(2) case of the magnetization. The Langevin forces (torques) in these equations are strongly influenced by the geometric phase. As a first but nontrivial application we predict low temperature quantum diffusion of the magnetization on the Bloch sphere, which is governed by the geometric phase. We propose a protocol for experimental observation of this phenomenon.

Minimalnaya teoriya strun i ee skrytye algebraicheskie struktury

3 October 2014 in 11:30

Alexander Belavin

The aim of this talk is to report about of the computation of the correlation numbers in (p,q) Minimal Liouville gravity (MLG). In this work we conjecture that the Douglas equation is applicable to the Minimal Liouville gravity as well as to Matrix Models of 2D gravity. This conjecture requires the following two questions to be answered: how to choose the desired solution of the Douglas string equation and an appropriate form of the so called resonance transformation from the KdV times to the Liouville coupling constants to satisfy the needed constraints which have to be fulfilled in MLG. In our study, using the connection of the approach to MLG based on the connection of the String equation with the Frobenius manifold structure, we find the necessary solution of the String equation. We also show that this solution together with the suitable choosen resonance transformation lead to the results which are consistent with the main requirements of (p,q) models of MLG (the so called selection rules). It is remarkable that the needed solution of the Douglas equation has a very simple form in the at coordinates on the Frobenious manifold in the general case of (p,q) Minimal Liouville.

Quantum quenches in the many-body localized phase

26 September 2014 in 11:30

Maksym Serbyn, Z. Papic, Dmitry Abanin

Many-body localized (MBL) systems are characterized by the absence of transport and thermalization, and therefore cannot be described by conventional statistical mechanics. In this talk I will discuss the behaviour of local observables in an isolated MBL system following a quantum quench. For the case of a global quench, the local observables reach stationary, highly non-thermal values at long times as a result of slow dephasing characteristic of the MBL phase. These stationary values retain the local memory of the initial state due to the existence of local integrals of motion in the MBL phase. The temporal fluctuations around stationary values exhibit universal power-law decay in time, with an exponent set by the localization length and the diagonal entropy of the initial state. Such a power-law decay holds for any local observable and is related to the logarithmic in time growth of entanglement in the MBL phase. This behaviour distinguishes the MBL phase from both the Anderson insulator (where no stationary state is reached), and from the ergodic phase (where relaxation is expected to be exponential). Quench protocols considered in this talk can be naturally implemented in systems of ultra cold atoms in disordered optical lattices, and the behaviour of local observables provides a direct experimental signature of many-body localization. [arXiv:1408.4105; arXiv:1403.0693]

V svyazi s bolezn’yu dokladchika doklad otmenyaetsya

19 September 2014 in 11:30

S.V. Iordanskii

Osnovnoe sostoyanie dvusloinoi geterostruktury v bol’shikh magnitnykh polyakh

Kontsentratsiya svetovogo izlucheniya na nano-masshtabe s pomoshch’yu ustroistva, vypolnennogo iz opticheski prozrachnogo dielektrika

12 September 2014 in 11:30

Vergeles S.S., Sarychev A.K. (ITPE RAN), Bogdanov A (WD company, USA)

V nastoyashchee vremya dlya prakticheskikh primenenii vazhnoi zadachei yavlyaetsya kontsentratsiya svetovogo izlucheniya na masshtabakh, znachitel’no men’shikh difraktsionnogo predela. Odnim iz reshenii yavlyaetsya ispol’zovanie metallicheskikh chastits malogo razmera, na kotorykh proiskhodit vozbuzhdenie poverkhnostnykh plazmonov. Dlina volny poverkhnostnogo plazmona mozhet byt’ znachitel’no men’she dliny volny sveta na etoi chastote, chto i pozvolyaet proizvodit’ trebuemuyu kontsentratsiyu izlucheniya. Nedostatkom takogo resheniya yavlyayutsya bol’shie omicheskie poteri v metallicheskikh chastitsakh, i, kak sledstvie, sil’nyi ikh nagrev, kotoryi privodit k degradatsii chastits. Eta problema mogla by byt’ reshena zamenoi metalla na prozrachnyi dielektrik. Tem ne menee, reshenie, osnovannoe na volnovode, polnost’yu vypolnennom iz dielektrika, obychno okazyvaetsya menee produktivnym, poskol’ku ne udayotsya dostignut’ toi zhe stepeni lokalizatsii svetovoi volny. Prichina sostoit v tom, chto dlya dielektricheskikh chastits malogo razmera vypolnennykh iz materiala s koeffitsientom prelomleniya poryadka edinitsy otsutstvuet analog poverkhnostnykh plazmonnykh kolebanii.
My predlagaem konstruktsiyu dielektricheskogo volnovoda so spetsial’nym nakonechnikom, kotoryi pozvolyaet kontsentrirovat’ svetovuyu volnu na masshtabe, sushchestvenno men’shem dliny volny. Rassmatrivaetsya zadacha, kogda kontsentratsiyu polya volny sleduet osushchestvit’ na poverkhnosti nekotoroi podlozhki v zaranee opredelyonnom meste (t.e. sozdat’ tak nazyvaemyi hotspot). Konstruktsiya volnovoda sostoit iz samogo dielektricheskogo volnovoda, vypolnennogo iz opticheski plotnogo dielektricheskogo materiala, kotoryi podkhodit pod nebol’shim uglom k poverkhnosti podlozhki i vypolnyaet funktsiyu podvoda izlucheniya. V volnovode dolzhna byt’ vozbuzhdena volna, imeyushchaya polyarizatsiyu magnitnogo polya vdol’ ploskosti podlozhki. Na kontse volnovoda dolzhen byt’ vypolnen tonkii nakonechnik, napravlennyi ortogonal’no poverkhnosti podlozhki. V rezul’tate na kontse nakonechnika voznikaet pik napryazhyonnosti elektricheskogo polya. My stroim kachestvennuyu i chastichno kolichestvennuyu kartinu raboty takogo roda volnovodov i predstavlyaem rezul’taty chislennogo modelirovaniya.

Formirovanie nanorazmernykh struek i kapel’ ul’trakorotkim lazernym impul’som pri fokusirovke na difraktsionnom predele

12 September 2014 in 11:30

N.A. Inogamov, V.V. Zhakhovskii i V.A. Khokhlov

Postroena novaya model’ i provedeny raschety formirovaniya nanokapel’ pri vozdeistvii ul’trakorotkogo lazernogo impul’sa na tonkuyu (10-100 nm) plenku zolota, napylennogo na steklyannuyu podlozhku. Vozdeistvie lazera privodit k plavleniyu v oblasti pyatna nagreva i termomekhanicheskomu otskoku metallicheskoi plenki ot podlozhki. V silu neodnorodnogo nagreva fokal’nogo pyatna otsloivshayasya plenka prinimaet formu kupola. Vpervye s pomoshch’yu teoreticheskoi modeli udalos’ ob’yasnit’ formirovanie nanokapel’. Nami ustanovleno, chto, vo-pervykh, v sluchae plenki iz zolota imeet mesto sil’noe snizhenie skorosti otskoka plenki ot stekla poskol’ku akusticheskii impedans zolota namnogo bol’she, chem u stekla. Vo-vtorykh, nanokapli obrazuyutsya vsledstvie kapillyarnoi fokusirovki veshchestva, kotoraya zaklyuchaetsya v poyavlenii napravlennoi k osi simmetrii kupola komponenty tormozyashchei sily. Poverkhnostnoe natyazhenie stanovitsya dinamicheski sushchestvennym v silu ukazannogo sil’nogo snizheniya skorosti otskoka ot stekla i malosti diametra fokal’nogo pyatna $D\sim 1$ mkm, kotoroe opredelyaetsya difraktsionnym predelom opticheskogo izlucheniya.

Coulomb blockade for tunneling through a “long island”

5 September 2014 in 11:30

M.V. Feigelman and A.S. Ioselevich

We consider a Coulomb blockade effects for tunnelling through a piece of wire with large resistance $R\gg 1$. This system can not be treated as a zero-dimensional one, as the dynamics of internal inhomogeneous degrees of freedom is crucial. At moderately high temperatures the linear conductance $G$ of the system is suppressed due to the one-dimensional Coulomb zero bias anomaly effect. At low $T$, besides the standard activational factor, there is an additional $T$-independent (though also exponentially strong!) suppression of $G$. It arises due to the tunnelling evolution of the charge in the wire to the equivipotential distribution. In the intermediate range of $T$ the $G(T)$ dependence is a power law, as in the phenomenological environmental theory. The effective ``environmental resistance'', entering the power exponent, is found explicitly. It depends on the length of the wire and on the positions of the contacts.


20 June 2014 in 11:30

Ivan Protopopov

We show that nonequilibrium phenomena in dispersive Luttinger liquids posses remarkable weak-strong coupling duality between bosonic and fermionic descriptions. The duality manifests itself both in the collisionless dynamics of a density pulse (via crossover from essentially free-fermion evolution to hydrodynamics) and in the relaxation of fermionic and bosonic excitations.

Dynamics of Complex Singularities in Water Waves.

20 June 2014 in 11:30

A.O. Korotkevich and P.M. Lushnikov

Stokes wave is the fully nonlinear gravity wave propagating with the constant velocity. We consider Stokes wave in the conformal variables which maps the domain occupied by fluid into the lower complex half-plane. Then Stokes wave can be described through the position and the type of complex singularities in the upper complex half-plane. We identi ed that this singularity is the square-root branch point. We reformulated Stokes wave equation through the integral over jump at the branch cut which provides the efficient way for finding of the explicit form of Stokes wave.

Kvantovye fluktuatsii polei vblizi raznykh gorizontov

6 June 2014 in 11:30

Grigorii Tarnopol’skii

My izuchaem kvantovye fluktuatsii polei vblizi raznykh gorizontov, ispol’zuya analogiyu s elektro-magnitnym effektom Shvingera. My rabotaem v rezhime, kogda gorizont eshche ne sformirovan. V dannom rezhime mozhno ispol’zovat’ Feinmanovskuyu funktsiyu Grina dlya vychisleniya effektivnogo deistviya dlya gravitatsionnogo polya. V effektivnom deistvii my nakhodim singulyarnye chleny, signaliziruyushchie o nestabil’nosti vakuuma.
(rabota v progresse s Aleksandrom Polyakovym)

Vliyanie svoistv podlozhki na strukturu vikhrei v isparyayushcheisya zhidkoi kaple

6 June 2014 in 11:30

Lev Barash

Kolichestvo vikhrei v ispryayushcheisya lezhashchei kaple i ikh napravleniya sushchestvenno zavisyat ot teploprovodnosti i ot tolshchiny podlozhki, ot kontaktnogo ugla, a takzhe ot parametrov zhidkosti. Vypolnen detal’nyi chislennyi raschet dannogo effekta. Naideny raspredelenie temperatury, a takzhe vikhrevaya struktura potokov zhidkosti v kaple. Rassmotrena “fazovaya diagramma” na ploskosti kontaktnyi ugol – otnoshenie teploprovodnostei podlozhki i zhidkosti, soderzhashchaya informatsiyu o kolichestve, orientatsii i prostranstvennom polozhenii vikhrei.

Defazirovka elektronov v grafene za schyot vzaimodeistviya s izgibnymi fononami.

30 May 2014 in 11:30

Konstantin Tikhonov

My issleduem defazirovku elektronov v grafene za schet vzaimodeistviya s izgibnymi fononami. Okazyvaetsya, chto sootvetstvuyushchii vklad mozhet byt’ poryadka elektron-elektronnogo vklada dazhe pri nizkikh temperaturakh. Vychislenie provoditsya v shirokom diapazone temperatur, prodemonstrirovano, chto obsuzhdaemyi vklad menyaet temperaturnoe povedenie s T2 na T c rostom temperatury i rastet s elektronnoi plotnost’yu, v otlichie ot vklada elektron-elektronnykh vzaimodeistvii, chto delaet printsipial’no vozmozhnym ego obnaruzhenie v eksperimentakh po slaboi lokalizatsii v grafene.

Quantum theory of a spaser-based nanolaser

23 May 2014 in 11:30

Vladimir M. Parfenyev and Sergey S. Vergeles

We present a quantum theory of a spaser-based nanolaser, under the bad-cavity approximation. We find first- and second-order correlation functions g(1)(t) and g(2)(t) below and above the generation threshold, and obtain the average number of plasmons in the cavity. The latter is shown to be of the order of unity near the generation threshold, where the spectral line narrows considerably. In this case the coherence is preserved in a state of active atoms in contradiction to the good-cavity lasers, where the coherence is preserved in a state of photons. The damped oscillations in g(2)(t) above the generation threshold indicate the unusual character of amplitude fluctuations of polarization and population, which become interconnected in this case. Obtained results allow to understand the fundamental principles of operation of nanolasers.

Bilinear equations on Painleve τ functions from CFT

16 May 2014 in 11:30

M. Bershtein, A. Shchechkin

Ob umnozhenii nositelei v grafene

25 April 2014 in 11:30

Denis Basko (CNRS, Grenobl’)

Izuchaetsya relaksatsiya odnogo vozbuzhdyonnogo elektrona v zone provodimosti grafena pri nulevoi temperature i urovne Fermi v dirakovskoi tochke posredstvom ispuskaniya elektronno-dyrochnykh par za schyot kulonovskogo vzaimodeistviya. Vazhnuyu rol’ v etom protsesse igraet otklonenie spektra ot konicheskoi formy (trigonal’naya gofrirovka). V rezul’tate, relaksatsiya okazyvaetsya zapreshchyonnoi dlya nekotorykh napravlenii nachal’nogo impul’sa elektrona i razreshyonnoi dlya drugikh (dlya etogo sluchaya soschitano vremya relaksatsii).


18 April 2014 in 11:30

V.V. Lebedev

Comments on useless questions on Van-der-Waals friction

4 April 2014 in 11:30

E.I. Kats

Flat-band and room-temperature superconductivity

28 March 2014 in 11:30

G.E. Volovik

Otchet o XVIII Mezhdunarodnom simpoziume "Nanofizika i nanoelektronika", 10-14 marta 2014 g., Nizhnii Novgorod

21 March 2014 in 11:30

Ya.V. Fominov

Solar to electric conversion with liquid crystals.

14 March 2014 in 11:30

Efim Kats

Provodimost’ napolovinu zapolnennogo urovnya Landau

7 March 2014 in 11:30

S.V. Iordanskii

Ideal’naya gidrodinamika snaruzhi i vnutri chernoi dyry: gamil’tonovo opisanie v koordinatakh Penleve-Gullstranda

28 February 2014 in 11:30

V.P. Ruban

Pokazano, chto pri ispol’zovanii koordinat Penleve-Gullstranda (Painlev{\'e}-Gullstrand) v ikh dekartovom variante gamil’tonian relyativistskoi ideal’noi gidrodinamiki v okrestnosti nevrashchayushcheisya chernoi dyry otlichaetsya vsego odnim prostym slagaemym ot sootvetstvuyushchego gamil’toniana v ploskom prostranstve-vremeni. Pri etom edinym obrazom opisyvaetsya takzhe i vnutrennyaya oblast’ chernoi dyry, poskol’ku v koordinatakh Penleve-Gullstranda otsutstvuet singulyarnost’ na gorizonte sobytii. Predstavleno tochnoe reshenie, opisyvayushchee statsionarnuyu akkretsiyu predel’no zhestkoi materii ($\varepsilon\propto n^2$) na dvizhushchuyusya chernuyu dyru vplot’ do tsentral’noi singulyarnosti. V priblizhenii lokal’noi induktsii vyvedeno uravnenie dvizheniya tonkoi vikhrevoi niti na fone takogo akkretsionnogo potoka. V yavnom vide vychislen gamil’tonian dlya zhidkosti s ul’trarelyativistskim uravneniem sostoyaniya $\varepsilon\propto n^{4/3}$ i reshena zadacha o tsentral’no-simmetrichnom statsionarnom techenii takoi materii.


21 February 2014 in 11:30

Khokhlov V.A., Inogamov N.A., Anisimov S.I., Zhakhovsky V.V., Emirov Yu.N., Ashitkov S.I., Komarov P.S., Agranat M.B.

A thin surface layer with high temperature and pressure can be produced by almost isochoric heating with a short enough laser pulse. The stretched molten material is formed during melting and hydrodynamical expansion of this layer. Bubble nucleation and cavitation are initiated if a suciently high tensile stress is generated in the melt. Expansion of the bubble ensemble leads to formation of low-dense foam-like material at later times. However, remarkable elasticity of the foam is retained during long time, leading to slow down of expansion. Meanwhile, very high temperature gradient results in ultrafast cooling of the melt. For the laser intensity below the ablation threshold the foam expansion stops, then starts to shrink and nally freezes into complex solid nanostructures, which are observed experimentally. A comparison of experimental results and molecular dynamics simulation is presented.

Vibrational Modes in Free Standing Graphene Films

14 February 2014 in 11:30

E.I.Kats and V.V. Lebedev

(submitted to PRB, 2014)

Novel phases in topological superconducting quantum dots

7 February 2014 in 11:30

Karen Michaeli (Weizmann Inst)

Recent progress in realizing topological superconductors has paved the road to study new physical phenomena resulting from the non-abelian statistics of the Majorana modes they host. A particularly interesting situation arises when Majorana bound states in a closed topological superconducting dot are coupled to external normal leads. In this talk , we will show that interactions with the quantum dot drive the lead electrons into a non-Fermi liquid phase, which can be understood by mapping the problem to a variant of a Kondo system. Interestingly, the non-Fermi liquid states in these systems are more robust than in the conventional two channel Kondo problem. This is because realizations with different numbers of metallic leads are connected to each other by a line of fixed points. We will conclude with a discussion of the experimental consequences of our theory.

Static and dynamic properties of polarization domains in ferroelectric nanostructures

31 January 2014 in 11:30

Igor Lukyanchuk

Developing of novel technologies of functionalization of nano-size ferroelectric samples emerged the growing interest in exploration of such naturally-formed structures as polarization domains. I will present two recent results concerning the dynamic and static properties of domain self-organization.
The first part of my talk will concern the possible application of the domain structures in emerging technologies of Terahertz-detecting devices. We have studied the dynamical permittivity in ferroelectric nanometricaly-thin films with periodic domain structure, sandwiched between two paraelectric layers. The resulting frequency-dependent permittivity demonstrates collective resonance mode in sub-Terahertz frequency region and Debye-like relaxation behavior at low frequencies.
In the second part of my talk I will consider the study of domain-shape instabilities, recently observed in the ferroelectric polymer PVDF-TrFE films having the lower orthorhombic crystallographic symmetry and demonstrating the hexagonal domain faceting. This effect can arise from purely electrostatic depolarizing forces. We show that in contrast to magnetic bubble shape domains where such type of deformation instability has a predominantly elliptical character, the emergence of more symmetrical circular harmonics is favored in ferroelectrics with high dielectric constant.

Pressure-balanced stationary mirror structures in an anisotropic plasma

24 January 2014 in 11:30

E.A. Kuznetsov, T. Passot, V.P. Ruban, P.L. Sulem

Based on Grad-Shafranov-like equations, a gyrotropic plasma where the pressures in the static regime are only functions of the amplitude of the local magnetic field is shown to be amenable to a variational principle with a free energy density given by the parallel tension. This approach is used to demonstrate that small-amplitude static holes constructed slightly below the mirror instability threshold identify with lump solitons of KPII equation and turn out to be unstable. It is also shown that regularizing effects such as finite Larmor radius corrections cannot be ignored in the description of large-amplitude mirror structures.

Poisk EDM zaryazhennykh chastits v nakopitelyakh spin-rezonansnym metodom: bor’ba s fonovymi effektami

17 January 2014 in 11:30

N. Nikolaev, F. Rathmann (IKP FZJ, Juelich) & A. Saleev (Samara SU & IKP FZJ)

T-neinvariantnost’ odin iz trekh ingredientov bariogenezisa po Sakharovu, naryadu s nesokhraneniem barionnogo (i leptonnogo) zaryada i dolzhnoi stepeni neravnovesnosti rasshireniya Vselennoi v stadii T-neinvariantnykh perekhodov s generatsiei barionnogo zaryada. EDM chastits i legkikh yader vozmozhen tol’ko pri narushenii T- i R-invarinatnosti. Signal EDM --- pretsessiya spina v elektricheskom pole, chto dlya zaryazhennykh chastits mozhet byt’ realizovano tol’ko v nakopitel’nykh kol’tsakh, a signal EDM mozhet imet’ nablyudaemuyu velichinu tol’ko v usloviyakh spinovogo rezonansa. S tochki zreniya dinamiki spina, dayushchie signal EDM polya imeyut smysl neideal’nykh EM polei v nakopitele. Neideal’nost’ magnitnykh polei nakopitelya imitiruet signal EDM, i v obychnykh nakopitelyakh s magnitnoi dorozhkoi lozhnyi effekt na 6-7 poryadkov vyshe iskomogo effekta EDM. Predmet doklada: poisk sposobov vydelit’ signal EDM na etom fone. Segodnya v mire est’ tol’ko odin uskoritel’, na kotorom mozhno popytat’sya iskat’ EDM protona i deitrona --- COSY v Yulikhe, i provesti eksperimenty po dinamike spina, neobkhodimye do stroitel’stva spetsializirovannykh nakopitelei (Bukkheiven? Fermilab? Yulikh?). Budet dana svodka rekordnykh rezul’tatov po spinovoi dinamike, poluchennykh na COSY za poslednie poltora goda.

Kompaktnoe uravnenie dlya voln na vode: teoriya i eksperiment

20 December 2013 in 11:30

Dmitrii Kachulin (NGU)

V doklade rassmatrivaetsya kompaktnoe nelineinoe uravnenie Zakharova dlya gravitatsionnykh voln na glubokoi vode, rasprostranyayushchikhsya v odnom napravlenii. Issledovany nekotorye resheniya etogo uravneniya. Metodom Petviashvili naideny lokalizovannye nelineinye resheniya tipa brizerov. Analiticheski dokazana neintegriruemost’ uravneniya Zakharova. Polucheno kompaktnoe kanonicheskoe preobrazovanie k fizicheskim peremennym (forma poverkhnosti i potentsial skorosti). Uravnenie obobshcheno na sluchai dvumernykh poverkhnostnykh voln, slaboneodnorodnykh v poperechnom napravlenii. Razrabotan chislennyi algoritm ego resheniya. Algoritm effektivno rasparallelen s pomoshch’yu tekhnologii OpenMP i MPI. Provedeny chislennye raschety formirovaniya dvumernykh ekstremal’nykh voln.

Integriruemye struktury v 2d Konformnoi teorii polya i 4d Supersimmetrichnoi kalibrovochnoi teorii polya

20 December 2013 in 11:30

Tarnopol’skii Grigorii Mikhailovich

Doklad posvyashchen rabotam na osnovanii kotorykh napisana dissertatsiya. Pervaya polovina doklada budet posvyashchena kratkomu vvedeniyu v sootvetstvie mezhdu Konformnoi teoriei polya v 2 izmereniyakh i N=2 supersimmetrichnoi teoriei Yanga-Millsa v 4 izmereniyakh. Vo vtoroi polovine doklada budut sformulirovany osnovnye rezul’taty, vklyuchennye v dissertatsiyu.

Nelineinaya stadiya modulyatsionnoi neustoichivosti

13 December 2013 in 11:30

Andrei Gelash (NGU)

V ramkakh odnomernogo fokusiruyushchego nelineinogo uravneniya Shredingera (NUSh) my nakhodim polnyi klass tochnykh, t.n. superregulyarnykh reshenii, opisyvayushchikh nelineinuyu stadiyu modulyatsionnoi neustoichivosti lokalizovannogo vozmushcheniya kondensata (prosteishego resheniya NUSh v vide kvazimonokhromaticheskoi volny). Dlya etogo my stroim obshchee N-solitonnoe reshenie NUSh na fone kondensata s pomoshch’yu metoda odevaniya i opredelyaem, v kakikh sluchayakh stolknoveniya solitonov privodyat k ikh pochti polnoi annigilyatsii. Superregulyarnye resheniya obnaruzheny nami vpervye i predstavlyayut soboi N par t.n. kvazi-Akhmedievskikh solitonov, voznikayushchikh iz vozmushcheniya i zatem razbegayushchikhsya v protivopolozhnykh napravleniyakh. T.k. kolichestvo par mozhet byt’ lyubym, chislo parametrov neogranichenno i obshchee reshenie opisyvaet shirokii klass nachal’nykh uslovii. V rabote obsuzhdaetsya vozmozhnost’ eksperimental’nogo obnaruzheniya superregulyarnykh reshenii v gidrodinamike i optike. Takzhe privoditsya polnaya klassifikatsiya solitonnykh reshenii NUSh na fone kondensata i stroitsya obobshchenie na vektornoe NUSh (sistema Manakova).

Statistika spinovykh fluktuatsii v kvantovoi tochke s izingovskim obmenom

6 December 2013 in 11:30

Д.С. Любшин, А.У. Шарафутдинов, И.С. Бурмистров

Rassmatrivaetsya vliyanie fluktuatsii odnochastichnykh urovnei na stonerovskuyu neustoichivost’ v kvantovykh tochkakh s sil’nym spin-orbital’nym vzaimodeistviem v ramkakh modeli universal’nogo gamil’toniana s izingovskim obmenom; takaya zadacha svoditsya k issledovaniyu statistiki ekstremumov nekotorogo gaussovskogo protsessa. Pokazano, chto (nesmotrya na sluchainost’ odnochastichnykh urovnei) prodol’naya spinovaya vospriimchivost’ i vse eyo momenty raskhodyatsya odnovremenno v tochke stonerovskoi neustoichivosti, polozhenie kotoroi opredelyaetsya tol’ko srednim rasstoyaniem mezhdu urovnyami.

Termomekhanicheskie aspekty kiral’nosti v zhidkikh kristallakh

29 November 2013 in 11:30

E.I. Kats, P.V. Dolganov

Seeing quantum mechanics by the naked eye in solid state condensates

22 November 2013 in 11:30

Natalia Berloff, DAMTP, Cambridge and Skoltech

In my talk I will discuss the phenomena observed in, and properties of, microcavity exciton-polariton condensates. These are condensates of mixed light and matter, consisting of superpositions of photons in semiconductor microcavities and excitons in quantum wells. Because of the imperfect confinement of the photon component, exciton-polaritons have a finite lifetime, and have to be continuously re-populated. Therefore, exciton-polariton condensates lie somewhere between equilibrium Bose-Einstein condensates and lasers. I discuss the coherence properties of exciton-polariton condensates predicted theoretically and studied experimentally, and the wide variety of spatial structures including quantised vortices, trapped states, states of a quantum harmonic oscillator and other coherent structures.

Long-range quantum Ising spin glasses at T=0: gapless collective excitations and universality

15 November 2013 in 11:30

Alexei Andreanov (MPG)

We solve the Sherrington-Kirkpatrick spin-glass in a transverse field, concentrating on the regime deep in the quantum glass phase at zero temperature. We find that the quantum glass is gapless everywhere in the quantum glass phase, with an Ohmic spectral function of low energy collective excitations. The physical origin of the latter is explained using an effective potential approach. We obtain the pseudogap in the distribution of local fields and its quantum smearing at small values of transverse fields $\Gamma$. For $\Gamma\ll J$ we find the low frequency spectral function to be independent of $\Gamma$. Like the low-$T$ solution of the classical SK model, the quantum glass is also controlled by a self-similarity of the ultrametric structure of metastable states. The self-similarity is related to the fixed point found in the classical case. We reinterpret these results within the TAP approach.

Emissiya elektronov i okislenie metallov pri vozdeistvii ul’trakorotkikh lazernykh impul’sov

8 November 2013 in 11:30

Sergaeva O.N. (ITMO)

Napravlennyi polimer s kompleksnymi vesami uzlov na dereve Keli

1 November 2013 in 11:30

D.S. Lyubshin

Na primere voznikayushchei v prilozheniyakh zadachi (vychisleniya raznovremennogo korrelyatora lokal’nogo i polnogo spinov v XY-modeli v sluchainom poperechnom pole na dereve Keli) rassmatrivayutsya voprosy: 1) o velichine kompleksnoi svobodnoi energii polimera v obshchem sluchae korrelirovannykh modulya i fazy vesa; 2) o logarifmicheskikh po dline polimera popravkakh v svobodnoi energii v sluchae negaussova veshchestveshchennogo vesa.

1. Spektral’nyi analiz variatsii dlitel’nosti sutok. 2. Spektry ryadov klimaticheskikh dannykh

25 October 2013 in 11:30

A.V. Byalko

Spontaneous breaking of isotropy observed in the electronic transport of rare-earth tritellurides

18 October 2013 in 11:30

P.G. Grigor’ev

We show that the isotropic conductivity in the normal state of rare-earth tritelluride RTe₃ compounds is broken by the occurrence of the unidirectinal charge density wave (CDW) in the conducting (a,c) plane below the Peierls transition temperature. In contrast with quasi-one-dimensional systems, the resistivity anomaly associated with the CDW transition is strong in the direction perpendicular to the CDW wave vector Q (a-axis) and very weak in the CDW wave vector Q direction (c-axis). We explain this result by calculating the electrical conductivity for the electron dispersion with momentum-dependent CDW gap as determined by angle-resolved photoemission spectroscopy (ARPES).


18 October 2013 in 11:30

N.A. Inogamov

Integriruemye vektornye uravneniya

11 October 2013 in 11:30

V.V. Sokolov

Rassmatrivayutsya uravneniya s dvumya nezavisimymi peremennymi otnositel’no neizvestnogo vektora U proizvol’noi dliny s koeffitsientami, kotorye yavlyayutsya funktsiyami ot skalyarnykh proizvedenii vektora U i ego proizvodnykh. Obsuzhdayutsya neobkhodimye usloviya integriruemosti takikh uravnenii. Izuchayutsya lokal’nye gamil’tonovy struktury dlya vektornykh uravnenii. Formuliruyutsya starye i nedavnie klassifikatsionnye rezul’taty.

Vliyanie ferromagnitnogo perekhoda na sdvig i zatukhanie opticheskogo fonona v CoS2

4 October 2013 in 11:30

L.A. Fal’kovskii

The effects of phonon anharmonicity, phonon-magnon and electron-phonon interactions on the temperature dependence of Raman optical phonon modes are theoretically investigated. Besides of the Klemens result for the phonon width due to anharmonicity, the corresponding lineshift is derived. We argue that the phonon decay into two magnons has very low intensity in ferromagnets with low Curie temperatures. Therefore, the electron interband transitions accompanied with the ferromagnetic ordering are included in considerations to get a good quantitative agreement with experiments.

Struktury, opisyvaemye nelineinymi volnovymi uravneniyami s prostranstvennoi nelokal’nost’yu

27 September 2013 in 11:30

Alfimov Georgii Leonidovich (Natsional’nyi issledovatel’skii universitet MIET, Zelenograd, Moskva)

Nelineinye volnovye uravneniya voznikayut v mnogochislennykh zadachakh sovremennoi matematicheskoi fiziki. Nelineinye ob’ekty, kotorye opisyvayutsya etimi uravneniyami, v chastnosti, kinki (begushchie volny tipa domennykh stenok) i brizery (pul’siruyushchie vo vremeni i lokalizovannye v prostranstve obrazovaniya) stali estestvennymi elementami opisaniya mnogikh fizicheskikh yavlenii.
Vmeste s tem vo mnogikh sluchayakh utochnenie iskhodnoi fizicheskoi modeli privodit k nelokal’nym obobshcheniyam iskhodnykh uravnenii. Poyavlenie nelokal’nosti mozhet byt’ svyazano s uchetom slozhnogo zakona dispersii (naprimer, v nelokal’noi dzhozefsonovskoi elektrodinamike) ili dal’nodeistviya v toi ili inoi forme (naprimer, v reshetochnykh modelyakh tipa modeli Frenkelya-Kontorovoi). Vopros o tom, kak izmenyayutsya svoistva zadachi pri perekhode k nelokal’nomu opisaniyu zasluzhivaet otdel’nogo issledovanii.
V doklade rassmatrivayutsya nelokal’nye obobshcheniya nelineinogo uravneniya Kleina-Gordona, gde vtoraya prostranstvennaya proizvodnaya zamenena operatorom svertki. Pokazyvaetsya, chto perekhod k takoi nelokal’noi modeli mozhet privodit’ k yavleniyu kvantovaniya skorostei kinkov i obrazovaniyu mul’tikinkovykh struktur.  Dlya chastnykh sluchaev predstavleny tochnye analiticheskie resheniya. Privodyatsya rezul’taty chislennogo scheta, svidetel’stvuyushchie o tom, chto takie uravneniya opisyvayut i dolgozhivushchie periodicheskie pul’satsii tipa brizerov.

Local conservation laws, structure of states, and entanglement in the many-body localized phase

20 September 2013 in 11:30

Maksym Serbyn, Z. Papic, Dmitry A. Abanin

In the first part of the talk we address the dynamics in the specific model for the many-body localized (MBL) phase. Recent numerical work revealed a slow, logarithmic in time, growth of the entanglement entropy for initial product states of an XXZ spin chain in a strong random magnetic field. We show that this surprising phenomenon results from the dephasing due to exponentially small interaction-induced corrections to the eigenenergies of different states.
In the second part of the talk, we build generic framework which allows to understand the dynamics in the MBL phase. We construct a complete set of local integrals of motion that characterize MBL phase. Our approach relies on the assumption that local perturbations act locally on the eigenstates in the MBL phase, which is supported with numerical simulations of the random-field XXZ spin chain. We describe the structure of the eigenstates in the MBL phase and discuss the implications of local conservation laws for the non-equilibrium quantum dynamics in the MBL phase. In particular, the logarithmic entanglement growth is a universal phenomenon characteristic of the many-body localized phase in any number of spatial dimensions, and reveals a broad hierarchy of dephasing time scales present in such a phase.

Odetye sostoyaniya v potokovom kubite

13 September 2013 in 11:30

E.V. Il’ichev (IPHT Jena, Germany)

Approximate analytical descriptions of the stationary single-vortex Marangoni convection inside an evaporating sessile droplet of capillary size

6 September 2013 in 11:30

L.Yu. Barash

Three versions of an approximate analytical description of the stationary single vortex Marangoni convection in an axially symmetrical sessile drop of capillary size are studied for arbitrary contact angle and compared with the results of numerical simulations. The first approach is heuristic extension of the well-known lubrication approximation. Two other descriptions are developed and named n\tau- and rz-description. They are free from most of restrictive assumptions of the lubrication approach. For droplets with large contact angles they result in better accuracy compared to the heuristic extension of the lubrication approach, which still gives reasonable results within the accuracy 10-30 per cent. For droplets with small contact angles all three analytical descriptions well agree with the numerical data.

Mesoscopic fluctuations of the inelastic lifetime in a quantum dot

21 June 2013 in 11:30

V.A. Kozii, M.A. Skvortsov

Volny-ubiitsy na poverkhnosti tryokhmernoi zhidkosti

21 June 2013 in 11:30

D.I. Kachulin (NGU), A.I. D’yachenko, V.E. Zakharov

Intstanton blow up equations and CFT

14 June 2013 in 11:30

M. Bershtein, B. Feigin, A. Litvinov

Zashchita diplomnykh rabot

7 June 2013 in 11:30

Sergei Belan, Vladislav Kozii, Baurzhan Mukhametzhanov, Vladimir Parfen’ev

приглашаются все желающие

Operatory Shredingera na triangulirovannykh poverkhnostyakh, SL(2) svyaznosti i preobrazovanie zvezda-treugol’nik.

24 May 2013 in 11:30

P.G. Grinevich, S.P. Novikov

V rabote S.P. Novikova 1997 goda bylo pokazano, chto s algebraicheskoi tochki zreniya diskretizatsiya operatorov vtorogo poryadka na treugol’noi reshyotke znachitel’no bolee estestvenna. Teoriya takikh operatorov na poverkhnostyakh s cherno-beloi triangulyatsiei byla razvita S.P. Novkovym i I.A. Dynnikovym. Klyuchevuyu rol’ pri etom (obespechivaya, v chastnosti, svyaz’ s diskretnymi integriruemymi sistemami) igraet preobrazovanie Laplasa, analogichnoe preobrazovaniyu Darbu dlya odnomernykh operatorov.
V doklade budut predstavleny novye rezul’taty avtorov. Nami pokazano, chto vse SL(2) svyaznosti na ukazannykh poverkhnostyakh stroyatsya po samosopryazhennym operatoram, dlya kotorykh preobrazovanie Laplasa estestvenno opredeleno v oboikh napravleniyakh. Krome togo, nami pokazano, chto preobrazovanie Laplasa estestvenno interpretiruetsya kak izvestnoe v klassicheskoi elektrotekhnike s 1899 goda preobrazovanie zvezda-treugol’nik.

Korrelyatsionnye funktsii v Minimal’noi teorii strun

17 May 2013 in 11:30

A. Belavin, B. Dubrovin, B. Mukhametzhanov

My poluchaem tochnye vyrazheniya dlya korrelyatorov v Minimal’noi Liuvilevskoi (p,q)-gravitatsii, iskhodya iz gipotezy, chto Statsumma teorii opredelyaetsya Strunnym uravneniem Duglasa. Chtoby dostich’ etogo, my nakhodim rezonansnye sootnosheniya, svyazyvayushchie Liuvilevskie konstanty svyazi s tak nazyvaemymi KdV konstantami svyazi. Dlya opredeleniya yavnogo vida Statsummy cherez reshenie strunnogo uravneniya my ispol’zuem svyazannuyu s nim strukturu algebry Vittena-Dizhgrafa-Verlinde-Verlinde.

O zakone vozrastaniya entropii i prichine neobratimosti dinamiki kvantovykh sistem

17 May 2013 in 11:30

G.B. Lesovik

My pokazyvaem, chto narushenie simmetrii po vremeni v dinamike bol’shikh sistem voznikaet iz-za narusheniya simmetrii v zapolnenii gil’bertova prostranstva. Sostoyaniya $\phi $, dlya kotorykh entropiya rastet, estestvennym obrazom porozhdayutsya v prirode, ili mogut byt’ prigotovleny po zhelaniyu eksperimental’no, a sostoyaniya im kompleksno-sopryazhennye ($\phi^* $), dlya kotorykh entropiya ubyvaet, net (khotya formal’no v silu printsipa superpozitsii oni i mogut sushchestvovat’). My ukazyvaem na to, chto v obshchem sluchae obrashchenie neizvestnykh sostoyanii nevozmozhno iz-za togo, chto operator kompleksnogo sopryazheniya antilineen. Dlya izvestnogo sostoyaniya slozhnost’ obrashcheniya eksponentsial’na v tipichnom sluchae bol’shoi sistemy. My illyustriruem na prostykh modelyakh sdelannye utverzhdeniya.

Effekt Meisnera i prodol’naya neustoichivost’ LOFF v sloistykh strukturakh sverkhprovodnik/ferromagnetik

26 April 2013 in 11:30

S.V. Mironov (IFM RAN, Nizhnii Novgorod), A.S. Mel’nikov, A.I. Buzdin

V rabote pokazano, chto v tonkoplenochnykh mnogosloinykh strukturakh S/F, S/F/N i S/F/F’ realizuetsya neustoichivost’ Larkina-Ovchinnikova-Ful’de-Ferrella, chto privodit k formirovaniyu profilya parametra poryadka, modulirovannogo vdol’ sloev. Pereklyuchenie mezhdu odnorodnym v ploskosti sloev sostoyaniem i prodol’nym sostoyaniem Larkina-Ovchinnikova-Ful’de-Ferrella mozhet byt’ obnaruzheno po ischeznoveniyu effekta Meisnera i vozniknoveniyu ostsillyatsii kriticheskoi temperatury kak funktsii perpendikulyarnoi komponenty magnitnogo polya. V S/F/F’ sistemakh takie pereklyucheniya mogut osushchestvlyat’sya kontroliruemym obrazom posredstvom izmeneniya ugla mezhdu vektorami namagnichennosti v F i F’ sloyakh.

Fast Melting and Crystallization, Powerful Elastic Shocks, and Surface Nano-structuring Caused by Ultrashort Laser Pulses

12 April 2013 in 11:30

N. Inogamov, V. Zhakhovsky, Yu. Petrov, V. Khokhlov, S. Ashitkov, K. Kishchenko, K. Migdal, D. Ilnitsky, M. Agranat, S. Anisimov, V. Fortov

Ultrafast energy deposition in a thin surface layer of metal target irradiated by femtosecond laser pulse may lead to formation of high-pressure wave which eventually breaks to a shock wave during its propagation into the bulk of target. Due to very high-rate deformation the material response to such ultrashort shock loading can be elastic, even for shock pressures approaching to the ultimate strength of solids. Mechanism of laser-induced generation of such shock waves in metals is studied in this work by means of two-temperature hydrodynamics (2T-HD) and molecular dynamics (MD) simulation techniques. 2T-HD method includes an effect of electron pressure on material motion, and utilizes a model of solid based on quantum density functional theory. The complex processes leading to generation of a shock wave, including 2T electron-ion relaxation, propagation of supersonic electron thermal wave, overheating of the solid and ultrafast homogeneous isochoric melting, and pressure build-up in the heated layer are investigated. The elastic-plastic transformation and respective structures of elastic-plastic shock waves for different laser intensities are discussed. It is demonstrated that the pressure in an elastic precursor is independent on absorbed energy, but it is coupled with pressure at the melting front. It is shown that ultrafast deposition of laser energy ~100 mJ/cm2 results in formation of a nonequilibrium two-temperature state lasting several picoseconds. Due to supersonic propagation of heat into the depth of metal the surface layer of ~100 nm thick is heated, where material gains the internal energy of ~1 eV/atom and melts quickly. Expansion of the heated layer leads to strong tensile stress applying to liquid, which triggers nucleation of bubbles followed by foaming of the melt. As our simulations indicate, the foam-like material at target surface may inflate to a micrometer-sized layer without significant decay of the inter-bubble walls because of the high surface tension of liquid metal. Next, the foam begins to collapse, which produces the complex morphology with configurations like bubbles, jets, mushrooms and other liquid nano-structures. In the meantime the surface temperature drops below the melting point and fast recrystallization initiates freezing of the surface nano-structures. Such nano-structures, including frozen bubbles beneath the recrystallized metal surface, were found in our experiments and simulations.

Spazer v nadporogovom rezhime: sdvig chastoty generatsii

5 April 2013 in 11:30

V.M. Parfen’ev, S.S. Vergeles

V rabote predstavleno teoreticheskoe opisanie mekhanizmov i printsipov raboty spazera. My ustanovili, chto chastota generatsii ustroistva umen’shaetsya pri uvelichenii moshchnosti nakachki. Svidetel’stva etomu yavleniyu soderzhatsya v rezul’tatakh eksperimental’nykh rabot po dannoi tematike. My pokazali, chto mekhanizm, vedushchii k umen’sheniyu chastoty generatsii, osnovan na prostranstvennoi deformatsii struktury laziruyushchei mody, kotoraya vyzyvaetsya neodnorodnym nasyshcheniem aktivnoi sredy. Nami byla razrabotana analiticheskaya skhema, pozvolyayushchaya uchityvat’ etu deformatsiyu v strukture mody. Rezul’taty chislennogo modelirovaniya kasatel’no velichiny sdviga chastoty generatsii nakhodyatsya v sootvetstvii s eksperimental’nymi dannymi.

Uprugo-plasticheskie yavleniya v udarnykh volnakh, vyzvannykh korotkimi lazernymi impul’sami

29 March 2013 in 11:30

V.A. Khokhlov, N.A. Inogamov, V.V. Zhakhovskii, S.I. Anisimov

Printsipial’nym otlichiem tverdogo veshchestva ot drugikh faz yavlyaetsya vozniknovenie uprugikh sdvigovykh napryazhenii pri izmenenii formy, v tom chisle pri odnoosnom szhatii. My dobavili uchet sdvigovykh napryazhenii v nashu skhemu dvukhtemperaturnykh termo-gidrodinamicheskikh raschetov. Rezul’taty sravnivayutsya s analogichnym raschetom bez ucheta sdvigovykh napryazhenii i s eksperimental’nymi dannymi. Pokazana printsipial’naya vazhnost’ ucheta sdvigovykh napryazhenii.

Elektron-elektronnye vzaimodeistviya i dispersiya plazmonov v grafene

15 March 2013 in 11:30

L.S. Levitov, A.V. Shtyk, M.V. Feigel’man

Plazmony v dvumernykh sistemakh s neparabolicheskim (Galileevski neinvariantnym) spektrom, kak naprimer v grafene, sil’no zavisyat ot elektron-elektronnogo vzaimodeistviya. S pomoshch’yu mnogochastichnogo opisaniya my pokazyvaem, chto dispersiya dlinnovolnovykh plazmonov svyazana s Fermi-zhidkostnymi konstantami vzaimodeistviya i skorost’yu kvazichastits. Eto obshchee sootnoshenie proillyustrirovano na primere modeli s N sortami fermionov, gde v vedushchem poryadke po bol’shomu N voznikaet stepennaya zavisimost’ chastoty plazmona ot elektronnoi kontsentratsii. Tochno takaya zhe perenormirovka predskazana dlya magnitoplazmona. Nakonets, my predlagaem ispol’zovat’ zavisimost’ dispersii plazmonov ot polozheniya zatvora dlya neposredstvennogo issledovaniya elektron-elektronnykh vzaimodeistvii.

Integriruemye neodnorodnye 1+1 mernye sistemy gidrodinamicheskogo tipa

1 March 2013 in 11:30

V.V. Sokolov

Rassmatrivayutsya sistemy vida ut=A(u) ux+B(u), gde u - eto n-mernyi vektor, A(u)-matritsa, B(u)-nenulevoi vektor. V odnorodnom sluchae B=0 v kachestve kriteriya integriruemosti vybirayut sushchestvovanie lokal’nykh simmetrii ili zakonov sokhraneniya. V neodnorodnom sluchae k takoi tochke zreniya imeyutsya soderzhatel’nye kontrprimery. V rabote predlagaetsya opredelenie integriruemosti, svyazannoe s sushchestvovaniem u sistemy predstavleniya Laksa spetsial’nogo vida, nakhodyatsya vse integriruemye sistemy pri n=2 i stroyatsya klassy primerov dlya proizvol’nogo n.

Jet quenching in AA-collisions from RHIC to LHC

22 February 2013 in 11:30

B.G. Zakharov

I review my recent results on the nuclear suppression of the hadron spectra in AA-collisions (so called jet quenching) due to final state interaction in the hot QCD matter at RHIC and LHC energies.

Pogloshchenie ul’trazvuka i elektron-fononnyi teploobmen v gryaznykh provodnikakh za schet mekhanizma Mandel’shtama-Leontovicha

22 February 2013 in 11:30

Shtyk A.V., Feigel’man M.V., Kravtsov V.E.

Polucheno obshchee sootnoshenie mezhdu pogloshcheniem ul’trazvuka i elektron-fononnym potokom tepla, spravedlivoe dlya peregretogo elektronnogo gaza. Pokazano sushchestvovanie ryada mekhanizmov, vedushchikh k usileniyu etikh fizicheskikh protsessov v gryaznykh provodnikakh pri nizkikh chastotakh/temperaturakh , prichem vse oni tesno svyazany s mekhanizmom pogloshcheniya Mandel’shtama-Leontovicha. Naideno, chto pogloshchenie ul’trazvuka chuvstvitel’no k magnitnomu polyu i mozhet byt’ usileno na dva-tri poryadka pri magnitnykh polyakh ~ 10 T; znachitel’noe usilenie mozhet imet’ mesto takzhe v poluprovodnikovykh geterostrukturakh pri nalichii dopolnitel’noi ekranirovki Kulonovskogo vzaimodeistviya, naprimer zatvorom.

15 February 2013 in 11:30

V svyazi s prazdnovaniem 15.02.2013 goda 50-letiya IFTT zasedanie Uchenogo soveta i seminar otmenyayutsya.

Rumors from Workshop on Topology and Membranes in Cambridge

8 February 2013 in 11:30

E.I. Kats

Kratkoe soobshchenie o rabochem soveshchanii, prokhodivshem v Kembridzhe v noyabre 2012 goda

Kalibrovochnaya supersimmetrichnaya model’ Izinga na kubicheskoi reshetke vblizi kriticheskoi tochki v predstavlenii svobodnykh polei.

1 February 2013 in 11:30

S.N. Vergeles

Putem izucheniya korrelyatorov stepenei svobody kalibrovochnoi “supersimmetrichnoi” modeli Izinga na kubicheskoi reshetke ustanovlena priroda sovokupnosti tekh svobodnykh polei, kotorye predstavlyayut sistemu v kriticheskoi tochke. Eta zhe sovokupnost’ svobodnykh polei predstavlyaet kontinual’nuyu supersimmetrichnuyu abelevu kalibrovochnuyu teoriyu. Takim obrazom, opravdano nazvanie reshetochnoi sistemy. Provedeno sravnenie s 2D-model’yu Izinga. [Pis’ma v ZhETF, 96 (2), 128-134 (2012)]

Fermionnye ekraniruyushchie toki i U(1)-rassloeniya v otkrytoi strune.

25 January 2013 in 11:30

S.E. Parkhomenko

Metod Uizema i skobka Dubrovina Novikova v odnofaznom i mnogofaznom sluchayakh

18 January 2013 in 11:30

A.Ya. Mal’tsev

Podrobno rassmotrena protsedura usredneniya lokal’nykh teoretiko-polevykh skobok Puassona, predlozhennaya B.A. Dubrovinym i S.P. Novikovym dlya metoda Uizema, v sluchae vozniknoveniya rezonansov v mnogofaznoi situatsii. Glavnym rezul’tatom raboty yavlyaetsya nechuvstvitel’nost’ protsedury usredneniya po otnosheniyu k poyavleniyu rezonansnykh mnozhestv v prostranstve parametrov reshenii. Napominaem, chto zasedanie Uchenogo soveta proidet v Bol’shoi gostinoi Doma uchenykh NTsCh RAN !

Ekstremumy lunnoi orbity v chetvertichnom periode

11 January 2013 in 11:30

Byalko A.V.

VNIMANIE: V svyazi s remontom konferents-zala IFTT zasedanie Uchenogo soveta proidet v Bol’shoi gostinoi Doma uchenykh NTsCh RAN !

Teoriya gazoobmena atmosfera–okean i kontsentratsii izotopov ugleroda

11 January 2013 in 11:30

Byalko A.V.

VNIMANIE: V svyazi s remontom konferents-zala IFTT zasedanie Uchenogo soveta proidet v Bol’shoi gostinoi Doma uchenykh NTsCh RAN !

Продольное межслоевое магнитосопротивление в сильно анизотропных металлах

21 December 2012 in 11:30

P.G. Grigor’ev

Izuchaetsya prodol’noe magnitosoprotivlenie sil’no anizotropnykh kvazidvumernykh metallov v sil’nom magnitnom pole Bz, perpendikulyarnom provodyashchim sloyam. Neobkhodimost’ postroeniya teorii magnitosoprotivleniya v sil’no anizotropnykh kvazidvumernykh metallakh, vykhodyashchei za ramki tau-priblizheniya, byla vpervye pokazana v rabotakh [1-3], gde byli polucheny novye kachestvennye effekty, takie kak medlennye ostsillyatsii magnitosoprotivleniya i sdvig fazy bienii kvantovykh ostsillyatsii. Nedavno, v rabotakh [4,5] vpervye bylo pokazano, chto v kvazidvumernykh metallakh krome kvantovykh ostsillyatsii magnitnoe pole daet monotonnyi rost magnitosoprotivleniya, ne opisyvaemyi standartnoi teoriei. V chastnosti bylo polucheno, chto v sil’nom magnitnom pole prodol’noe mezhsloevoe soprotivlenie Rzz proportsional’no kvadratnomu kornyu ot polya Bz. V etikh rabotakh mezhsloevaya provodimost’ rasschityvalas’ kak tunnel’naya provodimost’ mezhdu dvumya provodyashchimi sloyami v predele malogo integrala pereskoka tz, men’shego kak rasstoyaniya mezhdu urovnyami Landau ωc tak i ikh shiriny Γ. Dannyi podkhod pozvolil analiticheski razreshit’ uravneniya na elektronnuyu funktsiyu v samosoglasovannom priblizhenii i vpervye poluchit’ novye kachestvennye svoistva magnitosoprotivleniya v sloistykh metallakh, kotorye v dal’neishem byli podrobno sravneny s eksperimentom [6]. Izuchenie opytnykh dannykh privelo nas k neobkhodimosti obobshcheniya etoi teorii na sluchai konechnogo tz dlya opisaniya bolee shirokogo klassa veshchestv. Krome etogo, dannyi podkhod vyzyval ryad voprosov o primenimosti formuly Kubo, kogda vremya sboya fazy elektronov bol’she vremeni mezhsloevogo tunnelirovaniya. V rabote [7] eti rezul’taty obobshchayutsya na sluchai konechnogo mezhsloevogo integrala pereskoka tz. Raschet provodimosti opiraetsya na trekhmernyi sil’no-anizotropnyi zakon dispersii elektronov, vykhodya za ramki dvukh provodyashchikh sloev. Eto snimaet voprosy o primenimosti formuly Kubo i pozvolyaet poluchit’ novye kachestvennye zavisimosti. V starom predele tz ≪ Γ, ωc vosproizvoditsya kornevaya zavisimost’ magnitosoprotivleniya, poluchennaya mnoi ranee v rabotakh [4,5]. Krome etogo, imeetsya shirokaya oblast’ lineinogo magnitosoprotivleniya v promezhutochnom pole pri 2tz < ωc < (2tz)2 / Γ, perekhodyashchaya v kornevuyu zavisimost’ pri dal’neishem uvelichenii polya. Takaya lineinaya zavisimost’ i krossover nablyudayutsya vo mnogikh sil’no-anizotropnykh provodnikakh, vklyuchaya organicheskie metally i vysokotemperaturnye sverkhprovodyashchie soedineniya: kupraty i pniktidy. Publikatsii: [1]. P.D. Grigoriev et al., Phys. Rev. B 65, 60403(R) (2002). [2]. M.V. Kartsovnik, P.D. Grigoriev, W. Biberacher, N.D. Kushch, P. Wyder, Phys. Rev. Lett. 89, 126802 (2002). [3]. P.D. Grigoriev, Phys. Rev. B 67, 144401 (2003); cond-mat/0204270. [4]. P.D. Grigoriev, Phys. Rev. B 83, 245129 (2011). [5]. P.D. Grigoriev, JETP Letters 94, 47 (2011). [6]. P.D. Grigoriev, M. V. Kartsovnik, W. Biberacher, Phys. Rev. B 86, 165125 (2012). [7]. P.D. Grigoriev, to be published.

Konechno-temperaturnye fazovye perekhody i uporyadochennye sostoyaniya v kvantovykh frustrirovannykh modelyakh Izinga

14 December 2012 in 11:30

S.E. Korshunov

Pokazano, chto v kvantovoi antiferromagnitnoi modeli Izinga na treugol’noi reshyotke temperatury fazovykh perekhodov, otdelyayushchikh kriticheskuyu fazu ot uporyadochennoi i razuporyadochennoi faz v slabykh polyakh lineino zavisyat ot velichiny polya. Eti zhe vyvody spravedlivy i v otnoshenii analogichnoi frustrirovannoi modeli na kvadratnoi reshyotke [PRB 85, 134526 (2012)]. Provedeno chislennoe issledovanie nul’temperaturnoi fazovoi diagrammy kvantovoi frustrirovannoi modeli Izinga na kvadratnoi reshyotke. Ustanovleno, chto v shirokom intervale magnitnykh polei v sisteme prisutstvuet dal’nii poryadok, struktura kotorogo v terminakh dimernogo predstavleniya sootvetstvuet polosatoi faze (columnar phase) [S. Wenzel, T. Coletta, S.E.K. and F. Mila, PRL 109, 187202 (2012)]

Quantum synchronization

7 December 2012 in 11:30

Юлий Назаров (TU Delft)

We show theoretically the possibility of quantum synchronization of Josephson and Bloch oscillations in a superconducting device. One needs an LC oscillator to achieve exponentially small rate of synchronization errors. The synchronization leads to quantization of transresistance similar to that in (Fractional) Quantum Hall Effect.

Formfaktory v modeli sh-Gordon, deformirovannaya algebra Virasoro i rezonansnye tozhdestva

23 November 2012 in 11:30

M. Lashkevich, Ya. Pugai

Izuchaetsya algebra vershinnykh operatorov, voznikayushchaya v predstavlenii svobodnymi polyami dlya formfaktorov lokal’nykh operatorov modeli sh-Gordon. Pokazano, chto eta algebra predstavlyaet soboi vyrozhdennyi sluchai proizvedeniya deformirovannoi algebry Virasoro i algebry Gaizenberga, otvechayushchei odnomu svobodnomu polyu. Eto pozvolyaet postroit’ spletayushchie operatory mezhdu predstavleniyami etoi algebry. S pomoshch’yu spletayushchikh operatorov my poluchaem yavno ryad tozhdestv mezhdu formfaktorami. Eti tozhdestva imeyut smysl rezonansnykh tozhdestv mezhdu operatorami teorii, a takzhe pozvolyayut naiti formfaktory sokhranyayushchikhsya tokov v teorii.

NSR conformal blocks with Ramond fields from AGT correspondence

16 November 2012 in 11:30

A. Belavin, B. Mukhametzhanov

We use AGT correspondence between N = 2 SUSY Yang-Mills theory on R4/Z2 and two-dimensional CFT model with the algebra H \plus sl(2)2 \plus NSR to obtain the explicit expressions for 4-point NSR conformal blocks including Ramond fields in terms of Nekrasov partition functions and correlation functions of sl(2)2 WZW model.

Simmetricheskie mnogochleny i teorema Liuvillya

2 November 2012 in 11:30

A.B. Shabat

Rassmatrivayutsya svoistva proizvodyashchei funktsii vektornykh polei, pervymi integralami kotorykh yavlyayutsya simmetricheskie mnogochleny. Ustanovlena svyaz’ poluchennykh uravnenii s teoriei mnogofaznykh reshenii nelineinykh uravnenii matematicheskoi fiziki

On the scaling of logarithmic correctrons

26 October 2012 in 11:30

L. Shchur, B. Berche (University Henri Poincare, France) and P. Butera (Univesity Milano-Bicocca, Italy)

We present a solution of the non linear renormalization group equations leading to the leading and subleading singular behaviours of physical quantities (free energy density, correlation length, internal energy, specific heat, magnetization, susceptibility and magetocaloric coefficient) at the critical temperature in a non vanishing magnetic field. The solutions i) lead to exact cancellation of logarithmic corrections in universal amplitude ratios and ii) prove recently proposed relations among logarithmic exponents.

Pogloshchenie ul’trazvuka i energeticheskaya relaksatsiya v gryaznykh provodnikakh pri nizkikh temperaturakh

19 October 2012 in 11:30

A.V. Shtyk, M. V. Feigel’man, V.E. Kravtsov

Khorosho izvestno, chto v gryaznykh provodnikakh pri nizkikh temperaturakh imeetsya destruktivnaya interferentsiya vzaimodeistviya fononov s elektronami za schet sdviga ionov i primesei sootvetstvenno. Iz-za etogo fonony okazyvayutsya ne v sostoyanii vozbudit’ diffuzionnye mody elektronov. My rassmatrivaem dva sluchaya, kogda delo obstoit inache: 1) nepolnaya Kulonovskaya ekranirovki i 2) nalichie neskol’kikh vetvei v spektre dispersii elektronov. V doklade budet rassmotrena energeticheskaya relaksatsiya i pogloshchenie ul’trazvuka. Takzhe my ukazhem na tesnuyu svyaz’ etikh dvukh yavlenii, sokhranyayushchuyusya dazhe dlya sil’no peregretykh sostoyanii elektronnogo gaza.

O neintegriruemosti 2-D gidrodinamiki zhidkosti so svobodnoi granitsei

12 October 2012 in 11:30

A.I. D’yachenko, D.I. Kachulin i V.E. Zakharov

Eksperimental’naya realizatsiya sverkhprovodyashchego tripletnogo spinovogo klapana

12 October 2012 in 11:30

Ya.V. Fominov

V rabote [Ya.V. Fominov et al., Pis’ma v ZhETF 91, 329 (2010)] byla predskazana vozmozhnost’ realizatsii sverkhprovodyashchego tripletnogo spinovogo klapana v sisteme SFF (gde S - sverkhprovodnik, F - ferromagnetik). Effekt spinovogo klapana (vozmozhnost’ vklyucheniya/vyklyucheniya sverkhprovodimosti slabym vneshnim magnitnym polem) osnovan na tom, chto kriticheskaya temperatura sistemy zavisit ot ugla mezhdu namagnichennostyami dvukh ferromagnetikov nemonotonnym obrazom, dostigaya minimuma pri nekotorom ugle mezhdu 0 i π. Svyazano eto s generatsiei v silu effekta blizosti dal’nodeistvuyushchei nechyotnoi po chastote tripletnoi komponenty. V doklade budet rasskazano ob eksperimental’nom podtverzhdenii predskazannogo effekta, opublikovannom v nedavnei stat’e P.V. Leksin, N.N. Garif'yanov, I.A. Garifullin, Ya.V. Fominov, J. Schumann, Y. Krupskaya, V. Kataev, O.G. Schmidt, B. Büchner, Phys. Rev. Lett. 109, 057005 (2012).

Kvantovyi elektronnyi transport v dvumernykh kontaktakh pri nenulevoi temperature

5 October 2012 in 11:30

T. V. Krishtop, K. E. Nagaev (Kotelnikov IRE)

Rassmatrivaetsya prokhozhdenie elektronov cherez dvumernyi ballisticheskii kontakt vblizi otsechki po toku. Rasseyanie elektronov na fridelevskikh ostsillyatsiyakh zaryadovoi plotnosti privodit k izlomu v koeffitsiente prokhozhdeniya na poverkhnosti Fermi, i, kak sledstvie, k lineinoi zavisimosti provodimosti ot temperatury. Znak lineinogo po temperature slagaemogo opredelyaetsya radiusom elektron-elektronnogo vzaimodeistviya.

Higgs bosons, t-quarks and Nambu sum rule

28 September 2012 in 11:30

G. Volovik and M. Zubkov

It may appear that the recently found resonance at MH1 = 125 GeV is not the only Higgs boson. We point out the possibility that the Higgs bosons are composite and that there exists, at least, one more composite Higgs excitation, whose mass MH2 ~ 325 GeV satisfies the Nambu sum rule MH12 + MH22 = 4 MT2, where MT ~ 174 GeV is the t-quark mass. CDF collaboration at Fermi Lab and CMS collaboration at LHC reported a small excess in this region.
In addition, there may appear two charged Higgs particles with masses around 245 GeV, which together also obey the Nambu rule. A certain excess of events in this region has been observed by ATLAS collaboration at LHC. Originally this sum rule was suggested by Nambu in 1985 for the Helium 3 superfluid.
(based on our paper arXiv:1209.0204)

Some preliminary results on Brownian motion in time dependent potential

21 September 2012 in 11:30

Efim Kats

Zaryazhennye makrochastitsy nad zhidkim geliem

21 September 2012 in 11:30

A.M. Dyugaev, P.D. Grigor’ev, E.V. Lebedeva

Analiz svoistv plazmy s makrochastitsami (pylevoi plazmy) pri kriogennykh temperaturakh privel nas k neobkhodimosti uchest’ effekty kondensatsii geliya na etikh chastitsakh. Mikronnye chastitsy v nasyshchennom pare geliya pokryty plenkoi zhidkogo geliya tolshchinoi okolo 100 A. Eto ogranichivaet ikh elektronnyi zaryad, tak kak plenka geliya slabopronitsaema dlya elektronov. Isklyucheniem yavlyayutsya klastery Cs, Rb, i K, kotorye ne smachivayutsya geliem.

Rayleigh-Taylor turbulent mixing

7 September 2012 in 11:30

Snezhana I. Abarzhi (The University of Chicago, Chicago, IL, USA)

We observe Rayleigh-Taylor (RT) turbulent mixing while looking at how water flows out from an overturned cup. This process governs a broad variety of natural phenomena from astrophysical to atomistic scales. It influences the formation of the ‘hot spot’ in inertial confinement fusion, drives penetration of stellar ejecta into pulsar wind nebula, dominates energy transport in core-collapse supernova, controls material transformation under high strain rates, and strongly affects the dynamics of shocks and blast waves, as wells as flows in atmosphere and ocean.
It was commonly accepted that Rayleigh-Taylor mixing is a process similar to turbulence in a single fluid or plasma. With this idea in mind, experiments designed experiments at high power laser systems Omega (LLE, Rochester, USA) and NIC (LLNL, Livermore, USA) to reproduce and study astrophysical phenomena, such as supernova explosion, in laboratory plasmas under extreme conditions of high energy density. A laser beam with the giant power of trillions of watts deposited energy onto a tiny target within tens of billionth of a second – the time sufficient for the light to pass only a few meters. The target materials turned into hot and dense plasmas and accelerated at the rate of ten billions of the Earth gravity. The expectation was for a ‘super-turbulence’ to develop yet the plasmas flow exhibited significant degree of order.
We developed and applied the new theoretical concept, the invariance of the rate of momentum loss, to describe the transports of mass, momentum and energy in RT turbulent mixing and to capture its anisotropic, inhomogeneous and statistically unsteady character. It was showed that invariant,scaling and spectral properties of unsteady turbulent mixing differ substantially from those of isotropic and homogeneous turbulence. Rayleigh-Taylor mixing indeed exhibits more order, stronger correlations, weaker fluctuations, and steeper statistical spectra when compared to canonical turbulence. While explaining the experimental observations, these theoretical results have also indicated new approaches for mitigation and control of turbulent mixing processes in inertial confinement fusion, for rational design of experiments for high energy density laboratory astrophysics, and for advancement of numerical simulations

Co-tunneling current through the two-level quantum dot coupled to magnetic leads: A role of exchange interaction

22 June 2012 in 11:30

A. Sharafutdinov

The cotunneling current through a two-level quantum dot weakly coupled to ferromagnetic leads is studied in the Coulomb blockade regime. The cotunneling current is calculated analytically under simple but realistic assumptions as follows: (i) the quantum dot is described by the universal Hamiltonian, (ii) it is doubly occupied, and (iii) it displays a fast spin relaxation. We find that the dependence of the differential conductance on the bias voltage is significantly affected by the exchange interaction on the quantum dot. In particular, for antiparallel magnetic configurations in the leads, the exchange interaction results in the appearance of interference-type contributions from the inelastic processes to the cotunneling current. Such dependence of the cotunneling current on the tunneling amplitude phases should also occur in multi-level quantum dots weakly coupled to ferromagnetic leads near the mesoscopic Stoner instabilities.

Beyond log-log scaling of critical collapse of Nonlinear Schrodinger equation

22 June 2012 in 11:30

Pavel Lushnikov

We study the collapse of the nonlinear Schrodinger equation (NLS) in critical case of dimension two. The collapse describes e.g. self-focusing of light in nonlinear Kerr media. The scaling of self-similar solutions near collapse point has (t0-t)1/2 scaling law with the logarithmic modifications of log-log type. We show that the leading order log-log modification occurs for nonrealistic exponentially large amplitudes of light. Instead we derived a new equation for adiabatically slow parameter which determines the system dynamics. Based on that equation we develop a perturbation theory for scaling modifications beyond leading log-log order and perform detailed comparison with simulations.

Issledovanie rasprostraneniya plazmonno-polyaritonnykh svyazannykh mod v gibridnom volnovode

15 June 2012 in 11:30

Vergeles S.S., Belan S.A., Vorob’yov P.E.

My rassmatrivaem gibridnyi volnovod, predstavlyayushchii iz sebya sterzhenb krugovogo secheniya, raspolozhennyi na blizkom rasstoyanii ot metallicheskogo ekrana. My issleduem svoistva rasprostraneniya svyazannykh plazmonno-polyaritonnykh mod vdol’ napravleniya dielektricheskogo sterzhnya. Tsel’ rassmatreniya podobnykh sistem -- dobit’sya odnovremenno sil’noi poperechnoi lokalizatsii svyazannoi mody (do razmerov znachitel’no men’shikh dliny volny v okruzhayushchei prostranstve) i bol’shoi dliny rasprostraneniya, to est’ malykh poter’. My rassmatrivaem dva predel’nykh sluchaya, sootvetstvuyushchikh dvum raznym diapazonam chastot i/ili drugomu naboru materialov. Pervyi variant sootvetstvuet tomu, chto chastota rasprostranyayushcheisya mody blizka k plazmennoi chastote metalla. V etom sluchae my pokazyvaem, chto sil’naya poperechnaya lokalizatsiya svyazannoi mody deistvitel’no dostizhima. Vtoroi sluchai, uee realizovannyi eksperimental’no, sootvetstvuet predelu pochti ideal’nogo metallicheskogo zerkala. My issleduem vopros o lokalizatsii i pokazyvaem, chto ona v etom predele znachitel’no slabee. Nakonets, v oboikh predelakh my otsenivaem dlinu rasprostraneniya mody.

Weakly coherent regime of interlayer magnetoresistance

8 June 2012 in 11:30

P.D. Grigor’ev

Abstract: Recently the theory of interlayer magnetoresistance in the strongly anisotropic metals has been proposed (by the author) in the regime, where the interlayer transfer integral of electrons is smaller than the cyclotron energy and Landau level broadening due to disorder [1-3]. It was shown [1,2] that in this “weakly coherent” regime the monotonic part of magnetoresistance has qualitatively different behavior than in the standard theory. The damping of magnetic quantum oscillations and the angular dependence of magnetoresistance were also predicted to strongly change in this regime from the coherent 3D case [1,3]. In the present paper [4] we determine the applicability region of the theory in Refs. [1-3] and perform the detailed comparison with experiment on the field dependence of interlayer magnetoresistance of the pressurized (to the normal state) layered organic metal a-(BEDT-TTF)2KHg(SCN)4. The high quasi-two-dimensional anisotropy, when the interlayer hopping time is shorter than the electron mean-free time and than the cyclotron period, leads to a dimensional crossover and to strong deviations from the conventional three-dimensional theory of magnetoresistance. The monotonic field dependence is found to change from the conventional behavior at low magnetic fields to an anomalous one at high fields. The shape of Landau levels, determined from the damping of magnetic quantum oscillations, changes from Lorentzian to Gaussian. This indicates the change of electron dynamics in the disorder potential from the usual coherent three-dimensional regime to a new regime, which can be referred to as weakly coherent. 1. P.D. Grigoriev, “Weakly incoherent regime of interlayer conductivity in magnetic field”, Phys. Rev. B 83, 245129 (2011). 2. P. D. Grigoriev, “Monotonic growth of interlayer magnetoresistance in strong magnetic field in very anisotropic layered metals”, JETP Lett. 94, 47 (2011). 3. P.D. Grigoriev, “New features of magnetoresistance in the strongly anisotropic layered metals”, Физика низких температур, 37(9-10), 930 (2011). 4. P. D. Grigoriev, M. V. Kartsovnik, W. Biberacher, «Weakly coherent regime of interlayer magnetoresistance in organic metal α-(BEDT-TTF) 2KHg(SCN)4», arXiv:1205.0041.

Fluctuation conductivity in disordered superconducting films

1 June 2012 in 11:30

Konstantin S. Tikhonov, Georg Schwiete, and Alexander M. Finkel'stein

We study the effect of superconducting fluctuations on the longitudinal and the transverse (Hall) conductivity in homogeneously disordered films. Our calculation is based on the Usadel equation in the real-time formulation. We adjust this approach to derive analytic expressions for the fluctuation corrections in the entire metallic part of the temperature-magnetic field phase diagram, including the effects of both classical and quantum fluctuations. This method allows us to obtain fluctuation corrections in a compact and effective way, establishing a direct connection between phenomenological and microscopic calculations.

Fluctuoscopy of Superconductors

25 May 2012 in 11:30

A.A. Varlamov (Viale del Politecnico), Andreas Glatz, V.M. Vinokur (MSD ANL)

We derive the exact expressions for the fluctuation conductivity in disordered two dimensional superconductors as a function of temperature and magnetic field in the whole phase diagram above the upper critical field line Hc2(T). Ten diagrams of the first order corrections are grouped in four contributions of the different physical nature. We discuss their hierarchy in different domains of the phase diagram and identify that one responsible for quantum phase transition close to Hc2(0). Focusing on the vicinity of the quantum phase transition near zero temperature we arrive to the conclusion that as the magnetic field approaches the critical field Hc2(0) from above, a peculiar dynamic state consisting of clusters of coherently rotating fluctuation Cooper-pairs forms. We estimate the characteristic size ξQF(H) and lifetime τQF(H) of such clusters and indicate in the corresponding domain of the phase diagram, where such phenomenon can be observed. The derived values ξQF(H) and τQF(H) allow us to reproduce qualitatively the available results for the quantum fluctuation contributions to the in-plane conductivity, magnetization, and the Nernst coefficient.

Form Factors in the Φ1,2 perturbed minimal models

18 May 2012 in 11:30

Oleg Alekseev

We consider particular modification of the free-field representation of the form factors in the Bullough-Dodd model. The two-particles minimal form factors are excluded from the construction. As a consequence, we obtain convenient representation for the multi-particle form factors, establish recurrence relations between them and study their properties. The proposed construction is used to obtain the free-field representation of the lightest particles form factors in the Φ1,2 perturbed minimal models.

Topologiya planarnoi fazy sverkhtekuchego geliya-3

11 May 2012 in 11:30

Yurii Makhlin

Na osnove izucheniya zonnoi struktury v ob’eme pri pomoshchi metodov gomotopicheskoi topologii daetsya topologicheskaya klassifikatsiya topologicheskikh dielektrikov s simmetriei planarnoi fazy sverkhtekuchego geliya-3.

Prostaya nereshennaya zadacha elektrodinamiki i eyo primenenie k myagkoi materii

4 May 2012 in 11:30

Efim Kats

Provodimost’ grafena i elektronno-dyrochnye pary

27 April 2012 in 11:30

N. Guk, S.V. Iordanskii

O tsiklotronnom rezonanse v grafite

27 April 2012 in 11:30

Denis Basko (CNRS, Grenobl’)

Izuchaetsya tsiklotronnyi rezonans v grafite v slabykh magnitnykh polyakh, perpendikulyarnykh grafennym sloyam. Po rezul’tatam poslednikh izmerenii, tsiklotronnyi spektr soderzhit bolee 20 garmonik. Razrabotana kvaziklassicheskaya teoriya tsiklotronnogo rezonansa v grafite. Pokazano, chto izmerennyi spektr sootvetstvuet klassicheskomu dvizheniyu vblizi separatrisy, chto svidetel’stvuet o blizosti sistemy k perekhodu Lifshitsa.

Sound modes in non-magnetic dielectrics in a magnetic field

20 April 2012 in 11:30

I.E. Dzyaloshinskii, E.I. Kats

We show how gyro-magnetic phenomena dramatically affect vibrations in non-magnetic solids.

O d-metallakh s vysokovozbuzhdennoi elektronnoi podsistemoi

13 April 2012 in 11:30

S.I. Anisimov, N.A. Inogamov, Yu.V. Petrov, V.A. Khokhlov

Lazery ispol’zuyutsya dlya obrabotki raznoobraznykh konstruktsionnykh materialov. Vazhnym yavlyaetsya semeistvo perekhodnykh metallov. V rabote analiziruetsya nikel’, kak kharakternyi predstavitel’ etogo semeistva. Provedennye eksperimenty svidetel’stvuyut ob udivitel’no vysokoi plotnosti energii v nagretom sloe nikelya na poroge ablyatsii. Eto yavlenie podtverzhdaetsya provedennymi gidrodinamicheskimi i molekulyarno-dinamicheskimi raschetami. Rabota osnovyvaetsya na kvantovo-mekhanicheskom podkhode k termodinamike i teploprovodnosti dvukhtemperaturnogo sostoyaniya, v kotorom velika raznitsa mezhdu elektronnoi Te i ionnoi Ti temperaturami: Te >> Ti. Razrabotano novoe teoreticheskoe opisanie teploprovodnosti. Ono, vo-pervykh, uchityvaet sovremennye dannye po provodimosti rasplava nikelya, i, vo-vtorykh, opiraetsya na vypolnennye v rabote raschety elektron-elektronnogo s-s i s-d rasseyaniya, v kotorom uchastvuyut elektrony iz s- i d-zon perekhodnogo metalla. Nashi vychisleniya zamenyayut primenyavshuyusya ranee grubuyu asimptotiku, soglasno kotoroi chastota elektron-elektronnykh stolknovenii proportsional’na kvadratu elektronnoi temperatury.

Koagulyatsiya primesei v sverkhtekuchem gelii s obrazovaniem nanoprovolok i nanonitei

30 March 2012 in 11:30

Gordon Evgenii Borisovich (IPKhF RAN)

Golomorfnye sobstvennye funktsii vektornykh polei, svyazannykh s bezdispersionnym uravnenie Kadomtseva-Petviashvili.

23 March 2012 in 11:30

P.G. Grinevich, P.M. Santini

Rabota posvyashchena obosnovaniyu podkhoda k issledovaniyu bezdispersionnykh sistem, predlozhennomu Manakovym i Santini. My pokazyvaem, chto dlya operatora, vkhodyashchego v paru Laksa bezdispersionnogo KP, sushchestvuyut sobstvennye funktsii, golomorfnye po spektral’nomu parametru vne okrestnosti veshchestvennoi pryamoi.

On the accuracy of the Wang-Landau method

23 March 2012 in 11:30

L.N. Shchur

Wang-Landau method developed for the numerical estimation of the density of states in the system with the discrete energy spectrum. Original algorithm are based on the criterium of the histogram flatness, which in fact are never fulfilled. We found that accuracy may be associated with the properties of the transition matrix. Nevertheless, problem of the convergence to the stationary distribution is still open.

Quantum electrodynamics with anisotropic scaling: Heisenberg-Euler action and Schwinger pair production in the bilayer graphene

16 March 2012 in 11:30

M. I. Katsnelson, G. E. Volovik

We discuss quantum electrodynamics emerging in the vacua with anisotropic scaling. Systems with anisotropic scaling were suggested by Horava in relation to the quantum theory of gravity. In such vacua the space and time are not equivalent, and moreover they obey different scaling laws, called the anisotropic scaling. Such anisotropic scaling takes place for fermions in bilayer graphene, where if one neglects the trigonal warping effects the massless Dirac fermions have quadratic dispersion. This results in the anisotropic quantum electrodynamics, in which electric and magnetic fields obey different scaling laws. Here we discuss the Heisenberg-Euler action and Schwinger pair production in such anisotropic QED (arXiv:1203.1578v2).

Commuting vector fields and integrable PDEs of hydrodynamic type in multidimensions (joint work with S. V. Manakov)

2 March 2012 in 11:30

P.M. Santini

After summarizing the main features of the direct and inverse spectral transforms for vector fields, used to solve nonlinear multidimensional PDEs arising as commutation condition for vector fields, we concentrate on the inverse problem, a vector nonlinear Riemann problem (NRP), and i) we present a method to identify a class of exactly solvable NRPs, corresponding to distinguished examples of implicit solutions of the nonlinear PDEs; ii) we construct the longtime behavior of the solutions of such PDEs, studying in detail the analytic aspects of wave breaking in multidimensions. The above theory applies, in particular, to the following celebrated nonlinear PDEs of Mathematical Physics: the dispersionless Kadomtsev-Petviashvili, the heavenly and the dispersionless 2D Toda equations.

The structure of the superelastic&plastic shock wave.

24 February 2012 in 11:30

V.A. Khokhlov, N.A. Inogamov, V.V. Zhakhovskii, S.I. Anisimov, Yu.V. Petrov

Pri moshchnom korotkoimpul’snom lazernom vozdeistvii v veshchestve voznikayut "sverkhuprugie" udarnye volny kotorye dvizhutsya s "uprugoi" skorost’yu, v to vremya kak davlenie za volnoi znachitel’no prevyshaet klassicheskii predel uprugosti Gyugonyu. Dvizhenie takoi volny i sleduyushchei za nei plasticheskoi udarnoi volny skorrelirovanno. V doklade predstavleno dvizhenie i razvitie takoi struktury sverkhuprugoi i plasticheskoi udarnykh voln i dopolnitel’nykh voln szhatiya mezhdu nimi. Rabota budet dolozhena na konferentsii "El’brus-2012" i opublikovana v sbornike konferentsii i v stat’yakh: Inogamov N.A, Khokhlov V.A., Petrov Yu.V., Anisimov S. I., Zhakhovsky V.V., Demaske B. J., Oleynik I. I., White C.T., Ashitkov S. I., Khishchenko K.V., Agranat M. B. and Fortov V.E. "Ultrashort elastic and plastic shock waves in aluminum." // AIP Conference Proceedings. 2012. V. 1426

Kollaps v gidrodinamike i kolmogorovskii spektr

17 February 2012 in 11:30

E.A. Kuznetsov

Poslednie chislennye eksperimenty v ramkakh uravneniya Eilera dlya dvukh stalkivayushchikhsya vikhrevykh dipolei Lemba (P. Orlandi, S. Pirozzoli and G. F. Carnevale, J. Fluid Mech. (2012), vol. 690, pp. 288-320) svidetel’stvuyut v pol’zu vozniknoveniya kollapsa - protsessa, pri kotorom zavikhrennost’ obrashchaetsya v beskonechnost’ za konechnoe vremya po zakonu (t0-t)-1, razmer oblasti kollapsa umen’shaetsya kak (t0-t)½, a parallel’naya zavikhrennosti komponenta skorosti rastet kak (t0-t). Pri etom oblast’ maksimal’noi zavikhrennosti predstavlyaet soboi strukturu tipa blina. V dannoi rabote pokazano, chto vse ukazannye avtomodel’nosti mogut byt’ polucheny iz analiza osobennosti pri oprokidyvanii vikhrevykh linii. V moment kollapsa dlya zavikhrennosti Ω voznikaet zavisimost’ kolmogorovskogo tipa: Ω ⁓ x-2/3, gde x sovpadaet s napravleniem oprokidyvaniya.

O dvumernom uravnenii Shredingera v magnitnom pole s dopolnitel’nym kvadratichnym integralom dvizheniya

10 February 2012 in 11:30

V. G. Marikhin

Rassmotrena zadacha o kommutiruyushchikh kvadratichnykh kvantovykh operatorakh s magnitnym polem. Pokazana, chto lyubaya takaya para mozhet byt’ privedena k kanonicheskoi forme, kotoraya pozvolyaet postroit’ pochti polnuyu klassifikatsiyu reshenii uravnenii, neobkhodimykh i dostatochnykh dlya togo, chtoby para operatorov kommutirovala. Perekhod k kanonicheskoi forme osushchestvlyaetsya zamenoi peremennykh, privodyashchikh k peremennym tipa Kovalevskoi, analogichnoi toi, kotoraya voznikaet v teorii integriruemykh volchkov. V kachestve primera my rassmotrim dannuyu protseduru dlya dvumernogo uravneniya Shredingera v magnitnom pole, obladayushchego dopolnitel’nym kvadratichnym integralom dvizheniya.

O nekotorykh resheniyakh dvumernykh uravnenii tipa Shredingera v magnitnom pole

10 February 2012 in 11:30

V. G. Marikhin

Dlya postroeniya novykh reshenii dvumernykh uravnenii tipa Shredingera v magnitnom pole ispol’zuetsya metod odevaniya lineinym differentsial’nym operatorom obshchego vida. V sluchae needinichnoi metriki prointegrirovan klass reshenii s razdelyayushchimisya peremennymi do odevaniya. Pokazano, v chast- nosti, chto otnoshenie koeffitsientov pered operatorami differentsirovaniya v sluchae edinichnoi metriki udovletvoryaet uravneniyu Khopfa. Ustanovlena svyaz’ mezhdu resheniyami dvumernogo uravneniya eikonala s edinichnoi pravoi chast’yu i resheniyami uravneniya Khopfa.

Statistical properties of passive scalar in a random flow with a strong shear component

10 February 2012 in 11:30

I.V. Kolololov, Nguen Than Trung

We study mixing of passive scalar by a chaotic velocity field with a relatively strong regular shear component. We show that the tail of partition distribution function (PDF) of coarse-grained passive scalar field differs qualitatively from the corresponding asymptotics in the case of isotropic flow statistics.

Comment on “Triggering Rogue Waves in Opposing Currents”

27 January 2012 in 11:30

V.P. Ruban

Obnaruzhena metodologicheskaya oshibka v uravnenii, kotoroe ispol’zovano avtorami raboty [M. Onorato, D. Proment, and A. Toffoli, Phys. Rev. Lett. {\bf 107}, 184502 (2011)] v kachestve bazisnoi modeli pri opisanii formirovaniya anomal’nykh voln na neodnorodnykh vstrechnykh techeniyakh. Vyvedeno korrektnoe uravnenie i provedeno kolichestvennoe sravnenie nekotorykh rezul’tatov, sootvetstvuyushchikh pravil’noi i nepravil’noi modelyam.

Lokalizovannye opticheskie mody v fotonnykh kristallakh

27 January 2012 in 11:30

V.A. Belyakov

Daetsya obzor publikatsii 2011 goda po rezul’tatam rabot, provodivshikhsya v ramkakh Rossiisko-Yaponskogo i Rossiisko-Ukrainskogo grantov RFFI. Tematika issledovanii otnositsya k probleme lokalizatsii sveta v fotonnykh kristallakh i svyazannykh s etim opticheskikh yavlenii, a takzhe k izucheniyu stsepleniya molekul zhidkogo kristalla s ogranichivayushchimi ego poverkhnostyami, tak nazyvaemogo, poverkhnostnogo stsepleniya. Razvita analiticheskaya teoriya opticheskikh lokalizovannykh (kraevykh (EM) i defektnykh (DM)) mod v spiral’nykh sredakh. Naideny dispersionnye uravneniya dlya EM i DM mod v khiral’nykh zhidkikh kristallakh (ZhK) i vyrazheniya, opisyvayushchie prostranstvennoe raspredeleniya plotnosti energii v lokalizovannykh modakh. Polucheny yavnye analiticheskie vyrazheniya dlya koeffitsientov otrazheniya i propuskaniya struktur, obladayushchikh lokalizovannymi modami. V predele tolstykh ZhK sloev naideny analiticheskie vyrazheniya dlya vremeni zhizni mod (mnimoi sostavlyayushchei ikh chastoty). Pokazano, chto vremya zhizni EM mod v etom predele vozrastaet proportsional’no kubu tolshchiny ZhK sloya, a dlya DM mod - vozrastaet eksponentsial’no s tolshchinoi ZhK sloev. Pokazano, chto na chastotakh lokalizovannykh mod realizuetsya effekt anomal’no sil’nogo pogloshcheniya (usileniya) v pogloshchayushchikh (usilivayushchikh) kristallakh. Prodemonstrirovano, chto porog lazernoi generatsii v lazerakh s raspredelennoi obratnoi svyaz’yu (ROS) okazyvaetsya nizhe, chem dlya traditsionnoi skhemy lazera, i naideny analiticheskie vyrazheniya dlya porogov na chastote lokalizovannykh mod dlya tolstykh ZhK sloev. Predlozhenie ispol’zovat’ effekt anomal’no sil’nogo pogloshcheniya v ROS lazerakh dlya ponizheniya poroga lazernoi generatsii nashlo svoe eksperimental’noe podtverzhdenie. Ryad drugikh predlozhenii nakhoditsya v stadii eksperimental’noi realizatsii. Poverkhnostnoe stseplenie khiral’nykh ZhK kristallov s poverkhnostyami izuchalos’ eksperimental’no i teoreticheski dlya geometrii klina Kano-Grandzhana, v chastnosti, s tsel’yu opredeleniya istinnogo potentsiala poverkhnostnogo stsepleniya. Kak predvaritel’nyi shag v opredelenii istinnogo potentsiala poverkhnostnogo stsepleniya byl vveden novyi model’nyi potentsial poverkhnostnogo stsepleniya. Provedeny raschety raspredeleniya direktora v kline Kano-Grandzhana dlya razlichnykh modelei potentsiala poverkhnostnogo stsepleniya. Eksperimental’nye izmereniya na klinovidnykh obraztsakh metodom polyarizatsionnoi mikroskopii prodemonstrirovali otlichie real’nogo potentsiala ot shiroko prinyatoi modeli potentsiala Rapini-Populyar i pokazali neobkhodimost’ povysheniya tochnosti izmerenii v issledovaniyakh po vosstanovleniyu istinnogo potentsiala poverkhnostnogo stsepleniya.

Vozdeistvie korotkogo lazernogo impul’sa s energiei fotona v diapazone 1-100 eV na dielektriki i metally

20 January 2012 in 11:30

S.I. Anisimov, N.A. Inogamov, Yu.V. Petrov, V.A. Khokhlov

Korotkii lazernyi impul’s initsiiruet tsepochku fizicheskikh protsessov v obluchennom veshchestve. Naprimer, pri obluchenii rentgenom dielektrika imeet mesto pogloshchenie fotonov vo vnutrennikh elektronnykh obolochkakh, termalizatsiya fotoionizovannykh elektronov v elektronnoi podsisteme i nagrev ionnoi podsistemy za schet peredachi teplovoi energii elektronov v ionnuyu podsistemu. Na bolee pozdnikh stadiyakh stanovyatsya sushchestvenny effekty svyazannye s rekombinatsiei, uravneniem termodinamicheskogo sostoyaniya i gidrodinamikoi, poskol’ku voznikayushchie termomekhanicheskie silovye napryazheniya veliki i privodyat kondensirovannuyu sredu v dvizhenie. Vypolneno molekulyarno-dinamicheskoe modelirovanie rasshireniya tonkogo sloya kristalla LiF posle oblucheniya korotkim lazernym impul’som. Vychislen koeffitsient teploprovodnosti alyuminiya v dvukhtemperaturnom sostoyanii, kogda temperatura elektronov Te velika po sravneniyu s temperaturoi ionov Ti. Pokazano, chto na dvukhtemperaturnoi stadii znacheniya etogo koeffitsienta namnogo prevyshayut tablichnye znacheniya, sootvetstvuyushchie odnotemperaturnomu sluchayu Te=Ti. Proanalizirovano rasprostranenie sverkhzvukovoi volny nagreva i plavleniya i ee transformatsiya v akusticheskuyu volnu szhatiya pri perekhode elektronnoi teplovoi volny iz sverkhzvukovogo v dozvukovoi rezhim rasprostraneniya. Naideno uslovie na amplitudu lazernogo vozdeistviya, v rezul’tate kotorogo obrazuetsya uprugo-plasticheskaya udarnaya volna. Uprugo-plasticheskaya struktura sostoit iz uprugoi udarnoi volny vperedi i sleduyushchei za neyu plasticheskoi udarnoi volny. Pokazano, chto izluchenie uprugoi udarnoi volny proiskhodit pri transzvukovom perekhode volny plavleniya iz sverkhzvukovogo v dozvukovoi rezhim. Izucheno plavlenie i sil’noe vspenivanie zhidkogo sloya zolota pri vozdeistvii korotkogo impul’sa. Vpervye opredeleny prochnostnye kharakteristiki rasplava alyuminiya v zavisimosti ot temperatury zhidkoi fazy. Issledovany ostatochnye nano-deformatsii, voznikayushchie pri vozdeistvii myagkogo rentgenovskogo impul’sa na alyuminievuyu mishen’.

Rayleigh–Taylor instability in a visco-plastic fluid

20 January 2012 in 11:30

A.Yu. Demianov, A.N. Doludenko, N.A. Inogamov, and E.E. Son

The Rayleigh–Taylor and Richtmyer–Meshkov instabilities of a visco-plastic fluid are discussed. The Bingham model is used as an effective rheological model which takes into account plastic effects. For the purposes of numerical simulation a one-mode disturbance of the contact surface between two fluids is considered. The main goal of this work is to construct numerical 2D and 3D models and to obtain the relationship between yield stress and the development of instability.

Sloi rastekaniya pri diskovoi akkretsii na poverkhnost’ neitronnoi zvezdy i problema tormozheniya bystrovrashchayushchegosya veshchestva

20 January 2012 in 11:30

N.A. Inogamov, R.A. Syunyaev

Zadacha o diskovoi akkretsii na poverkhnost’ neitronnoi zvezdy so slabym magnitnym polem pri svetimosti, prevyshayushchei neskol’ko protsentov ot Eddingtonovskoi, svoditsya k probleme tormozheniya giperzvukovogo potoka so skorost’yu 0.4 - 0.5 skorosti sveta nad podoshvoi sloya rastekaniya - plotnoi atmosferoi iz ranee vypavshego veshchestva. V stat’e pokazano, chto turbulentnoe tormozhenie v modeli Prandtlya-Karmana s obshcheprinyatymi dlya zemnykh uslovii i laboratornykh eksperimentov koeffitsientami i lestnitsa iz vzaimodeistvuyushchikh gravitatsionnykh voln v stratifitsirovannoi kvazieksponentsial’noi atmosfere pri standartnykh chislakh Richardsona privodyat k zakruchivaniyu massivnoi zony, prostirayushcheisya do granitsy okeana iz plazmy s vyrozhdennymi elektronami. Turbulentnoe tormozhenie v okeane na granitse s vneshnei tverdoi koroi umen’shaet skorost’ vrashcheniya do skorosti tverdotel’nogo vrashcheniya zvezdy. Takaya kartina dolzhna privodit’ k sil’nomu razogrevu glubokikh sloev atmosfery i vyklyucheniyu mekhanizma vzryvnogo goreniya geliya. Ochevidno, chto v rentgenovskikh barsterakh dolzhen rabotat’ bolee effektivnyi mekhanizm dissipatsii sil’nogo azimutal’nogo techeniya v atmosfere. Pokazano, chto gigantskaya uedinennaya gravitatsionnaya volna v atmosfere sposobna privesti k dissipatsii energii i rezkomu skachkoobraznomu ponizheniyu azimutal’noi skorosti v dostatochno razrezhennykh sloyakh atmosfery nad zonoi termoyadernykh reaktsii vzryvnogo goreniya geliya. Obsuzhdayutsya prichiny vozniknoveniya i ustoichivost’ etoi volny, ne imeyushchei pryamogo analoga v zemnykh atmosfere i okeane.

Vzaimodeistvie brizerov na poverkhnosti dvumernoi zhidkosti

13 January 2012 in 11:30

A.I. D’yachenko

Vzaimodeistvie bizerov ukazyvaet na integriruemost’ uravnenii 2-D gidrodinamiki so svobodnoi granitsei.

Plotnost’ sostoyanii v gryaznykh sverkhprovodyashchikh plenkakh

30 December 2011 in 11:30

M. A. Skvortsov, M. V. Feigel'man

Rassmotren mekhanizm ushireniya plotnosti sostoyanii v neuporyadochennykh sverkhprovodyashchikh plenkakh, obuslovlennyi mezoskopicheskimi fluktuatsiyami. Neodnorodnoe v prostranstve raspredelenie primesei privodit k fluktuatsiyam lokal’nogo polya parametra poryadka, chto v svoyu ochered’ vyzyvaet razmytie kogerentnogo pika v plotnosti sostoyanii i obrazovanie podshchelevykh sostoyanii. Naideny analiticheskie vyrazheniya dlya shiriny oblasti razmytiya i zakona spadaniya plotnosti sostoyanii v podshchelevuyu oblast’. Pokazano, chto uchet kulonovskogo vzaimodeistviya privodit k usileniyu effektov razmytiya kogerentnogo pika. Predskazano sil’noe razmytie plotnosti sostoyanii v okrestnosti kvantovoi kriticheskoi tochki, gde sverkhprovodimost’ ischezaet po fermionnomu stsenariyu.

Fluctuation-dissipation theorem for chiral systems in nonequilibrium steady states

23 December 2011 in 11:30

Dmitri Feldman

We consider a three-terminal system with a chiral edge channel connecting the source and drain terminals. Charge can tunnel between the chiral edge and a third terminal. The third terminal is maintained at a different temperature and voltage than the source and drain. We prove a general relation for the current noises detected in the drain and third terminal. It has the same structure as an equilibrium fluctuation-dissipation relation with the nonlinear response in place of the linear conductance. The result applies to a general chiral system and can be useful for detecting “upstream” modes on quantum Hall edges.

Osobennosti magnitosoprotivleniya v sil’no anizotropnykh sloistykh provodnikakh

16 December 2011 in 11:30

P.D. Grigor’ev

Issledovano magnitosoprotivlenie sil’no anizotropnykh sloistykh metallov v «slabo kogerentnom» rezhime, kogda vremya svobodnogo probega elektronov men’she vremeni ikh mezhsloevogo tunnelirovaniya. Pokazano, chto vopreki sushchestvuyushchei teorii magnitnoe pole vdol’ provodimosti i perpendikulyarnoe provodyashchim sloyam privodit k sil’nomu umen’sheniyu mezhsloevoi provodimosti. Kogda tsiklotronnyi period stanovitsya men’she vremeni svobodnogo probega elektronov v provodyashchem sloe, magnitosoprotivlenie rastet proportsional’no kvadratnomu kornyu ot velichiny magnitnogo polya. Takaya zavisimost’ magnitosoprotivleniya nablyudaetsya vo mnogikh organicheskikh metallakh, naprimer, v $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$, $\kappa -(BEDT-TTF)_{2}Cu(NCS)_{2}$, $\beta ''- (BEDT-TTF)_{4} [(H_{3}O)Fe(C_{2}O_{4})_{3}]C_{5}H_{5}N$ i dr. Pri etom magnitnye kvantovye ostsillyatsii i uglovaya zavisimost’ magnitosoprotivleniya zametno izmenyayutsya. Naprimer, temperatura Dingla rastet proportsional’no kvadratnomu kornyu ot velichiny magnitnogo polya, chto neobkhodimo uchityvat’ pri izvlechenii effektivnoi massy i vremeni rasseyaniya. Dal’neishee uvelichenie magnitnogo polya privodit k eksponentsial’nomu podavleniyu mezhsloevoi provodimosti. Sil’noe magnitnoe pole lokalizuet elektron v provodyashchem sloe na dline poryadka larmorovskogo radiusa. Vokrug takogo lokalizovannogo elektronnogo sostoyaniya obrazuetsya polyaron iz-za elektron - elektronnogo i elektron – fononnogo vzaimodeistviya. Pri mezhsloevom tunnelirovanii elektronov takoi polyaron relaksiruet medlennee vremeni mezhsloevogo pryzhka, chto privodit k vozniknoveniyu kulonovskogo bar’era i eksponentsial’noi temperaturnoi zavisimosti magnitosoprotivleniya. Chem sil’nee magnitnoe pole, tem men’she oblast’ lokalizatsii elektronov i, znachit, tem sil’nee etot kulonovskii bar’er. Poetomu zavisimost’ magnitosoprotivleniya ot magnitnogo polya takzhe okazyvaetsya eksponentsial’noi. Etot effekt sil’no vliyaet na zavisimost’ mezhsloevoi elektronnoi provodimosti kak ot velichiny, tak i ot napravleniya magnitnogo polya, a takzhe privodit k rezkomu usileniyu magnitnykh kvantovykh ostsillyatsii mezhsloevoi provodimosti.

Publikatsii: 1. P.D. Grigoriev, “Weakly incoherent regime of interlayer conductivity in magnetic field”, Phys. Rev. B 83, 245129 (2011). 2. P. D. Grigoriev, “Monotonic growth of interlayer magnetoresistance in strong magnetic field in very anisotropic layered metals”, JETP Lett. 94, 47 (2011). 3. P.D. Grigoriev, “New features of magnetoresistance in the strongly anisotropic layered metals”, Low Temperature Physics/Fizika Nizkikh Temperatur 37 (9-10), 930 (2011). 4. P. D. Grigoriev, “Exponential suppression of interlayer conductivity in very anisotropic quasi-two-dimensionalcompounds in high magnetic field”, Physica B (prinyato v pechat’); ArXiv: sond-mat/1111.2432

Ekzoticheskie iony v zhidkom gelii

9 December 2011 in 11:30

A.M. Dyugaev, P.D. Grigor’ev, E.V. Lebedeva

Na primere Ar-, Kr-, Xe- rasshiren katalog otritsatel’nykh ionov v sverkhtekuchem gelii. Takie ob’ekty ne mogut sushchestvovat’ v vakuume, tak kak polyarizatsionnogo prityazheniya elektrona k inertnomu atomu A ne khvataet dlya formirovaniya svyazannogo sostoyaniya A-; odnako v gelii eti ob’ekty sushchestvuyut kak stabil’nye ili metastabil’nye s ochen’ bol’shim vremenem zhizni. Effekt svyazan s lokalizatsiei elektrona v zhidkom gelii. Esli v gazovoi faze nad zhidkim geliem sformirovat’ smes’ vozbuzhdennykh atomov A* i elektronov, vozmozhna reaktsiya A*+e= A$^{*-}$, kotoraya idet dlya vsekh atomov A tablitsy Mendeleeva. Takie zaryady mogut byt’ vnedreny v zhidkii gelii elektricheskim polem. Pri etom radiatsionnyi raspad A$^{*-}=$ A$+e$, vozmozhnyi v vakuume, mozhet byt’ zapreshchen v zhidkosti. Eto privodit k formirovaniyu novykh unikal’nykh ob’ektov A-, kotorye mogut sushchestvovat’ v zhidkom gelii, no ne vstrechayutsya v prirode. Opredelen razmer ukazannykh zaryazhennykh obrazovanii, kotoryi mozhet malo otlichat’sya ot radiusa obychnogo puzyr’kovogo sostoyaniya elektrona v gelii. Takzhe opredeleny svoistva elektronnykh puzyr’kov, prizhatykh silami elektrostaticheskogo izobrazheniya k granitse razdela zhidkogo He3 s nasyshchennym rastvorom He4 - He3 v oblasti nizkikh temperatur. Ravnovesnoe sostoyanie takikh ob’ektov kharakterizuetsya energiei svyazi 6.5 K. Smeshchayushchee elektricheskoe pole E=100 V/cm pri temperature T=0.2 K privodit k raspadu svyazannogo puzyr’kovogo sostoyaniya so vremenem zhizni ~1 sek. Eksperimental’noe izuchenie puzyr’kovykh elektronnykh sostoyanii mozhet okazat’sya poleznym dlya opredeleniya svoistv granitsy razdela rastvorov zhidkogo geliya.

Publikatsii: 1. A.M. Dyugaev, P.D. Grigor’ev, E.V. Lebedeva, «Otritsatel’nye iony Ar-, Kr-, Xe- v sverkhtekuchem gelii», Pis’ma v ZhETF, 94(9), 774 (2011) (2011). 2. A.M. Dyugaev, P.D. Grigoriev, E.V. Lebedeva, «Negative Ions on the interface of liquid helium solutions», Fizika Nizkikh Temp. 37 (9-10), 1008 (2011).

Uporyadochennye fazy i fazovye perekhody vo frustrirovannoi XY modeli na sotovoi reshyotke

2 December 2011 in 11:30

S.E. Korshunov

Pokazano, chto fazovaya diagramma maksimal’no frustrirovannoi XY modeli na sotovoi reshyotke soderzhit tri razlichnykh uporyadochennykh fazy. V naibolee neobychnoi iz nikh dal’nii poryadok svyazan ne s formirovaniem opredelyonnoi periodicheskoi struktury iz yacheek s raznymi znakami zavikhrennosti, a s nalichiem predpochtitel’noi orientatsii domennykh stenok s nulevoi energiei, razdelyayushchikh domeny s razlichnymi periodicheskimi strukturami. Fazovyi perekhod, privodyashchii k razrusheniyu takogo sostoyaniya, sostoit v poyavlenii svobodnykh drobnykh vikhrei i proiskhodit pervym rodom. Stabilizatsiya dvukh drugikh uporyadochennykh faz (sushchestvuyushchikh pri bolee nizkikh temperaturakh) obuslovlena tem, chto pri prisutstvie spinovykh voln pridayot obladayushchim nulevoi energiei domennym stenkam polozhitel’nuyu svobodnuyu energiyu. Etot effekt imeet ves’ma sushchestvennuyu chislennuyu malost’, poetomu nablyudenie sootvetstvuyushchikh faz vozmozhno lish’ pri makroskopicheskikh razmerakh obraztsa. Odnako, v fizicheskikh sistemakh (takikh, kak frustrirovannye magnitnym polem reshyotki dzhozefsonovskikh kontaktov i setki iz sverkhprovodyashchikh provolok) prisutstvie dopolnitel’nykh vzaimodeistvii dolzhno privodit’ k uluchsheniyu vozmozhnostei nablyudeniya fazy s regulyarnym cheredovaniem polozhitel’nykh i otritsatel’nykh vikhrei.

Coherent resonance accumulation of the EDM signal at magnetic storage rings

2 December 2011 in 11:30

W.Morse (BNL), N. Nikolaev, F. Rathmann (IKP FZJ)

Permanent EDM of particles and light nuclei is one of the keys to understanding the origin of CP violation and, eventually, of the baryogenesis in our Universe. We describe some unexpected features of spin dynamics in magnetic storage rings supplemented with radiofrequency electric EDM flippers. We report an evalutaion of the spin decoherence time and a finding of magic energies at which the spin diffusion vanishes.

Bases in 2d conformal field theory and instanton moduli spaces

25 November 2011 in 11:30

A.A. Belavin, M.A. Bershtein, B.L. Feigin, A.V. Litvinov, G.M. Tarnopolskiy

Part 2

Bases in 2d conformal field theory and instanton moduli spaces

18 November 2011 in 11:30

A.A. Belavin, M.A. Bershtein, B.L. Feigin, A.V. Litvinov, G.M. Tarnopolskiy

Recently proposed relation between conformal field theories in two dimensions and supersymmetric gauge theories in four dimensions predicts the existence of the distinguished basis in the space of local fields in CFT. This basis has a number of remarkable properties, one of them is the complete factorization of the coefficients of the operator product expansion. We consider a particular case of the U(r) gauge theory on C2/Zp which corresponds to a certain coset conformal field theory and describe the properties of this basis. We argue that in the case p=2, r=2 there exist different bases. We give an explicit construction of one of them. For another basis we propose the formula for matrix elements.

Transportnye svoistva kontaktov sverkhprovodnikov s topologicheskimi izolyatorami

18 November 2011 in 11:30

N.M. Shchelkachev

Iskhodya iz mikroskopicheskikh uravnenii, vyveden effektivnyi gamil’tonian dvumernoi gibridnoi struktury sverkhprovodnik – dvumernyi topologicheskii izolyator. Pokazano, chto effektivnyi gamil’tonian blagodarya sverkhprovodyashchemu effektu blizosti soderzhit chleny, peremeshivayushchie podzony topologicheskogo izolyatora. Vsledstvie etogo, v spektre kraevykh sostoyanii otkryvaetsya shchel’, zavisyashchaya ot orientatsii granitsy, chto privodit k andreevskoi lokalizatsii kraevykh sostoyanii s dostatochno maloi energiei. Pokazano, chto v rezhime sil’noi svyazi mezhdu sverkhprovodnikom i topologicheskim izolyatorom shchel’ v ob’eme topologicheskogo izolyatora pochti polnost’yu propadaet.

Localized Majorana state on a disordered surface of a topological insulator

11 November 2011 in 11:30

P. A.Ioselevich, P. M.Ostrovsky, M. V. Feigel'man

We found density of states on a free surface of disordered topological insulator surrounded by a superconductor, in presense of a single-quantum vortex. The problem is shown to be in the B class of the Altland-Zirnbauer classification. Spatial dependence of the low-energy density of states is found. Tunnel current seen by STM i s calculated as function of the voltage.

Neravnovesnaya kvantovaya dinamika sil’nokorellirovannykh ul’trakholodnykh atomov v opticheskikh reshetkakh

28 October 2011 in 11:30

E.A. Demler, A.Ya. Mal’tsev, A.O. Prokof’ev

Rassmatrivayutsya voprosy neravnovesnoi dinamiki bozonnykh reshetok s reshetochnymi gamil’tonianami spinovogo tipa. Ispol’zuetsya kvaziklassicheskoe opisanie dlya analiza prirody solitonnykh reshenii, pri etom my pokazyvaem, chto v zavisimosti ot mikroskopicheskikh parametrov oni mogut opisyvat’sya rezhimami KdF, mKdF ili NUSh. Analiziruetsya zadacha dinamicheskoi evolyutsii nachal’nogo sostoyaniya s neodnorodnoi plotnost’yu, pri etom privoditsya dinamicheskaya fazovaya diagramma, vklyuchayushchaya analiz rezhimov obrazovaniya i ustoichivosti odnomernykh solitonov, a takzhe rezhimov oboazovaniya mnogomernykh “lump” reshenii.

Faddevskie sobstvennye funktsii dvumernogo tochechnogo potentsiala

21 October 2011 in 11:30

P.G. Grinevich, R.G. Novikov

Razvitaya k nastoyashchemu vremeni tekhnika resheniya obratnykh zadach rasseyaniya dlya dvumernoi kvantovoi ili akusticheskoi zadachi pri odnoi energii khorosho rabotaet v predpolozhenii, chto u sobstvennykh funktsii Faddeevskogo tipa net osobennostei po spektral’nomu parametru na mnogoobrazii dannoi energii. Esli potentsial dostatochno velik, vozniknovenie takikh osobennostei neizbezhno (naprimer, esli my rabotaem pri otritsatel’noi energii vyshe osnovnogo sostoyaniya, osobennosti vsegda est’ – Grinevich, S.P. Novikov). Pri etom v tipichnoi situatsii voznikayut obobshchenno-analiticheskie funktsii s osobennostyami na liniyakh, teoriya kotorykh k nastoyashchemu vremeni sovershenno ne razvita. Odna iz problem – otsutstvie tochno reshaemykh primerov. My pokazyvem, chto dlya dvumernykh tochechnykh potentsialov (analogichnye potentsialy v trekhmerii izuchalis’ Zel’dovichem i Berezinym-Faddeevym) vse volnovye funktsii yavno vychislyayutsya, kak i mnogoobrazie osobennostei a takzhe obobshchennye dannye rasseyaniya. My raschityvaem, chto dannyi tochno reshaemyi primer pomozhet naiti pravil’nuyu postanovku obratnoi zadachi rasseyaniya v prisutstvii singulyarnykh konturov.

Poverkhnostnyi impedans v sverkhprovodnikakh so slabymi magnitnymi primesyami

14 October 2011 in 11:30

Ya.V. Fominov, M. Houzet, L.I. Glazman

Magnitnye primesi izmenyayut spektr vozbuzhdenii v sverkhprovodnike i poetomu vliyayut na impedans. My interesuemsya dissipativnoi chast’yu poverkhnostnogo impedansa. Issledovana zavisimost’ impedansa ot chastoty, kontsentratsii magnitnykh primesei i ikh sily, i ot kontsentratsii kvazichastits (temperatury). Dazhe malaya kontsentratsiya slabykh magnitnykh primesei sushchestvenno menyaet spektr vozbuzhdenii vblizi shcheli BKSh. Poetomu osoboe vnimanie udeleno porogovomu povedeniyu pri nulevoi temperature, a takzhe nizkochastotnomu pogloshcheniyu za schet kvazichastits. (arXiv:1110.1370)

Opisanie kvantovogo elektronnogo transporta s pomoshch’yu matrits rasseyaniya

7 October 2011 in 11:30

G. B. Lesovik, I. A. Sadovskii

V obzore podrobno rassmatrivaetsya primenenie matrits rasseyaniya v teorii kvantovogo elektronnogo transporta v mezo- i nano- provodnikakh. Opisyvaemyi podkhod al’ternativen bolee privychnomu podkhodu s ispol’zovaniem kineticheskogo uravneniya ili funktsii Grina, i dlya kogerentnykh provodnikov chasto effektivnee (osobenno dlya dokazatel’stva obshchikh sootnoshenii) i pochti vsegda naglyadnee. Rassmotreno kak opisanie srednikh po vremeni velichin (tipa vol’tampernykh kharakteristik provodnikov), tak i fluktuatsii toka vo vremeni shuma, a takzhe polnoi statistiki perenosa zaryada za konechnoe vremya. Krome normal’nykh provodnikov rassmotreny kontakty so sverkhprovodnikami, a takzhe dzhozefsonovskie kontakty. (Po materialam obzora v UFN, oktyabr’ 2011)

Quantum tops as examples of commuting differential operators

7 October 2011 in 11:30

A.B. Shabat, V.E. Adler, V.G. Marikhin

We study the quantum analogs of tops on Lie algebras $so(4)$ and $e(3)$ represented by differential operators.

Trekhmernye effekty v dinamike anomal’nykh morskikh voln: chislennoe issledovanie

30 September 2011 in 11:30

V.P. Ruban

Obsuzhdayutsya nedavnie rezul’taty chislennogo modelirovaniya polnost’yu nelineinykh evolyutsionnykh uravnenii dlya dlinno-grebnevykh voln na glubokoi vode, pri kotorom nablyudalos’ samoproizvol’noe obrazovanie ekstremal’no vysokikh voln — t. n. voln-ubiits. Na neskol’kikh primerakh pokazano, chto trekhmernost’ dvizheniya zhidkosti ves’ma sushchestvennym obrazom vliyaet na protsess poyavleniya anomal’nykh voln. V chastnosti, pri nalichii uzkikh i dlinnykh volnovykh grupp naibolee vysokie volny-ubiitsy voznikayut v tom sluchae, kogda v nachal’nom sostoyanii volnovye fronty orientirovany pod uglom k napravleniyu gruppy. “Optimal’nyi” ugol orientatsii grebnei, privodyashchii k naibol’shim volnam, zavisit ot nachal’noi volnovoi amplitudy i ot shiriny gruppy, i sostavlyaet 18–28 gradusov v prakticheski vazhnoi oblasti parametrov. Krome togo, promodelirovan mekhanizm prostranstvenno-vremennoi fokusirovki na fone kvazisluchainogo nelineinogo volnovogo polya pri raznykh znacheniyakh nelineinosti i vremeni fokusirovki.

On the spectra of inverse cascade in the presence of condensate: numerical experiment

30 September 2011 in 11:30

Alexander Korotkevich

Level statistics of disordered spin-1/2 systems and its implications for materials with localized Cooper pairs.

23 September 2011 in 11:30

Emilio Cuevas, Mikhail Feigel'man , Lev Ioffe and Marc Mezard

Origin of continuous energy spectrum in a large disordered interacting quantum system is one of the key unsolved problems in quantum physics. While small quantum systems with discrete energy levels are noiseless and stay coherent forever in the absence of any coupling to external world, most large-scale quantum systems are able to produce thermal bath and excitation decay. The important question is what is the driving force and the mechanism of transition(s) between two different types of many-body systems - with and without intrinsic decoherence? Here we address this question via the numerical study of energy level statistics of a system of spins-1/2 with anisotropic exchange interaction and random transverse field. Our results present first evidence for a well-defined quantum phase transition between domains of discrete and continous many-body spectra in a class of random spin models. Because these models also describes the physics of superconductor-insulator transition in InO and similar materials our results imply the appearance of novel insulating phases in the vicinity of the transition.

Bosonic analog of the electron bubble: ground-state and non-ground-state BEC of magnons in superfluid 3He-B

16 September 2011 in 11:30

G. Volovik

Long-lived coherent spin precession of 3He-B observed at temperatures around 0.2 Tc is interpreted to represent Bose-Einstein condensation of spin wave excitations or magnons in a magnetic trap which is formed by the orbital texture of order parameter. When the number of magnons increases, they via spin-orbit interaction exert an orienting influence on the orbital texture. Since the texture is very flexible the potential well produced by texture is crucially modified leading to self-localization of magnon BEC. The scenario of self-localization represents the bosonic analog of formation of the electronic bubble in helium liquids, where an injected electron opens a cavity whose size is determined by a balance between the zero-point energy of the electron and the surface energy of the bubble. In our case the role of the electron wave function is played by the condensate wave function of magnon BEC, while the role of the liquid environment is played by the orbital texture, which is expelled from the bubble due to spin-orbit interaction. The bubble free from texture can be filled either with the magnon condensate in the ground states, or with BEC on any excited level. The BEC in a given excited state is populated and sustained by continuous rf pumping at its specific excitation frequency. On switching off the pumping the magnons from an excited level BEC drop to the ground state BEC.

Motion of near-spherical micro-capsule in planar external flow

9 September 2011 in 11:30

S.S. Vergeles and P.E. Vorobev

Dynamics of a micro-capsule with compressible membrane placed into planar flow is considered. The form of the capsule is assumed to be near-spherical and the membrane forces are calculated in the first order in respect to the membrane displacement. We have established that the capsule dynamics is governed by two dimensionless parameters in this limit, which account for membrane stretch nodulus, viscosities if inner fluid and solvent, capsule radius, external flow gradient and Taylor deformation parameter at rest. Phase diagram for capsule dynamical regimes is plotted on the plane of these two dimensionless parameters in the limits of high and low viscosity contrasts between the fluid inside the capsule and the solvent.

Magnetic-field-driven quantum phase transitions in unconventional Josephson arrays

2 September 2011 in 11:30

Joshua Paramanandam, Matthew Bell, and Michael Gershenson (Rutgers University, USA)

Arrays of nanoscale Josephson junctions represent an important tool in the exploration of several fundamental problems of the physics of quantum disordered systems, including quantum phase transitions in systems with and without long-range interactions, emergent glassy behavior, and formation of topological phases. The fabrication of novel types of Josephson arrays with unconventional geometries is required to address these issues. We report on the study of low-temperature transport in the arrays with a large number of nearest-neighbor elements. Both linear and non-linear effects in such arrays will be discussed, including the superconductor-insulator transition, an activation transport in the insulating regime, and the threshold for dissipative transport.

Logarithmic scaling of the critical collapse of Keller-Segel equation

24 June 2011 in 11:30

Pavel Lushnikov

Keller-Segel equation (KS) is a parabolic-elliptic system of partial differential equations with applications to bacterial aggregation and collapse of self-gravitating gas of brownian particles. KS has striking qualitative similarities with nonlinear Schrodinger equation including critical collapse (finite time point-wise singularity) in two dimensions and supercritical collapse in three dimensions. The self-similar solutions near blow up point are studied for KS in critical case together with time dependence of these solutions and their stability. We found logarithmic-type modifications to (t0-t)1/2 scaling law of self-similar solution in qualitative analogy with log-log corrections for NLS. Very good agreement is achieved between the direct numerical simulations of KS with the analytical results by developing a perturbation theory for logarithmic-type modifications. It suggests that log-log corrections in NLS also could be verified in a similar way.

Instantons and the correlation functions in Super-Liouville theory

17 June 2011 in 11:30

A.A. Belavin

Dvumernaya teoriya Super-Liuvillya voznikaet pri kvantovanii teorii strun v nekriticheskoi razmernosti prostranstva-vremeni. My ispol’zuem zamechatel’nuyu svyaz’ mezhdu instantonami v chetyrekhmernykh kalibrovochnykh teoriyakh polya i dvumernymi konformnymi teoriyami polya dlya postroeniya yavnogo vida konformnogo bloka v 2D teorii Super-Liuvillya.

Three-point correlation function in parafermionic Liouville field theory

10 June 2011 in 11:30

Mikhail Bershtein

Vychislyaetsya trekhtochechechnaya funktsiya v ZN parafermionnoi teorii Liuvillya. Rezul’tat yavlyaetsya obobshcheniem izvestnykh formul dlya N=1 (Dorn, Otto, Zamolodchikov, Zamolochdikov) i N=2 (Rashkov, Stanichkov, Pogosyan). Vychislenie privodit k zadache iz teorii mnogochlenov kotoraya reshaetsya pri pomoshchi vvedeniya spetsial’noi fil’tratsii na prostranstve simmetrichnykh mnogochlenov.

Topological bound states in 3D media with Weyl points: 1D flat band on the vortex axis and Fermi arc on the surface

3 June 2011 in 11:30

G. Volovik

Topological semimetals first discussed by Abrikosov and Beneslavskii ("Possible existence of substances intermediate between metals and dielectrics", JETP 32 (1971) 699-708) have topologically protected point nodes. Close to that points, electrons behave as Weyl fermions. Later it became clear that the same Weyl points exist in superfluid 3He-A and in the vacuum of Standard model. As in topological insulators, in the topological systems with Weyl fermions there is the bulk-surface and the bulk-vortex correspondence. Due to bulk-vortex correspondence, the core of the 3He-A vortex contains the 1D flat band first found by Kopnin in 1991. The end points of this flat band are determined by projections of the Weyl points to the vortex axis. Due to bulk-surface correspondence, the surface of 3He-A and of 3D topological semimetals contains the Fermi arc - the 1D Fermi line in the 2D momentum space at which fermions have zero energy. The end points of the Fermi arc are determined by projections of the Weyl points to the surface.

Vikhrevaya reshetka v bystro vrashchayushchemsya Boze-kondensate. Struktura, vozbuzhdeniya, korrelyatsionnye funktsii

27 May 2011 in 11:30

S. Matveenko

Ispol’zuya naidennye ranee resheniya uravneniya Grossa-Pitaevskogo dlya vikhrevoi struktury, polucheno tochnoe reshenie uravnenii Bogolyubova-de Zhena dlya vozbuzhdenii vikhrevoi reshetki v bystro vrashchayushchemsya Boze-kondensate. Vychisleny koeffitsient zatukhaniya kvazichastits, matritsa plotnosti pri nulevoi i konechnoi temperaturakh.

Vliyanie statistiki odnoelektronnogo energeticheskogo spektra na spinovye i zaryadovye korrelyatsii v kvantovykh tochkakh

20 May 2011 in 11:30

I.S. Burmistrov, Yuval Gefen (Weizmann Institute, Israel), Mikhail Kiselev (ICTP, Italy)

Izuchen vopros o vliyanii statistiki odnoelektronnogo energeticheskogo spektra elektronov na yavlenie mezoskopicheskoi stounerovskoi neustoichivosti v izolirovannoi kvantovoi tochke s pryamym i obmennym vzaimodeistviyami. Vblizi stounerovskoi neustoichivosti vychislena srednyaya magnitnaya vospriimchivost’ v shirokom intervale temperatur.

Vysokotemperaturnaya poverkhnostnaya sverkhprovodimost’ v mnogosloinom romboedricheskom grafene

13 May 2011 in 11:30

N.B. Kopnin, T.T. Heikkilä (Low Temperature Laboratory, Aalto University, Finland), and G.E. Volovik

Pokazano, chto topologicheski zashchishchennaya ploskaya zona, poyavlyayushchayasya na poverkhnosti sloistoi sistemy fermionov s liniyami nulei v spektre, sposobstvuet vozniknoveniyu poverkhnostnoi sverkhprovodimosti blagodarya beskonechno bol’shoi plotnosti sostoyanii v ploskoi zone. Kriticheskaya temperatura poverkhnostnoi sverkhprovodimosti pryamo proportsional’na velichine kuperovskogo vzaimodeistviya i, sledovatel’no, znachitel’no bol’she kriticheskoi temperatury v ob’eme. V kachestve konkrentnogo primera rassmotrena mnogosloinaya sistema grafena s romboedricheskoi upakovkoi.

Rezkoe povyshenie elektronnogo davleniya v rezul’tate pogloshcheniya ul’trakorotkogo lazernogo impul’sa i ablyatsiya s poverkhnosti metalla pod deistviem etogo davleniya

6 May 2011 in 11:30

N.A. Inogamov, V.A. Khokhlov, V.V. Zhakhovskii

Pogloshchenie ul’trakorotkogo lazernogo impul’sa v metallakh privodit k sil’nomu peregrevu elektronov otnositel’no ionov (Te >> Ti) i k povysheniyu elektronnogo davleniya pe v poverkhnostnom sloe misheni. Naibol’shie znacheniya pe dostigayutsya u granitsy metall-vakuum, gde temperatura elektronov Te maksimal’na. V rabote izuchena dinamika ablyatsii pri davleniyakh pe, kotorye prevoskhodyat dinamicheskuyu prochnost’ metalla plim na razryv (v nashikh usloviyakh plim ~ 5-15 GPa). Togda na stadii elektron-ionnoi temperaturnoi relaksatsii (t.e. poka vypolnyaetsya uslovie Te >> Ti) rasshirenie proiskhodit v volne razleta, v kotoroi veshchestvo misheni perekhodit iz kondensirovannogo sostoyaniya v plotnyi gaz pri peresechenii fronta skachka s ponizheniem plotnosti. Esli v kondensirovannoi faze atomy svyazany drug s drugom khimicheskimi svyazyami, to za skachkom takie svyazi razorvany. Desorbtsiya elektronnym davleniem na granitse kondensirovannoi fazy yavlyaetsya novym mekhanizmom lazernoi ablyatsii. Kak pokazyvayut raschety, otnositel’no nebol’shie temperatury Te ~ 1-2 eV i svyazannye s nimi davleniya pe ~ 10 GPa dostatochny dlya vozniknoveniya takogo rezhima ablyatsii.

On a discrete analog of the Tzitzeica equation

29 April 2011 in 11:30

V.E. Adler

An integrable discrete analog of the Tzitzeica equation is found in the form of a partial difference equation on the square grid. Its higher continuous symmetry is an inhomogeneous Volterra-Narita-Bogoyavlensky type lattice equation. It defines a discretization of the Sawada-Kotera equation (KdV-like equation of 5-th order). The integrability of these discretizations is proven by construction of the Lax representations. From the geometric point of view, the Lax representation is a discrete version of Gauss equations for affine spheres. The bilinear equations for the tau-function are derived.

Hopping conductance in the presence of electro-magnetic fields

22 April 2011 in 11:30

Zvi Ovadyahu (Jerusalem University)

When exposed to sufficiently strong electro-magnetic (EM) fields, the conductance of hopping systems is enhanced. Data taken on six different hopping systems will be shown to illustrate that in the microwaves (MW) regime, the excess conductance is sub-linear with the EM power. It can be demonstrated that the effect is not due to heating. The mechanism for the conductance enhancement will be presented and the implications to some general features of Anderson insulators will be discussed.


Form Factors in the Ising Model in Magnetic Field at T=Tc

15 April 2011 in 11:30

Oleg Alekseev

We consider the scaling limit of the two-dimensional Ising Model in a Magnetic Field at T=Tc (IMMF). This model is known to be an integrable QFT whose spectrum and the exact S-matrix is described by the E8 scattering theory. The correlation functions of local operators can be computed within the Form Factor approach. Using the remarkable connection between the IMMF and the Bullough-Dodd model in the framework of the free field representation we obtain exact form factors of local operators in the IMMF. We obtain the recurrent relation which establishes relation between form factors with a different number of particles and provides a convenient procedure for explicit evaluation of the form factors.

Nepreryvnaya interpolyatsiya mezhdu frustrirovannym Izingom i kvantovymi dimernymi modelyami

8 April 2011 in 11:30

S.E. Korshunov

We propose a new quantum model interpolating between the fully frustrated spin 1/2 Ising model in a transverse field and a dimer model. This model contains a resonating-valence-bond phase, including a line with an exactly solvable ground state of the Rokhsar-Kivelson type. We discuss the phase diagrams of this model on the square and triangular (in terms of the dimer representation) lattices [D. A. Ivanov and S. E. Korshunov, arXiv:1102.1912].

Nodal topological matter and flat bands

1 April 2011 in 11:30

G.E. Volovik

Topological media are systems whose properties are protected by topology and thus are robust to different perturbations of the system including as the change of the parameters of interaction. In topological insulators, and in the nodeless topological superconductors and superfluids the bulk-surface and bulk-vortex correspondence gives rise to the gapless Dirac or Majorana fermions on the surface of the system or inside the vortex core. In gapless topological media, the bulk-surface and bulk-vortex correspondence is even more interesting: it produces topologically protected gapless fermions without dispersion - the flat band. Fermion zero modes forming the flat band are localized on the surface of topological media with protected nodal lines and in the vortex core in systems with topologically protected Dirac points, such as superfluid 3He-A. Flat band has an extremely singular density of states. This property may give rise in particular to surface superconductivity with an unusually high transition temperature thus opening a possible route for room temperature superconductivity.

Elastic-plastic phenomena and propagetion of strong shock wawes under the acion of femtosecond laser pulses

18 March 2011 in 11:30

V.A. Khokhlov, N.A. Inogamov, V.V. Zhakhovskii

The splitting of the shock wave (SW) on the elastic precursor and a plastic wave — a characteristic phenomenon that appears only in solid media. Recently, numerical calculations and femtosecond laser experiment revealed the existence of an elastic shock wave at pressure p ~ 10 GPa, 1-2 orders of magnitude greater than the dynamic elastic limit .In these ultra-short waves is not enough time to form a plastic shock wave. In this paper we analyzed the formation and propagation of elastic and plastic waves in aluminum at still higher pressures, obtained with femtosecond lasers. It is found that the elastic precursor survives even in circumstances where the pressure after a plastic front comes up huge quantities p ~ 1 Mbar, at which the melting of the metal. It is shown that the account of superelasticity is required for proper interpretation of the previous laser experiments.

Ablation of lithium fluoride dielectric crystal by the short pulses of x-ray plasma laser and extreme ultraviolet free electron laser.

18 March 2011 in 11:30

Anisimov S.I., Faenov A.Yu., Inogamov N.A., Khokhlov V.A., Petrov Yu.V., Skobelev I.Yu., Zhakhovskii V.V.

We presented experimental and theoretical studies of ablation of condensed matter by extreme ultraviolet (EUV) and X-ray lasers (XRL). Results obtained by the use of two different soft XRL are compared. The first XRL is the collision Ag-plasma laser with pulse duration 7 ps and laser photon energy 89.3 eV, while the second one is EUV free electron laser (EUV-FEL) with pulse duration 0.3 ps and energy of photon 20.2 eV. Investigation of interaction of irradiation from these two types of XRL with the wide gap lithium fluoride (LiF) dielectric shows that ablation thresholds in both cases are approximately the same. Ablation threshold for XRL interacting with dielectric appears to be significantly lower than the threshold of ablation when ultrashort laser pulse of optical frequency range interacts with the metal surface. The similarity between the two XRL is due to the short pulse durations of both XRL. They are shorter than, or comparable with the acoustic time, which is necessary for sound to travel through an attenuation depth. These short pulses create thermomechanical stresses which are the reason for spallative ablation in the dielectric as well as it takes place in metals. Thermomechanics and negative pressure define character of ablation at relatively low fluences of the order of ablation threshold. At such fluences, heating is moderate and matter remains in condensed state where cohesive properties are dynamically important. At higher fluences, XRL transfers the heated layer into the gaseous state where cohesion phenomenon is not significant. A theory presented explains a slow growth of ablated mass with a fluence when the short X-ray laser irradiation interacts with the dielectric target as a result of transition from the spallative ablation near threshold value of a fluence to the evaporative ablation at high fluences.

Magneto-optics of graphite in quantizing magnetic fields

11 March 2011 in 11:30

L.A. Falkovsky

The optical conductivity of graphite in quantizing magnetic fields is analytically evaluated applying the Slonczewski–Weiss–McClure model with the trigonal warping including in the Hamiltonian. Both the dynamical conductivities, longitudinal as well as Hall's, are calculated. The conductivity peaks are explained in terms of the electron transitions in graphite. The conductivities describe the absorption and the Kerr rotation.

Enhancement of superconductivity by Anderson localization

4 March 2011 in 11:30

I.S. Burmistrov

Influence of disorder on the temperature of superconducting transition (Tc) is studied within the sigma-model renormalization group framework. Electron-electron interaction in particle-hole and Cooper channels is taken into account and assumed to be short-range. Two-dimensional systems in the weak localization and antilocalization regime, as well as systems near mobility edge are considered. It is shown that in all these regimes the Anderson localization leads to strong enhancement of Tc related to the multifractal character of wave functions.

Quantum Abacus for counting and factorizing numbers

4 March 2011 in 11:30

M. V. Suslov, G. B. Lesovik, G. Blatter

We generalize the binary quantum counting algorithm of Lesovik, Suslov, and Blatter [Phys. Rev. A 82, 012316 (2010)] to higher counting bases. The algorithm makes use of qubits, qutrits, and qudits to count numbers in a base 2, base 3, or base d representation. In operating the algorithm, the number n < N = d^K is read into a K-qudit register through its interaction with a stream of n particles passing in a nearby wire; this step corresponds to a quantum Fourier transformation from the Hilbert space of particles to the Hilbert space of qudit states. An inverse quantum Fourier transformation provides the number n in the base d representation; the inverse transformation is fully quantum at the level of individual qudits, while a simpler semi-classical version can be used on the level of qudit registers. Combining registers of qubits, qutrits, and qudits, where d is a prime number, with a simpler single-shot measurement allows to find the powers of 2, 3, and other primes d in the number n. We show, that the counting task naturally leads to the shift operation and an algorithm based on the quantum Fourier transformation. We discuss possible implementations of the algorithm using quantum spin-d systems, d-well systems, and their emulation with spin-1/2 or double-well systems. We establish the analogy between our counting algorithm and the phase estimation algorithm and make use of the latter's performance analysis in stabilizing our scheme. Applications embrace a quantum metrological scheme to measure a voltage (analog to digital converter) and a simple procedure to entangle multi-particle states. ( arXiv:1011.3646 )

Relaksatsionnaya teoriya klimata

25 February 2011 in 11:30

A.V. Byalko

Dannye, poluchennye pri burenii antarkticheskikh l’dov, predstavlyayut soboi zapisi temperatury i kontsentratsii dioksida ugleroda SO2 i metana SN4 za proshlye 800 tysyach let [1, 2]. Standartnymi metodami matematicheskii analiza byli vychisleny avto- i inter-korrelyatsionnye funktsii trekh sluchainykh funktsii vremeni: T(t), [CO2](t), [CH4](t) [3], a takzhe ikh raspredeleniya i regressii. V techenie vos’mi 100-tysyacheletnikh tsiklov Milankovicha put’ zavisimosti T([CO2]) priblizhenno povtoryaetsya, chto daet osnovanie predpolagat’ nalichie oblasti ustoichivosti. Resheniya uravnenii relaksatsii k krivoi ravnovesiya (regressii) pozvolyayut poluchit’ fizicheski opravdannye priblizheniya: 1) sovremennogo rosta kontsentratsii CO2 po dannym potrebleniya uglya, nefti, gaza; 2) sovremennogo rosta temperatury po dannym rosta kontsentratsii CO2; 3) budushchikh izmenenii temperatury i kontsentratsii CO2 v zavisimosti ot stsenariya energopotrebleniya; 4) potokov energii mezhdu poverkhnostnym sloem okeana i ego glubinami za 800 tysyach let. [1]. Lüthi, D. et al. High-Resolution Carbon Dioxide Concentration Record 650.000—800.000 Years before Present, Nature, 2008, V. 453, pp. 379-382. [2]. Loulergue, L. et al. Orbital and Millennial-Scale Features of Atmospheric CH4 Over the Past 800.000 Years, Nature, 2008, V. 453, pp. 383-386. [3]. Byalko A.V. Paleoklimat: dopolneniya k teorii Milankovicha, Priroda, 2009, №12, s. 18-28.

Fazovaya diagramma frustrirovannoi modeli Izinga s poperechnym magnitnym polem i sotovoi reshyotkoi

18 February 2011 in 11:30

C. E. Korshunov

Motivated by the current interest in the quantum dimer model on the triangular lattice, we investigate the phase diagram of the closely related fully-frustrated transverse field Ising model on the honeycomb lattice using classical and semi-classical approximations. We show that, in addition to the fully polarized phase at large field, the classical model possesses a multitude of phases that break the translational symmetry which, in the dimer language, correspond to a plaquette phase and a columnar phase separated by an infinite cascade of mixed phases. The modification of the phase diagram by quantum fluctuations has been investigated in the context of linear spin-wave theory.

Rezonansy v modelyakh sh- i sin-Gordona i vysshie uravneniya dvizheniya v teorii Liuvillya

11 February 2011 in 11:30

Mikhail Lashkevich

Высшие уравнения движения в квантовой теории поля Лиувилля, предложенные Ал. Замолодчиковым, интерпретированы как резонансы в конформной теории возмущений от модели свободного безмассового поля. Оператор, отвечающий нуль-вектору в представлении конформной алгебры, находится в резонансе с одним из экспоненциальных операторов. Под резонансом подразумевается ситуация, когда при определенных соотношениях между конформными размерностями полей возникают логарифмические ультрафиолетовые расходимости во всех корреляционных функциях определенных операторов, что приводит к неоднозначной перенормировке этих операторов. Показано, что аналогичные резонансы возникают в модели sh-Гордона, которую можно рассматривать и как возмущение свободного безмассового поля, и как возмущение теории Лиувилля. Точный вид резонанса можно установить, используя результат Ал. Замолодчикова. Структура резонансов в теории sin-Гордона осложняется полюсами в вакуумных средних, отвечающих резонансам между самими экспоненциальными операторами, что приводит к более сложным расходимостям для "нуль-векторов".

On combinatorial expansion of the conformal blocks arising from AGT conjecture

4 February 2011 in 11:30

Alexey Litvinov

In my talk I will report on our studying of the origin of combinatorial expansion of the conformal blocks suggested by Alday, Gaiotto and Tachikawa. We consider the algebra A, which is the tensor product of commuting with each other Virasoro and Heisenberg algebras and discover the special orthogonal basis of states in the highest weight representations of A. The matrix elements of primary fields in this basis have a very simple factorized form and coincide with the function called Zbif appearing in the instanton counting literature. Having such a simple basis the problem of computation of the conformal blocks simplifies drastically and can be shown to lead to the expansion proposed by AGT. We found that this basis diagonalizes an infinite system of commuting Integrals of Motion related with some integrable hierarchy

Applying dissipative dynamical systems to pseudorandom number generation: equidistribution property and statistical independence of bits on length up to logarithm of mesh size. RNGSSELIB: Program library for Random Number Generation.

28 January 2011 in 11:30

L.Yu. Barash, L.N. Shchur

The behavior of a family of dissipative dynamical systems representing transformations of two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying dissipative dynamical systems to generation of pseudorandom numbers is shown to be advantageous and equidistribution of probabilities for the sequences of bits can be achieved. New algorithm for generating uniform pseudorandom numbers is proposed. The theory of the generator, including proofs of periodic properties and of statistical independence of bits on length up to logarithm of mesh size, is presented. Extensive statistical testing using available test packages demonstrates excellent results, while the speed of the generator is comparable to other modern generators. The library RNGSSELIB for random number generators (RNGs) based upon the SSE2 command set is presented. The library contains realization of a number of modern and most reliable generators. Usage of SSE2 command set allows to substantially improve performance of the generators. Three new RNG realizations are also constructed. We present detailed analysis of the speed depending on compiler usage and associated optimization level, as well as results of extensive statistical testing for all generators using available test packages. Fast SSE implementations produce exactly the same output sequence as the original algorithms.

Slabo nekogerentnyi predel mezhsloevoi provodimosti v magnitnom pole.

21 January 2011 in 11:30

P.D. Grigor’ev

Issledovan “slabo nekogerentnyi” predel mezhsloevogo perenosa elektronov v magnitnom pole. V sil’no anizotropnykh sloistykh provodnikakh, kogda vremya svobodnogo probega elektronov men’she vremeni ikh mezhsloevogo tunnelirovaniya, standartnaya trekhmernaya teoriya provodimosti v magnitnom pole stanovitsya ne primenimoi. Eto proiskhodit, poskol’ku takaya elektronnaya sistema blizka k dvumernoi, i primesi namnogo sil’nee na nee deistvuyut. Odnako, dazhe ochen’ malyi pereskok elektronov mezhdu sloyami delokalizuet elektronnye sostoyaniya, vyvodit sistemu iz sostoyaniya kvantovogo effekta Kholla i privodit k metallicheskoi mezhsloevoi provodimosti. V rabote predlozhena teoriya magnitnykh kvantovykh ostsillyatsii provodimosti i uglovoi zavisimosti magnitosoprotivleniya v takom slabo nekogerentnom predele [P.D. Grigoriev, «Weakly incoherent magnetotransport in layered metals», arXiv:1010.0926 (2010)]. Provedennyi raschet mezhsloevoi provodimosti vykhodit za ramki traditsionno ispol’zuemogo bornovskogo priblizheniya i uchityvaet polnuyu amplitudu rasseyaniya elektronov na tochechnoi primesi v magnitnom pole v samosoglasovannom priblizhenii. Eto privodit k novym kachestvennym rezul’tatam. Naprimer, poluchen monotonnyi rost mezhsloevogo fonovogo magnitosoprotivleniya s rostom polya vdol’ napravleniya provodimosti. Etot rost poluchen dazhe v minimumakh magnitnykh kvantovykh ostsillyatsii v shirokom diapazone parametrov. Takoi monotonnyi rost nablyudaetsya vo mnogikh eksperimentakh po sloistym metallam i predstavlyaet zagadku uzhe bolee 10 let. Krome etogo, pokazano chto temperatura Dingla rastet proportsional’no kvadratnomu kornyu ot velichiny magnitnogo polya, chto neobkhodimo uchityvat’ pri izvlechenii effektivnoi massy i vremeni rasseyaniya elektronov. Uglovaya zavisimost’ magnitosoprotivleniya v slabo nekogerentnom predele takzhe imeet ryad novykh svoistv. Naprimer, izmenyaetsya amplituda raznykh garmonik v uglovykh ostsillyatsiyakh provodimosti.

Vzaimodeistviya polei vysshikh spinov i teoriya strun

14 January 2011 in 11:30

Dmitrii Polyakov

Postroeny vershinnye operatory, opisyvayushchie vozbuzhdeniya bezmassovykh polei vysshikh spinov v otkrytoi teorii strun. Eti operatory svyazany so skrytymi global’nymi simmetriyami v prostranstve-vremeni. Po postroeniyu, korrelyatsionnye funktsii etikh operatorov na mirovom liste opisyvayut kalibrovochno-invariantnye vzaimodeistviya vysshikh spinov v prostranstve-vremeni, pozvolyaya vychislit’ novye invarianty dlya vzaimodeistvuyushchikh polei vysshikh spinov. Takzhe postroena sigma-model’, opisyvayushchaya stokhasticheskuyu evolyutsiyu polei vysshikh spinov iz ploskogo prostranstva v AdS.

Disordered electron liquid in double quantum well heterostructures: Renormalization group analysis and dephasing rate

17 December 2010 in 11:30

I.S. Burmistrov, I.V. Gornyi (Karlsruhe Institute of Technology), K.S. Tikhonov

V rabote izuchaetsya elektronnyi transport v dvumernoi neuporyadochennoi elektronnoi zhidkosti, sozdannoi v dvoinoi kvantovoi yame, v diffuzionnom rezhime. Naideno, chto dazhe v sluchae odinakovogo primesnogo rasseyaniya v obeikh yamakh, asimmetriya v elektron-elektronnom vzaimodeistvii vnutri i poperek kvantovykh yam privodit k tomu, chto pri nizkikh temperaturakh elektronnaya sistema vedet sebya kak sistema iz dvukh nezavisimykh kvantovykh yam. Provedeno kolichestvennoe sravnenie teorii s eksperimental’nymi dannymi gruppy G.M. Min’kova.

Neravnovesnyi admittans odno-elektronnoi korobki v rezhime cil’noi kulonovskoi blokady

10 December 2010 in 11:30

Ya.I. Rodionov, I.S. Burmistrov

Izucheny admittans i dissipatsiya energii v odno-elektronnoi korobke (malen’kii metallicheskii ostrovok, soedinennyi s rezervuarom tunnel’nym kontaktom; potentsial elektronov na ostrovke kontroliruetsya dopolnitel’nym zatvornym elektrodom) v neravnovesnom rezhime pri prilozhenii peremennogo zatvornogo napryazheniya v rezhime sil’noi kulonovskoi blokady. Vychislen admittans pri ne slishkom nizkoi effektivnoi temperature (energii) elektronov na ostrovke, kogda mozhno prenebrech’ elektronnoi kogerentnost’yu, no neobkhodimo polnost’yu uchityvat’ kvantovye fluktuatsii zaryada iz-za sil’nogo kulonovskogo vzaimodeistviya. Kak okazalos’, dissipatsiya energii mozhet byt’ vyrazhena cherez soprotivlenie zaryadovoi relaksatsii i perenormirovannuyu zaryadovuyu emkost’ dazhe v neravnovesnykh usloviyakh. Povedenie admittansa kak funktsii vneshnei chastoty opredelyaetsya funktsiei raspredeleniya, otvechayushchei bozonnym kollektivnym vozbuzhdeniyam na ostrovke. Poetomu, mozhno ispol’zovat’ admittans odno-elektronnoi korobki dlya izmereniya etoi bozonnoi funktsii raspredeleniya.

Excitation spectrum of a 2D long-range Bose liquid with a supersymmetry

3 December 2010 in 11:30

Mozgunov Evgenii

Polnost’yu opisan spektr vozbuzhdenii spetsial’noi modeli 2D boze-zhidkosti. Eta model’ s sil’nym vzaimodeistviem mozhet byt’ otobrazhena na klassicheskuyu stokhasticheskuyu evolyutsiyu ekvivalentnoi sistemy chastits. Chislenno byla poluchena dinamika zatukhaniya, kotoraya s tochnost’yu do perekhoda v mnimoe vremya sovpadaet s dinamikoi kvantovykh korrelyatsionnykh funktsii. V shirokom diapazone konstant svyazi rotonnyi spektr byl naiden, prichem rotonnaya shchel’ chrezvychaino mala po sravneniyu s kharakternym energeticheskim masshtabom. Edinstvennyi fazovyi perekhod pri nule temperatur v sisteme proiskhodit iz sverkhtekuchego v uporyadochennoe sostoyanie - kristall Berezinskogo.

Anomal’nyi poverkhnostnyi impedans, obuslovlennyi nechyotnoi po chastote sverkhprovodimost’yu

26 November 2010 in 11:30

Y. Asano, A.A. Golubov, Ya.V. Fominov, Y. Tanaka

Rassmotren dinamicheskii otklik nechyotnykh po chastote kuperovskikh par na elektromagnitnoe pole. Vychislen poverkhnostnyi impedans (Z = R - i X) tonkoi plyonki iz normal’nogo metalla, pokryvayushchei tripletnyi sverkhprovodnik. V protivopolozhnost’ obychnomu sootnosheniyu R << X, poverkhnostnyi impedans v spin-tripletnykh sistemakh s effektom blizosti demonstriruet anomal’noe povedenie (t.e. R > X) pri nizkikh temperaturakh. Eto neobychnoe sootnoshenie yavlyaetsya rezul’tatom proniknoveniya v normal’nyi metall nechyotnykh po chastote sverkhprovodyashchikh korrelyatsii i otrazhaet otritsatel’nuyu plotnost’ kuperovskikh par (t.e. protivopolozhnyi obychnomu znak svyazi mezhdu sverkhtokom i vektornym potentsialom).

Sverkhuprugost’ i rasprostranenie udarnykh voln v kristallakh

19 November 2010 in 11:30

N.A. Inogamov, V.V. Zhakhovskii, V.A. Khokhlov, V.V. Shepelev

Rasshcheplenie akusticheskogo vozmushcheniya na uprugii predvestnik i plasticheskuyu volnu otnositsya k chislu vazhneishikh yavlenii v fizike udarnykh voln v tverdykh sredakh. V predlagaemoi rabote razrabotana fizicheskaya model’ i matematicheskaya metodika obrabotki nablyudenii udarno-volnovykh yavlenii v metallakh, obluchennykh femtosekundnym lazernym impul’som. Ispol’zovanie eksperimental’nykh rezul’tatov sovmestno s molekulyarno-dinamicheskim modelirovaniem i dvukhtemperaturnymi gidrodinamicheskimi raschetami dalo vozmozhnost’ issledovat’ uprugie svoistva kristallov alyuminiya i nikelya pri ekstremal’nykh znacheniyakh sdvigovykh napryazhenii, sravnimykh po amplitude s modulem sdviga. Eto pozvolilo prodlit’ upruguyu adiabatu Gyugonio v oblast’ metastabil’nykh elasticheskikh sostoyanii pri chrezvychaino vysokikh davleniyakh, na 1-2 poryadka prevyshayushchikh obychno prinimaemye znacheniya dlya dinamicheskogo predela uprugosti. Pokazano, chto ul’trakorotkaya uprugaya udarnaya volna sverkhvysokogo davleniya predshestvuet formirovaniyu izvestnoi dvukhvolnovoi struktury iz uprugogo predvestnika i plasticheskoi udarnoi volny.

Kvantovaya spinovaya zhidkost’ so stepennym povedeniem korrelyatorov vblizi tochno reshaemoi tochki

12 November 2010 in 11:30

K. Tikhonov, M. Feigel’man i A. Kitaev

Issledovana slabo vozmushchennaya model’ spinovoi reshetki sot s anizotropnym parnym vzaimodeistviem. Tochno reshaemaya model’, predlozhennaya i issledovannaya A. Kitaevym ranee, privodit k lokal’nym spinovym korrelyatoram. My pokazali, chto vvedenie v etu model’ slabogo vozmushcheniya, narushayushchego tochnuyu integriruemost’, privodit k poyavleniyu stepennoi asimptotiki dinamicheskikh spinovykh korrelyatorov. Tem samym pred’yavlen primer “kriticheskoi” kvantovoi spinovoi zhidkosti.

Three approaches to the 2d Quantum gravity

29 October 2010 in 11:30

A. Belavin, M. Bershtein, G. Tarnopolsky

The one-matrix model in the $p$-critical point is considered. We found an explicit expression for the genus 2 free energy. Also we discuss its relation to the Topological gravity. We explain that the free energy of the $p$-critical Matrix model is an analytic continuation of the generating function of the Topological gravity. We check the topological recursion relations for correlation functions in the $p$-critical Matrix model.

Sverkhmassivnaya chernaya dyra v ellipticheskoi galaktike: akkretsiya goryachego gaza s malym, no konechnym uglovym momentom

22 October 2010 in 11:30

N.A. Inogamov, R.A. Syunyaev

Рассмотрена аккреция на сверхмассивную черную дыру горячего медленно вращающегося газа. В работе изучен важный случай, когда на радиусе Бонди $r_B$ скорости турбулентных пульсаций малы по сравнению со скоростью звука $c_s.$ По-видимому, турбулентность ответственна за появление случайного среднего вращения. Несмотря на то, что на размере $r_B$ вращательный момент невелик, с ним связано формирование на глубине $r_c=l^2/G M_{BH}\ll r_B$ центробежного барьера, препятствующего сверхзвуковой аккреции. В статье найдено численное решение задачи аккреции горячего газа с конечным угловым моментом с учетом электронной теплопроводности и потерь энергии двухтемпературной плазмой на тормозное излучение. Учитывалось насыщение спитцеровской теплопроводности. Параметры насыщенной электронной теплопроводности выбирались в соответствии с принятыми в расчетных работах по исследованию воздействия сильных лазерных пучков на плазменные мишени и подтвержденными в экспериментах. Показано, что совместное действие электронной теплопроводности и тормозного излучения ведет к эффективному охлажению аккрецирующей плазмы и формированию режима дозвукового оседания аккрецирующего вещества над зоной центробежного барьера. Вблизи барьера возникает тороидальное уплотнение и полая воронка, отделяющая тор от черной дыры. Барьер делит течение на две области — 1) зону оседания с {\it медленным} дозвуковым вращением и 2) зону с {\it быстрым} сверхзвуковым околокеплеровским вращением. Первую зону будем называть атмосферой над тором. Наличие центробежного барьера приводит к сильному снижению темпа аккреции $\dot M$ по сравнению с критическим решением Бонди для $\gamma=5/3$ для тех же значений плотности и температуры горячей плазмы вблизи радиуса Бонди. Сдвиговые неустойчивости в торе и связанное с ними трение приводят к медленному растеканию газа в экваториальной плоскости в двух направлениях. В результате образуются внешний $r>r_c$ и внутренний $r

Collapse as a process of pulse shortening

15 October 2010 in 11:30

E.A. Kuznetsov

In this talk we discuss a possibility of light pulse compression in fiber optics using the mechanism of wave collapse. It is well known that wave collapse in optics provides the giant pulse shortening in two- and three-dimensional geometry due to the Kerr nonlinearity. However, in the one-dimensional case, for instance, in fibers the cubic Kerr nonlinearity is compensated by wave dispersion responsible for the optical pulse broadening that results in stable optical envelope solitons. By this reason, the wave collapse in such a case is impossible. We consider two mechanisms how it is possible to diminish the Kerr constant in order to provide wave collapse appearance due to higher nonlinearities. The first mechanism weaken the Kerr constant is connected with the interaction of light and acoustic waves (or Mandelshtam-Brillouin scattering) Another idea was suggested by Gabitov and Lushnikov to use a nonlinear phase-shift interferometric converter (the analog of the MachZehnder interferometer) which provides a way to control the sign of the nonlinear phase shift. In the case of a small Kerr constant it is necessary to take into account the higher nonlinearities: nonlinear correction to the group velocity, responsible for pulse steepening, Raman scattering and six-wave interaction as well. In thissituation depending on the sign of the renormalized Kerr constant  there exist two soliton families. For the first family with positive  for very small amplitudes these solitons are nothing more than the NLS solitons of the sech form. For larger amplitudes these solitons transform into pulses with a chirp and an almost constant pulse energy. This soliton family is shown to be stable in the Lyapunov sense. The second soliton family with  < 0 has the same behavior at small pulse durations but occurs to be unstable. The nonlinear development of this instability results in the collapse of solitons. Near the collapse time, the pulse amplitude and its width exhibit a self-similar behavior with a small asymmetry in the pulse tails due to self-steepening.

Anomal’nye dinamicheskie svoistva magnetikov pri nizkikh temperaturakh

1 October 2010 in 11:30

Arsenii Syromyatnikov, PIYaF

Teoreticheski rassmatrivaetsya ryad magnitnykh sistem, imeyushchikh neobychnye dinamicheskie svoistva pri nizkikh temperaturakh. V chastnosti obnaruzheno anomal’no sil’noe zatukhanie dlinnovolnovykh magnonov, sravnimoe s ikh energiei, v ferromagnetikakh s dipol’nymi silami pri T ≪ Tc. Vychislena dinamicheskaya vospriimchivost’ vyrozhdennoi primesi v kvazi-2D antiferromagnetike (AF) pri T ≪ TN i issledovano vliyanie konechnoi kontsentratsii n takikh primesei na svoistva AF. Obnaruzheno sil’noe zatukhanie dlinnovolnovykh magnonov proportsional’noe ikh energii i n. Naiden spektr korotkovolnovykh magnonov v 2D AF v sil’nom magnitnom pole H pri T=0 v glavnom poryadke po malomu parametru (Hc-H)/Hc, gde Hc – pole nasyshcheniya. Vychislen spektr magnonov v 2D AF Geizenberga pri T=0 v tret’em poryadke po 1/S.

Compact model for water waves

24 September 2010 in 11:30

A.I. D’yachenko

Simple equation describing evolution of "almost" 1-D water waves is derived. This new hamiltonian equation is based on the important property of vanishing four-wave interaction for water waves discovered in 1994. This remarkable property allows to simplify Zakharov equation significantly. Now it does not contain multiple integrations in Fourier space and is written in coordinate space. For 2-D surface waves it can be generalized in the spirit of Kadomtsev-Petviashvili equation for Korteveg-de-Vries equation. It is applicable for much more steeper wave then the nonlinear Shredinger equation or the Dysthe equation.

BEC of non-equilibrium quasiparticles in 3He and beyond

17 September 2010 in 11:30

Grigory Volovik

Bose-Einstein condensation (BEC) of excitations (or quasiparticles) whose number is not conserved is presently one of the debated phenomena of condensed matter physics. In thermal equilibrium the chemical potential of excitations or non-conserved particles (phonons, excitons, polaritons, magnons, photons, ripplons, etc.) vanishes and, as a result, their condensate cannot not form as an equilibrium state. BEC of excitations may exist only as a dynamic non-equilibrium phenomenon, when the condensate is either decaying with time, or persists as a steady state in which the decay of excitations/particles is compensated by continuous pumping of new excitations/particles. For magnetic excitations - magnons -the dynamic BEC is manifested as the spontaneous phase-coherent precession of spins. The magnon BEC was first discovered in 1984 in superfluid 3He-B and later observed in other systems. Magnon BEC is accompanied by superfluidity of magnons, and since each magnon carries spin sz = -1, this is spin superfluidity. We discuss different phases of magnon BEC (including those formed in magnetic-textural traps), the observed signatures of spin superfluidity: (i) spin supercurrent, which transports the magnetization over a macroscopic distance more than 1 cm long; (ii) spin current Josephson effect which shows interference between two condensates; (iii) spin current vortex — a topological defect which is an analog of a quantized vortex in superfluids and an Abrikosov vortex in superconductors; (iv) Goldstone modes related to the broken U(1) symmetry, which are analogous to sound waves in atomic BEC; etc., and specific properties of BEC of excitations which have no analogs in atomic BEC, such as parametric instability of magnon BEC and mass of the Goldstone mode.

Charge solitons and their dynamical mass in 1-D arrays of Josephson junctions

10 September 2010 in 11:30

Ivan Protopopov

We investigate the charge transport in one-dimensional arrays of Josephson junctions. In the interesting regime of “small charge solitons” (polarons), the charge dynamics is strongly influenced by the polaronic effects, i.e., by dressing of a Cooper pair by charge dipoles. In particular, the soliton's mass in this regime scales approximately as inverse square of the Josephson energy. We employ two theoretical techniques: the many body tight-binding approach and the mean-field approach. Results of the two approaches agree in the regime of “small charge solitons”.

Critical amplitude ratios of the Baxter-Wu model

3 September 2010 in 11:30

L. Shchur, W. Janke

A Monte Carlo simulation study of the critical and off-critical behavior of the Baxter-Wu model, which belongs to the universality class of the 4-state Potts model, was performed. We estimate the critical temperature window using known analytical results for the specific heat and magnetization. This helps us to extract reliable values of universal combinations of critical amplitudes with reasonable accuracy. Comparisons with approximate analytical predictions and other numerical results are discussed.

Effekty chetnosti v SNS-kontakte na poverkhnosti topologicheskogo izolyatora

18 June 2010 in 11:30

Pavel Ioselevich

V kore vikhrya na sverkhprovodyashchei poverkhnosti topologicheskogo izolyatora sushchestvuet lokalizovannoe maioranovskoe sostoyanie (MBS). Izuchaetsya Dzhozefsonovskii kontur, v kotorom para takikh MBS lokalizovana v oblasti SNS-kontakta. MBS privodit k tomu, chto pri adiabaticheskom izmenenii fazy kontakta φ → φ + 2π fermionnaya chyotnost’ osnovnogo sostoyaniya sistemy menyaetsya. Blagodarya etomu energiya i tok sistemy 4π-periodicheskie po faze. 4π-periodicheskaya chast’ toka poryadka 2eΔ/ħ pri nule temperatur i eksponentsial’no podavlyaetsya pri temperature vyshe nekotoroi kriticheskoi.

Two dimensional gravity in genus one in Matrix Models etc.

18 June 2010 in 11:30

G. Tarnopolsky

One-matrix model in p-critical point on torus is considered. The generating function of correlation numbers in genus one is evaluated and used for computation correlation numbers in KdV and CFT frames. It is shown that the correlation numbers in KdV frame in genus one satisfy the Witten topological gravity recurrence relations.

Integriruemye ODU s neskol’kimi matrichnymi neizvestnymi

11 June 2010 in 11:30

V.V. Sokolov

Rassmatrivayutsya tochno integriruemye nelineinye differentsial’nye uravneniya s matrichnymi neizvestnymi. Osnovnye ponyatiya, takie kak simmetrii, pervye integraly, gamil’tonovy struktury, obobshchayutsya na etot sluchai. Rassmatrivaetsya zadacha opisaniya lineinykh i kvadratichnykh skobok Puassona, sootvetstvuyushchikh takim modelyam. Privodyatsya primery.

Nucleation processes and their study by simulations

4 June 2010 in 11:30

Kurt Binder (Institut fuer Physik, Johannes-Gutenberg Universitaet, Mainz, Germany)

Nucleation of liquid droplets from metastable vapor is an old problem, but the conditions for which the “classical theory” of nucleation holds are still controversial. The difficulty is that the critical nuclei that trigger the phase transformation are rather rare objects of nanoscopic size, their direct observation is almost impossible, and the use of macroscopic concepts is doubtful. While many of these difficulties also hamper simulations, new concepts to analyze simulations have made it possible to “measure” nucleation barriers over many orders of magnitude for various models. Also an extension to analyze the basic ideas about heterogeneous nucleation of wall-attached droplets has become possible. By these techniques controversial topics (significance of a Tolman length, role of line tension) can be clarified. But important questions about nucleation kinetics still remain an open problem.

Formula lokalizatsii i instantonnye vychisleniya

28 May 2010 in 11:30

M.A. Bershtein

Formula lokalizatsii pozvolyaet svodit’ vychislenie integralov k vychisleniyu vkladov osobykh tochek. Mozhno skazat’, chto ona daet usloviya pri kotorykh metod perevala daet tochnyi otvet (kvaziklassika tochna). V doklade budet rasskazana sama teorema i privedeny nekotorye primery, v chastnosti vychislenie integrala Itsiksona-Zyubera i Nekrasovskoe vychislenie integrala po prostranstvu modulei instantonov v N=2 SUSY teorii Yanga-Millsa.

Usilenie elektricheskogo polya mezhdu metallicheskimi granulami vsledstvie plazmonnogo rezonansa

21 May 2010 in 11:30

P.E. Vorob’ev

Rassmatrivaetsya vzaimodeistvie pary metallicheskikh granul, pogruzhennykh v dielektrik, s elektromagnitnoi volnoi. Predpolagaetsya, chto dlina padayushchei volny mnogo bol’she, chem razmer granul. Issleduyutsya usloviya plazmonnogo rezonansa v takoi sisteme i koeffitsient usileniya elektricheskogo polya volny v uzkom zazore mezhdu granulami v usloviyakh rezonansa. Okazyvaetsya, chto usloviya rezonansa opredelyayutsya, v osnovnom, geometriei zazora, togda kak usilenie polya zavisit ot geometrii vsei sistemy. Rassmatrivaetsya usilenie polya mezhdu granulami razlichnykh form.

Lokal’noe usilenie elektromagnitnogo signala pri peredache informatsii po optovoloknu v rezhime sil’nogo perekrytiya bitovykh impul’sov.

7 May 2010 in 11:30

Vergeles S.S., Turitsyn S.K.

Rassmotren lineinyi rezhim peredachi informatsii po optovoloknu. Predpolagaetsya, chto v silu bol’shoi plotnosti peredachi informatsii impul’sy, peredayushchie otdel’nyi bit informatsii, dostatochno uzki v chastotnom predstavlenii. Eto privodit k sil’noi roli dispersii. Rassmatrivaetsya skhema translyatsii po optovoloknu, pri kotoroi impul’sy v protsesse rasprostraneniya po nemu rasplyvayutsya vsledstvie dispersii nastol’ko, chto v kazhdoi tochke perekryvaetsya bol’shoe chislo impul’sov. My issleduem statistiku etogo perekrytiya i pokazyvaem, chto v silu sluchainosti peredavaemoi posledovatel’nosti bitov ogibayushchaya elektricheskogo polya imeet lokal’nye maksimumy, amplituda kotorykh mnogo bol’she nachal’noi amplitudy otdel’nykh impul’sov. My issleduem statisticheskie parametry etikh pikov. Poluchena avtomodel’naya zavisimost’ funktsii raspredeleniya moshchnosti vybrosov v zavisimosti ot nachal’nykh parametrov otdel’nykh impul’sov.

Dephasing at the integer quantum Hall transitions: short-ranged interaction in the singlet channel

30 April 2010 in 11:30

I.S. Burmistrov

Temperaturnaya zavisimost’ provodimosti na perekhode mezhdu plato v rezhime tselochislennogo kvantovogo effekta Kholla opredelyaetsya kriticheskim indeksom κ, kotoryi est’ otnoshenie indeksa korrelyatsionnoi dliny (ν) i indeksa dliny razfazirovki (p), κ = p/(2ν). V otlichie ot indeksa korrelyatsionnoi dliny, kotoryi mnogo raz vychislyalsya, indeks p izuchalsya teoreticheski i chislenno tol’ko v neskol’kikh rabotakh. V etikh rabotakh indeks p dliny razfazirovki byl vychislen v predpolozhenii, chto on opredelyaetsya anomal’noi razmernost’yu irrelevantnogo operatora, vkhodyashchego v «inverse participation ratio». V rabote analiticheski pokazyvaetsya, chto dlya sluchaya ekranirovannogo kulonovskogo vzaimodeistviya v singletnom kanale eto predpolozhenie deistvitel’no vypolnyaetsya dlya Andersonovskogo perekhoda v unitarnom klasse (magnitnoe pole) v razmernosti 2 + ε. Provedennye chislennye raschety ukazyvayut na to, chto eto predpolozhenie vypolnyaetsya i dlya perekhoda mezhdu plato.

Dinamika relaksatsii elektronov v zadache o kulonovskoi blokade

23 April 2010 in 11:30

Ya.I. Rodionov

My issleduem relaksatsionnuyu dinamiku elektronov v odnoelektronnom tranzistore. Imenno, my otvechaem na sleduyushchii vopros. Predpolozhim, chto neravnovesnoe elektronnoe raspredelenie obrazovalos’ v protsesse eksperimenta. Po kakomu zakonu ono budet relaksirovat’ k ravnovesiyu? Issledovanie relaksatsii provedeno v rezhimakh slaboi i sil’noi kulonovskoi blokady. Vyvedeny i resheny osnovnye kvantovye kineticheskie uravneniya, upravlyayushchie dinamikoi funktsii raspredeleniya v protsesse ustanovleniya teplovogo ravnovesiya. Ustanovleny universal’nye formuly dlya transportnykh koeffitsientov, prigodnye dlya tranzistora s tunnel’noi svyaz’yu lyuboi prozrachnosti. Krome togo, osushchestvlena odnopetlevaya perenormirovka osnovnykh fizicheskikh velichin, opredelyayushchikh transportnye nablyudaemye, chto pozvolyaet nam poluchit’ naibolee tochnye rezul’taty.

Vliyanie vzaimodeistviya na topologicheskuyu klassifikatsiyu svobodnykh fermionov

16 April 2010 in 11:30

Aleksei Kitaev (Caltech)


Hydrodynamics of Bubble Chains

9 April 2010 in 11:30

A.V. Byalko

A solution of hydrodynamic equations is obtained for the case of laminar bubble chain. Bubble sizes along the chain can either change both ways due to gas-liquid interactions or grow due to pressure decrease. The liquid velocity in regions near chains occurs to be independent on viscosity, so this solution can be applied approximately to the turbulent bubble flow. In some diapason of initial sizes and frequencies the same bubble chain can be either finite or reach the surface.

Non-equilibrium “functional” Bozonization and electron transport in quantum interferometers

2 April 2010 in 11:30

Dmitry Bagrets (INT, Karlsruhe Institute of Technology, Germany)

In this talk I would like to give the details of the theoretical approach which is briefly mentioned in my first lecture. I will discuss a physical model which enable to calculate the non-equilibrium current and, generally, the full current statistics in the quantum electronic interferometers in the presence of Coulomb interaction. The model is based on a (“functionally”) bosonized Keldysh action of interacting electrons, expressed in terms of single-particle time-dependent interferometer’s scattering matrix. I will use this action to analyze the limit of weak electron tunneling between interferometer’s arms in case of arbitrary strong e-e interaction. In particular, a real-time instanton approach to evaluate the non-equilibrium dephasing rates, suppressing the Aharanov-Bohm oscillations of conductance with the increase of voltage, will be discussed. It gives a dephasing rate proportional to the shot-noise power of the quantum point contacts (QPC’s) which define the interferometer and originates from the emission of non-equilibrium plasmons in course of inelastic electron tunneling. The results of this simple model nicely explain the unusual non-monotonic dependence of visibility observed in many recent experiments.

Fraktal’naya sverkhprovodimost’ i perekhod sverkhprovodnik-izolyator (chast’ 3)

26 March 2010 in 11:30

M.V. Feigel’man

Uglovaya zavisimost’ magnitosoprotivleniya kak sposob opredeleniya zakona dispersii v kvazidvumernykh metallakh

19 March 2010 in 11:30

P.D. Grigor’ev

Provedeno issledovanie uglovoi zavisimosti magnitosoprotivleniya v kvazidvumernykh metallakh. Etot effekt traditsionno ispol’zuetsya dlya opredeleniya zakona dispersii elektronov v metalle i geometrii poverkhnosti Fermi. V poslednee vremya etot effekt uspeshno konkuriruet s ARPES dlya polucheniya dannykh ob elektronnoi strukture vysokotemperaturnykh sverkhprovodnikov. V rabote polucheny analiticheskie formuly dlya uglovoi zavisimosti magnitosoprotivleniya, udobnye dlya izvlecheniya parametrov elektronnoi dispersii iz eksperimental’nykh dannykh, i provedeno sopostavlenie s eksperimentom. Issledovana oblast’ primenimosti poluchennykh i bolee rannikh rezul’tatov. Provedeny chislennye raschety uglovoi zavisimosti magnitosoprotivleniya dlya parametrov, sootvetstvuyushchikh sloistym vysokotemperaturnym sverkhprovodnikam.

Modifikatsiya tochno reshaemoi modeli Kitaeva (spin 1/2) na dekorirovannoi shestiugol’noi reshetke s osnovnym sostoyaniem tipa «spinovyi metall»

12 March 2010 in 11:30

K.S. Tikhonov

Гамильтониан диагонализуется в представлении Майорановских фермионов, которые образуют 2D бесщелевое состояние с Ферми-окружностью, диаметр которой определяется соотношением констант связи. Вычислена теплоемкость и динамическая спиновая восприимчивость, которая имеет степенной пик вблизи резонансной частоты. Определена соответствующая экспонента и форма пика.

Sverkhprovodyashchii tripletnyi spinovyi klapan

5 March 2010 in 11:30

Ya. Fominov, A. Golubov, T. Karminskaya, M. Kupriyanov, R. Deminov, L. Tagirov

Issleduetsya kriticheskaya temperatura Tc tryokhsloinoi SFF struktury (S — obychnyi singletnyi sverkhprovodnik, F — ferromagnitnyi metall), v kotoroi pri nekollinearnykh namagnichennostyakh F sloyov voznikaet dal’nodeistvuyushchaya tripletnaya sverkhprovodyashchaya komponenta. Pokazano, chto Tc mozhet byt’ nemonotonnoi funktsiei ugla α mezhdu namagnichennostyami dvukh F sloyov. Minimum dostigaetsya pri promezhutochnom znachenii α, lezhashchim mezhdu parallel’nym (P, α = 0) i antiparallel’nym (AP, α = π) sluchayami. Eto oznachaet vozmozhnost’ «tripletnogo» effekta spinovogo klapana: pri temperaturakh vyshe minimuma TcTr, no nizhe TcPTcAP, sistema budet v sverkhprovodyashchem sostoyanii tol’ko pri orientatsiyakh, blizkikh k kollinearnym. Pri opredelyonnykh parametrakh zavisimost’ Tc(α) budet imet’ vozvratnyi kharakter. Esli zhe rassmatrivat’ tol’ko P i AP konfiguratsii, to okazyvaetsya , chto v zavisimosti ot parametrov sistemy vozmozhen kak «standartnyi» (TcP < TcAP), tak i «obratnyi» (TcP > TcAP) effekt pereklyucheniya.

Charging states in Andreev quantum dot

26 February 2010 in 11:30

I.A. Sadovsky

V rabote izuchaetsya zaryad v kvantovoi tochke, prisoedinennoi k sverkhprovodyashchim beregam. Podstraivaya potentsial zatvora i raznitsu sverkhprovodyashchikh faz mezhdu sverkhprovodnikami mozhno nepreryvno izmenyat’ zaryad (v predelakh odnogo zaryada kuperovskoi pary na odin kanal). Issledovany effekty kulonovskogo i elektron-fononnogo vzaimodeistviya v predele beskonechnoi sverkhprovodyashchei shcheli.

Topological transition in a non-Hermitian quantum walk

19 February 2010 in 11:30

L. Levitov (MIT)

We analyze a quantum walk on a bipartite one-dimensional lattice, in which the particle can decay whenever it visits one of the two sublattices. The corresponding non-Hermitian tight-binding problem with complex potential for the decaying sites exhibits two distinct phases, distinguished by a winding number defined in terms of the Bloch eigenstates in the Brillouin zone [M.S. Rudner, L.S. Levitov, Phys. Rev. Lett. 102, 065703 (2009)]. We find that the mean displacement of a particle initially localized on one of the non-decaying sites is quantized as an integer, changing from zero to one at the critical point. By mapping this problem onto a Jaynes-Cummings-type model with decay, we find that the topological transition is relevant for a variety of experimental settings, in particular for superconducting qubits coupled to high quality resonators [A. Wallraff et al., Nature 431, 162-167 (2004)]. The quantized behavior stands in contrast with the smooth dependence expected for a classical random walk, and can serve as a hallmark of coherent quantum dynamics in ladder-like multilevel systems. A real-space implementation of the quantum walk may help to verify quantum coherence in vortex transport in Josephson arrays [A. van Oudenaarden, S.J.K. Vardy, and J. E. Mooij, Phys. Rev. Lett. 77, 4257 (1996)].

Thermodynamic magnetization of a strongly interacting two-dimensional system

12 February 2010 in 11:30

M. Reznikov (Tekhnion, Khaifa)

We report thermodynamic magnetization measurements of a 2-dimensional electron gas for several high mobility Si-MOSFETs. The low-temperature magnetization is shown to be strongly sub-linear function of the magnetic field. The susceptibility determined from the zero-field slope diverges as Tα, with α = 2.2–2.6 even at high electron densities, in apparent contradiction with the Fermi-liquid picture.

Superconducting textures in two dimensions

5 February 2010 in 11:30

N.M. Shchelkachev

Instanton v pryamom kaskade dvumernoi turbulentnosti

29 January 2010 in 11:30

V.V. Lebedev

Passive scalar transport in peripheral regions of random flows

22 January 2010 in 11:30

A. Chernykh, V. Lebedev

We investigate statistical properties of the passive scalar near boundaries (walls) in random (turbulent) flows assuming weakness of its diffusion. Then at advanced stages of the passive scalar mixing its unmixed residue is concentrated in a narrow diffusive layer near the wall and its transport to bulk goes through the peripheral region (laminar sublayer). We conducted Lagrangian numerical simulations of the process for different space dimensions d and revealed structures responsible for the transport that are passive scalar tongues pulled from the diffusive boundary layer to bulk. We investigated statistical properties of the passive scalar and of the passive scalar integrated along the wall. Moments of both objects demonstrate scaling behavior outside the diffusive boundary layer. We propose an analytical scheme for explanation scaling of the passive scalar, the obtained exponents agree reasonably with numerics in 3d.

Fraktal’naya sverkhprovodimost’ i perekhod sverkhprovodnik-izolyator (chast’ 2)

15 January 2010 in 11:30

M.V. Feigel’man

Zasedanie Dissertatsionnogo soveta ITF

25 December 2009 in 11:30

  • Zashchita kandidatskoi dissertatsii Barasha L.Yu. «Isparenie i dinamika lezhashchei na podlozhke kapli».
  • Zashchita kandidatskoi dissertatsii Lyubshina D.S. «Odnoklasternye perkolyatsionnye sistemy i modeli granulirovannykh metallov».

Formalism of Ghost Cohomologies in String Theory

18 December 2009 in 11:30

Dimitri Polyakov (University of the Witwatersrand, Johannesburg)

I review the basic results of the ghost cohomology approach in string theory that I have developed over the recent years. This includes new global space-time symmetries in string theory (alpha-symmetries), observed in this approach and related to hidden space-time dimensions, as well as new results in the problem of gauge-string correspondence and in gauge theories of interacting higher spin fields.

Fraktal’naya sverkhprovodimost’ i perekhod sverkhprovodnik-izolyator (chast’ 1)

11 December 2009 in 11:30

M.V. Feigel’man

Volny-ubiitsy i vetrovoe volnenie

4 December 2009 in 11:30

Zakharov V.E.

Diffuzionnyi perekhod otritsatel’nykh ionov cherez granitsu kriogennykh zhidkostei

27 November 2009 in 11:30

P.D. Grigor’ev, A.M. Dyugaev, E.V. Lebedeva

Vpervye ob’yasneno neobychno maloe vremya zhizni otritsatel’nykh ionov (elektronnykh puzyr’kov) vblizi poverkhnosti zhidkosti i postroena kolichestvennaya teoriya zavisimosti etogo vremeni zhizni ot temperatury i vneshnego elektricheskogo polya. Pri opredelenii potentsial vzaimodeistviya takikh otritsatel’nykh ionov s poverkhnost’yu zhidkostei (naprimer, zhidkikh He4, He3 i Ne), krome elektrostaticheskogo ottalkivaniya uchten vklad dal’nodeistvuyushchego van-der-vaal’sovskogo prityazheniya elektronnogo puzyr’ka k poverkhnosti zhidkosti. Potentsial’nyi bar’er, prepyatstvuyushchii ukhodu otritsatel’nogo iona iz zhidkosti v vakuum, formiruetsya v rezul’tate konkurentsii etikh sil ottalkivaniya i prityazheniya. Opredelena zavisimost’ vremeni zhizni puzyr’ka ot temperatury i elektricheskogo polya dlya neskol’kikh zhidkostei. Provedeno sravnenie teorii i opyta dlya otritsatel’nykh ionov v zhidkom He4. V otlichie ot obshcheprinyatykh predstavlenii, osnovannykh na gipoteze kvantovogo tunnelirovaniya elektrona iz puzyr’ka v vakuum, obosnovannaya nami teoriya baziruetsya na klassicheskoi diffuzionnoi modeli perekhoda puzyr’ka cherez potentsial’nyi bar’er, predlozhennoi Kramersom. Dlya zhidkogo He4 v ramkakh etoi modeli primenimo priblizhenie malogo dinamicheskogo treniya, chto svyazano s bol’shoi podvizhnost’yu otritsatel’nykh ionov v sverkhtekuchei zhidkosti. Rezul’taty issledovaniya mogut naiti primenenie dlya opisaniya kinetiki otritsatel’nykh ionov vblizi poverkhnostei razlichnykh zhidkostei. Postroena takzhe teoriya perekhoda elektronnykh puzyotkov cherez granitsu razdela kriogennykh zhidkostei, osnovannaya na novom podkhode k vychisleniyu potentsiala vzaimodeistviya puzyr’ka s granitsei. Podtverzhdeniem teorii sluzhit khoroshee sootvetstvie s esperimentami po izmereniyu zavisimosti ot vneshnego elektricheskogo polya potentsial’nogo bar’era na granitse He3, He4 vakuuma, a takzhe na granitse nasyshchennykh rastvorov He3 i He4. Vyyavlena izotopicheskaya invariantnost’ zavisimosti potentsiala vzaimodeistviya ot rasstoyaniya mezhdu elektronnym puzyr’kom i granitsei razdela po otnosheniyu k trem variantam takoi granitsy. Dlya otritsatel’nykh ionov v He3 i He4 opredelena zavisimost’ ikh vremeni zhizni ot temperatury i elektricheskogo polya, osnovannaya na teorii Kramersa.

Short pulse nanostructuring by lasers with different wavelengths

20 November 2009 in 11:30

S.I. Anisimov, N.A. Inogamov, Yu.V. Petrov, V.A. Khokhlov, V.V. Zhakhovskii, M.B. Agranat, S.I. Ashitkov, A.Ya. Faenov, I.Yu. Skobelev, V.V. Shepelev

Short laser pulse with any wavelength from infrared to X-ray disturbs electron-ion equilibrium and rises pressure in a heated layer. In the report the case when pulse duration τL is shorter than acoustic relaxation time ts is considered. Such pulse is a reason of thermomechanical phenomena and spallative ablation irrespectively of wavelength. While, of course, physics of electron-ion relaxation strongly depends on wavelength and the electron spectra of substances - there are spectra with an energy gap Δ (semiconductors, dielectrics) versus continuous spectra (metals). The report describes the whole set of the thermomechanical processes as expansion-nucleation-foaming-nanostructuring-spallation with particular attention to spallation by X-ray pulse.

Korrelyatsii lokal’nykh plotnostei sostoyanii v kvaziodnomernoi provoloke

13 November 2009 in 11:30

M.A. Skvortsov

Vychislena korrelyatsionnaya funktsiya lokal’nykh plotnostei sostoyanii na malen’koi raznosti energii v neuporyadochennoi kvaziodnomernoi provoloke unitarnogo klassa simmetrii. S pomoshch’yu supersimmetrichnoi sigma-modeli naidena polnaya zavisimost’ dvukhtochechnoi korrelyatsionnoi funktsii ot rasstoyaniya mezhdu tochkami. V predele nulevoi raznosti energii vosproizvedena statistika odnoi volnovoi funktsii. Na logarifmicheski bol’shikh rasstoyaniyakh poryadka mottovskogo masshtaba poluchena nemonotonnaya zavisimost’, soglasuyushchayasya s rezul’tatami dlya strogo odnomernogo sluchaya.

Sinkhrotronnoe izluchenie glyuonov

6 November 2009 in 11:30

B.G. Zakharov

Possible solution of cosmological constant problem: Minkowski vacuum as attractor

30 October 2009 in 11:30

G.E. Volovik

The q-theory of quantum vacuum is extended to the vector vacuum field. It is demonstrated that the Minkowski vacuum with vanishing cosmological constant is the attractor of dynamical equations, which means that cosmological constant relaxes to zero without fine-tuning.

O gipoteze Aldi, Gaioto i Tachikavy (Aldy, Gaiotto, and Tachikawa)

30 October 2009 in 11:30

A.A. Belavin

Eta gipoteza zaklyuchaetsya v predpolozhenii o sootvetstvii mezhdu 4-mernymi Superkonformnymi Neabelevymi Kalibrovochnymi teoriyami, s odnoi storony, i 2-mernymi Konformnymi teoriyami, s drugoi. V chastnosti, statsumma SU(2) kalibrovochnoi teoriii s chislom gipermul’tipletov, ravnym 4, sovpadaet s 4-kh tochechnoi korrelyatsionnoi funktsiei v Teorii Liuvillya.

Vortex structures in rotating Bose-Einstein condensates

16 October 2009 in 11:30

S.I. Matveenko

We present an analytical solution for the vortex lattice in a rapidly rotating trapped Bose-Einstein condensate in the lowest Landau level and discuss deviations from the Thomas-Fermi density profile. This solution is exact in the limit of a large number of vortices and is obtained for the cases of circularly symmetric and narrow channel geometries. For the latter case we calculate the phase diagram as a function of the interaction strength and rotation frequency and identify the order of quantum phase transitions between the states with a different number of vortex rows.

Role of thermal fluctuations in vesicle dynamics in an external shear flow

9 October 2009 in 11:30

S.S. Vergeles, V.V. Lebedev, K.S. Turitsyn

We examine an influence of thermal fluctuations on the phase diagram for vesicle dynamics in an external shear flow where different regimes are observed: tumbling, tank-treading, trembling. We demonstrate that thermal fluctuations extend the region of existence of trembling. The effect enables us to explain recent experimental data.

Superfluid 3He-B as topological insulator

2 October 2009 in 11:30

G. Volovik

We consider topological invariant describing the vacuum states of superfluid 3He-B, which belongs to the special class of time-reversal invariant topological insulators and superfluids. Integer valued topological invariant is expressed in terms of the Green's function, which allows us to consider systems with interaction. Discrete symmetries important for classification of the topologically distinct vacuum states are discussed. One of them leads to the additional subclasses of 3He-B states and is responsible for the finite density of states of Majorana fermions living on the diffusive wall.

Rasshirennoe zasedanie Uchenogo soveta ITF, posvyashchennoe yubileyu S.V. Iordanskogo

25 September 2009 in 11:30

G.E. Volovik, A.M. Finkel’shtein, S.E. Korshunov, E.A. Brener

11:30-12:15 G.E. Volovik, «Sila Iordanskogo i kvantovaya turbulentnost’».
12:15-13:00 A.M. Finkel’shtein, «Effektivnaya teoriya rasprostraneniya impul’sov v nelineinykh i neuporyadochennykh sredakh».
13:15-14:00 S.E. Korshunov, «Fazovye perekhody v dvumernykh reshetkakh SFS kontaktov».
14:00-14:45 E.A. Brener, «Asimpototicheskie nelineinosti v smektikakh».

O vozmozhnoi klimaticheskoi neustoichivosti

11 September 2009 in 11:30

A.V. Byalko, N.I. Vaganova, E.N. Rumanov (Institut strukturnoi makrokinetiki i problem materialovedeniya RAN)

Kvantovyi transport v grafene: interferentsiya v pnp-kontaktakh, lokalizatsiya na adatomakh

4 September 2009 in 11:30

A. Shitov, D. Abanin, M. Rudner, L. Levitov

Besshchelevoi dirakovskii spektr kvazichastits v grafene privodit k interesnym transportnym yavleniyam, naprimer, k bezotrazhatel’nomu prokhozhdeniyu cherez bar’er (paradoks Kleina). V doklade budet pokazano, kak paradoks Kleina proyavlyaetsya v strukture ostsillyatsii soprotivleniya ballisticheskogo pnp-kontakta v magnitnom pole. Budet takzhe obsuzhdat’sya lokalizatsiya dirakovskikh kvazichastits adatomami (perestroika spektra, transportnye yavleniya).

Integriruemye sistemy i problemy algebraicheskoi geometrii

26 June 2009 in 11:30

I. Krichever

O zavisimosti dissipatsii poverkhnostnykh gravitatsionnykh voln ot stepeni nelineinosti

19 June 2009 in 11:30

V.E. Zakharov, A.O. Korotkevich, A.O. Prokof’ev

Kineticheskoe uravnenie dayot statisticheskoe opisanie dinamiki ansamblya voln. Ryad katastroficheskikh yavlenii nakhoditsya za ramkami statisticheskoi modeli. V sluchae gravitatsionnykh voln na poverkhnosti glubokoi zhidkosti, odnimi iz samykh chastykh i naibolee vazhnykh takikh protsessov yavlyayutsya obrushenie voln i formirovanie barashkov na grebnyakh. Ranee bylo pokazano, chto dannye effekty privodyat k dopolnitel’noi dissipatsii v raione spektral’nogo maksimuma voln, kotoruyu mozhno popytat’sya promodelirovat’ empiricheskim dissipativnym chlenom v kineticheskom uravnenii. S tsel’yu opredeleniya zavisimosti etogo chlena ot mery nelineinosti sistemy (krutizny ili srednego gradienta poverkhnosti) byli vypolneny dva chislennykh eksperimenta: slabonelineinyi v ramkakh 3D-gidrodinamiki i sil’nonelineinyi dlya 2D-gidrodinamiki. Oba eksperimenta nesmotrya na sushchestvenno razlichnye modeli i nachal’nye usloviya dali blizkie rezul’taty. Poluchennye dannye byli ispol’zovany dlya opredeleniya analiticheskoi formuly zavisimosti koeffitsienta zatukhaniya ot srednei krutizny volnovogo polya.

Quantum divisibility test and its application in mesoscopic physics

29 May 2009 in 11:30

G.B. Lesovik, M.V. Suslov, G. Blatter

We present a quantum algorithm to transform the cardinality of a set of charged particles flowing along a quantum wire into a binary number. The setup performing this task (for at most N particles) involves log2N quantum bits serving as counters and a sequential read out. Applications include a divisibility check to experimentally test the size of a finite train of particles in a quantum wire with a one-shot measurement and a scheme allowing to entangle multi-particle wave functions and generating Bell states, Greenberger-Horne-Zeilinger states, or Dicke states in a Mach-Zehnder interferometer.

Exact Haldane mapping for all S and super universality in spin chains

22 May 2009 in 11:30

A.M.M. Pruisken (ITP, University of Amsterdam)

The low energy dynamics of dimerised anti-ferromagnetic Heisenberg spin chains in the limit S → ∞ is known to map onto the O(3) nonlinear σ-model with a &thetasy; term in 1+1 dimension. By employing the underlying dual symmetry of the spin chain, as well as the recently established topological significance of “dangling edge spins”, we present an exact mapping onto the O(3) model that avoids the conventional large S idea altogether. Guided by numerical RG analyzes we show that the spin chain generally displays macroscopic quantization phenomena such as the Hall effect, as well as quantum criticality of the quantum Hall plateau transitions. Our results furthermore explain why the S = ∞ approximation generally yields the correct answer in spite of the fundamental complications in the idea of semiclassical expansions.

Uniaxially anisotropic antiferromagnets in a field along the easy axis

15 May 2009 in 11:30

W. Selke

In this talk, anisotropic Heisenberg antiferromagnents in a field are shown to display antiferromagnetic, spin-flop (or spin-liquid), and biconocal (or supersolid) phases. Results of theoretical analyses and related experiments are discussed.

Gidrodinamicheskie raschety s URS kondensirovannykh veshchestv

8 May 2009 in 11:30

V.A. Khokhlov, N.A. Inogamov, Yu.V. Petrov, S.I. Anisimov

Isparenie i razlet nagretogo veshchestva v prosteishei odnomernoi geometrii izuchaetsya s pomoshch’yu lagranzhevoi gidrodinamicheskoi chislennoi skhemy. Ispol’zovanie uravnenii sostoyaniya (URS) kondensirovannykh veshchestv (pri opredelennykh temperaturakh i plotnostyakh davlenie prokhodit cherez 0) privodit k novym effektam. Pri opredelennykh usloviyakh proiskhodit razryv sloya veshchestva. Dlya modelirovaniya effektov, proiskhodyashchikh pri vozdeistvii ul’trakorotkikh lazernykh impul’sov ispol’zuetsya dvukhtemperaturnaya model’. Rezul’taty gidrodinamicheskikh raschetov khorosho sootnosyatsya s molekulyarno-dinamicheskim modelirovaniem i rezul’tatami eksperimentov.

Spallative ablation of metals and dielectrics

17 April 2009 in 11:30

N.A. Inogamov, A.Ya. Faenov, V.A. Khokhlov, Yu.V. Petrov, V.V. Zhakhovskii, I.Yu. Skobelev, K. Nishihara, Y. Kato, M. Tanaka, T.A. Pikuz, M. Kishimoto, M. Ishino, M. Nishikino, Y. Fukuda, S.V. Bulanov, T. Kawachi

The paper presents results of theoretical and experimental investigations of ablation of dielectrics (LiF) by short soft X-ray pulse (ℏω = 89.3 eV, duration τL = 7 ps). It is found that there is a threshold for crater formation Fabl ≈ 10 mJ/cm2. This threshold is small in comparison with X-ray ablation by longer (ns) pulses. Theory explains this as a consequence of a change from more energy consuming evaporation ablation to spallative ablation when duration decreases from ns to ps. Previously spallative mechanism of ablation was attributed exclusively for the case of ℏω ~ 1 eV lasers and metal or semiconductor targets. Here we show that tensile stress created by short pulse in dielectrics even at relatively small X-ray fluences is able to cause spallative removal of target material.

Dva razlichnykh tipa gigantskikh voln v slabo-skreshchennykh sostoyaniyakh morskoi poverkhnosti

10 April 2009 in 11:30

V.P. Ruban

Formation of giant waves in sea states with two spectral maxima, centered at close wave vectors k0 ± Δ k/2 in the Fourier plane, is numerically simulated using the fully nonlinear model for long-crested water waves [V. P. Ruban, Phys. Rev. E 71, 055303(R) (2005)]. Depending on an angle θ between the vectors k0 and Δk, which determines a typical orientation of interference stripes in the physical plane, rogue waves arise having different spatial structure. If θ ≤ arctan(1/√2), then typical giant waves are relatively long fragments of essentially two-dimensional (2D) ridges, separated by wide valleys and consisting of alternating oblique crests and troughs. At nearly perpendicular k0 and Δk, the interference minima develop to coherent structures similar to the dark solitons of the nonlinear Shroedinger equation, and a 2D freak wave looks much as a piece of a 1D freak wave, bounded in the transversal direction by two such dark solitons.

Singulyarnye konechnozonnye operatory i indefinitnye metriki

10 April 2009 in 11:30

P.G. Grinevich, S.P. Novikov

Vo mnogikh sluchayakh veshchestvennye spektral’nye dannye dlya periodicheskikh konechnozonnykh operatorov (rimanova poverkhnost’ s otmechennoi tochkoi, lokal’nym parametrom i divizorom polyusov) porozhdayut operatory s veshchestvennymi, no singulyarnymi koeffitsientami. Eti operatory ne yavlyayutsya samosopryazhennymi v obychnykh (polozhitel’nykh) gil’bertovykh prostranstvakh funktsii peremennoi x. V chastnosti, takaya situatsiya imeet mesto dlya spetsial’nogo sluchaya operatorov Ermita s ellipticheskim potentsialom n(n+1)℘(x), sobstvennye funktsii kotorykh byli naideny Ermitom v 19 veke. V to zhe samoe vremya imenno funktsii Beikera-Akhiezera etikh operatorov, v sootvetstvii s ideyami rabot Krichevera-Novikova (1989), Grinevicha-Novikova (2001) sluzhat pravil’nymi analogami diskretnykh i nepreryvnykh bazisov Fur’e na rimanovykh poverkhnostyakh. Okazyvaetsya, chto dlya roda, otlichnogo ot nulya, eti operatory simmetrichny v nekotoroi indefinitnoi metrike. Analog nepreryvnogo preobrazovaniya Fur’e v etoi metrike yavlyaetsya izometriei.

Odnoklasternye modeli poristykh materialov i topologicheskie fazovye perekhody

3 April 2009 in 11:30

A.S. Ioselevich i D.S. Lyubshin

Rassmotreny modeli perkolyatsionnogo tipa, konfiguratsiya kotorykh v lyuboi moment yavlyaetsya svyaznoi. V takikh sistemakh vozmozhen (no ne obyazatelen) topologicheskii fazovyi perekhod, pri kotorom obrashchaetsya v nul’ plotnost’ ostova (backbone) -- nizhe tochki perekhoda makroskopicheskie provodimost’ i uprugost’ ravny nulyu. Issledovany voprosy ustoichivosti i universal’nosti perekhodov takogo tipa (po bol’shei chasti chislennymi metodami).

K voprosu o dissipatsionnoi funktsii poverkhnostnykh gravitatsionnykh voln, obuslovlennoi mikroobrusheniyami

27 March 2009 in 11:30

V.E. Zakharov, A.O. Korotkevich, A.O. Prokof’ev

Provedeny dva chislennykh eksperimenta po modelirovaniyu poverkhnostnykh gravitatsionnykh voln v ramkakh slabonelineinoi modeli dlya tryokhmernoi gidrodimnamiki i polnykh uravnenii dlya dvumernoi gidrodinamiki. Poluchena zavisimost’ dissipatsionnoi funktsii ot srednei krutizny poverkhnosti. Pokazano, chto dissipatsiya blagodarya mikroobrusheniyam imeet nestepennuyu zavisimost’ ot krutizny poverkhnosti.

Infrared catastrophe in two-quasiparticle collision integral

27 March 2009 in 11:30

O.V. Dimitrova, V.E. Kravtsov

Relaxation of a non-equilibrium state in a disordered metal with a spin-dependent electron energy distribution is considered. The collision integral due to the electron-electron interaction is computed within the approximation of a two-quasiparticle scattering. We show that the spin-flip scattering processes with a small energy transfer may lead to the divergence of the collision integral for a quasi one-dimensional wire. This divergence is present only for a spin-dependent electron energy distribution which corresponds to the total electron spin magnetization M = 0 and only for non-zero interaction in the triplet channel. The infrared cut-off which arises from the broadening of the energy levels by the electron-electron interaction is found to be of the order of the inverse dephasing time.

Fluktuatsionnyi effekt Nernsta v sverkhprovodnikakh

20 March 2009 in 11:30

M.N. Serbin, M.A. Skvortsov

Postroena teoriya fluktuatsionnogo effekta Nernsta v dvumernykh svekhprodnikakh v perpendikulyarnom magnitnom pole. V ramkakh matsubarovskoi diagrammnoi tekhniki polucheno vyrazhenie dlya koeffitsienta Nernsta, primenimoe kak vblizi, tak i vdali ot linii sverkhprovodyashchego perekhoda. Velichina effekta ostaetsya znachitel’noi vdali ot perekhoda i mozhet na poryadki prevyshat’ fermi-zhidkostnoi vklad. Naideny asimptotiki effekta Nernsta vo vsekh oblastyakh fazovoi diagrammy. Pokazano chto eksperimental’no nablyudaemye velichina i povedenie signala Nernsta khorosho ob’yasnyayutsya na osnove teorii sverkhprovodyashchikh fluktuatsii.

Effekt Dzhozefsona v dlinnom SINIS kontakte pri zadannom napryazhenii

13 March 2009 in 11:30

K.S. Tikhonov, M.V. Feigel’man

Rassmotren nestatsionarnyi effekt Dzhozefsona v SNS strukture s sil’nym normal’nym rasseyaniem na S/N granitsakh (soprotivlenie granitsy mnogo bol’she soprotivleniya normal’noi oblasti). Vychislena nestatsionarnaya popravka k funktsii raspredeleniya i «neravnovesnyi» sverkhprovodyashchii tok, v sluchae temperatur, mnogo bol’shikh energii Taulesa prevyshayushchii «ravnovesnyi» vklad za schet bolee medlennogo ubyvaniya s vozrastaniem temperatury. Pokazano, chto pri malykh napryazheniyakh i bol’shikh temperaturakh v toke preobladaet vtoraya garmonika

Sil’naya primes’ v kvantovoi provoloke

6 March 2009 in 11:30

D.N. Aristov (PIYaF RAN)

ostroena teoriya lattindzherovskoi zhidkosti s proizvol’noi tochechnoi primes’yu. Izvestno, chto v odnom prostranstvennom izmerenii dazhe slabaya primes’ pri nalichii ottalkivaniya mezhdu chastitsami «lokalizuet», to est’ provodimost’ (kondaktans) ischezaet v predele nulya temperatur. Eto yavlenie ranee issledovalos’ v predele slaboi primesi dlya proizvol’nogo vzaimodeistviya i dlya proizvol’noi primesi v sluchae slabogo vzaimodeistviya. V nashem podkhode primes’ kharakterizuetsya /S/-matritsei rasseyaniya i teoriya vozmushchenii stroitsya po vzaimodeistviyu fermionov, v obychnoi fermionnoi tekhnike. Okazyvaetsya, chto mozhno prosummirovat’ lineinye logarifmicheskie popravki k kondaktansu, naidya takim obrazom neperturbativnuyu /B/-funktsiyu v renorm-gruppovom podkhode. Poluchennoe analiticheskoe vyrazhenie dlya kondaktansa kak funktsii temperatury soglasuetsya s rezul’tatami, poluchennymi ranee metodami konformnoi teorii polya, i utochnyaet stepen’ ikh primenimosti.

Elektrony v kore vikhrya v sverkhprovodyashchem grafene

27 February 2009 in 11:30

N. Kopnin

Vychislyaetsya spektr svyazannykh elektronnykh sostoyanii v ostove mnogokvantovogo vikhrya v svnrkhprovodyashchem grafene. Issleduetsya problema sushchestvovaniya nulevykh mod v zavisimosti ot urovnya dopirovaniya.

Vliyanie sily tyazhesti i gidrodinamicheskikh dvizhenii na formu poverkhnosti vyazkoi zhidkosti kapillyarnogo razmera

20 February 2009 in 11:30

L.Yu. Barash

Uravneniya Nav’e-Stoksa i granichnye usloviya k nim dlya vyazkoi zhidkosti kapillyarnogo razmera sformulirovany v krivolineinykh koordinatakh, otvechayushchikh geometrii poverkhnosti. Eto pozvolyaet opisat’ gidrodinamiku kapel’ i meniskov i uchest’ vliyanie gidrodinamiki i sil tyazhesti na izmenenie formy poverkhnosti razdela zhidkost’-gaz. Provedeny otsenki rassmatrivaemykh effektov dlya isparyayushcheisya lezhashchei na podlozhke kapli.

Soprotivlenie zaryadovoi relaksatsii v zadache o kulonovskoi blokade

13 February 2009 in 11:30

Ya.I. Rodionov, I.S. Burmistrov, A.S. Ioselevich

Issleduetsya zadacha o dissipatsii energii v zadache o metallicheskom ostrovke, soedinennym tunnel’nym kontaktom s rezervuarom, i emkost’yu s zatvorom, na kotoroe podaetsya peremennoe napryazhenie. Formuly dlya dissipatsii energii s uchetom kulonovskoi energii na ostrovke polucheny v dvukh predel’nykh sluchayakh: malykh i bol’shikh kondaktansov tunnel’nogo kontakta. Poluchennye rezul’taty pozvolyayut sdelat’ predpolozhenie ob universal’nosti poluchennykh formul pri lyubykh kondaktansakh tunnel’nogo perekhoda.

Anomal’naya massovaya zavisimost’ energeticheskikh poter’ tyazhelykh kvarkov v kvark-glyuonnoi plazme konechnogo razmera

6 February 2009 in 11:30

B.G. Zakharov

Izoperodicheskie deformatsii billiardov na kvadrikakh

30 January 2009 in 11:30

Simonetta Abenda, P.G. Grinevich

Odna iz klassicheskikh integriruemykh sistem — geodezicheskie na ellipsoide. Nedavno bylo ustanovleno, chto esli v sistemu dobavit’ otrazhateli, zadavaemye konfokal’nymi ellipsoidami ili giperboloidami, to poluchayushchiisya billiard chastichno nasleduet svoistva integriruemosti. V dannoi rabote my pokazali, chto metod izoperiodicheskikh deformatsii, predlozhennyi renee Martinom Shmidtom i mnoi, mozhet byt’ ispol’zovan dlya postroeniya periodicheskikh billiardnykh traektorii.

Asimptoticheski tochnoe reshenie zadachi ob optimal’noi fluktuatsii uprugoi struny v sluchainom potentsiale

23 January 2009 in 11:30

I.V. Kolokolov, S.E. Korshunov

Vychislenie topologicheskogo zaryada konechnozonnykh reshenii uravneniya Sinus-Gordon s ispol’zovaniem teta-funktsional’nykh formul

16 January 2009 in 11:30

P.G. Grinevich, Krishna Kaipa

Odna iz naibolee vazhnykh kharakteristik konechnozonnykh reshenii Sinus-Gordona — topologicheskii zaryad. Zadacha ego vychisleniya byla postavlena prakticheski srazu posle togo, kak byli vypisany yavnye formuly dlya reshenii. Otvet dlya chasti prostranstva parametrov byl poluchen B.A. Dubrovinym i S.P. Novikovym v 1982 godu, odnako formulu dlya obshchego sluchaya udalos’ naiti lish’ v 2001 godu S.P. Novikovym i P.G. Grinevichem. Pri etom ispol’zovalsya tak nazyvaemyi algebro-topologicheskii podkhod, a yavnye teta-funktsional’nye resheniya nikak ne ispol’zovalis’. V svyazi s etim S.P. Novikovym byl postavlen vopros o vychislenii topologicheskogo zaryada s ispol’zovaniem teta-funktsii, otvet na kotoryi my i daem.

Opredelenie postoyannoi tonkoi struktury (vpervye v fizike kondensirovannogo sostoyaniya) v opticheskikh spektrakh grafena

11 January 2009 in 11:30

L.A. Fal’kovskii

Osobennosti dielektricheskoi funktsii u MnN

11 January 2009 in 11:30

L.A. Fal’kovskii

Rassmotrena chastotnaya dispersiya dielektricheskoi pronitsaemosti InN so strukturoi vyurtsita v oblasti chastot vblizi fundamental’noi energeticheskoi shcheli v zavisimosti ot temperatury i kontsentratsii nositelei. Lineinost’ elektronnogo spektra v shirokoi energeticheskoi oblasti privodit k logarifmicheskoi singulyarnosti v veshchestvennoi chasti dielektricheskoi pronitsaemosti, svyazannoi s pryamymi elektronnymi perekhodami, i, sootvetstvenno, k anomal’no bol’shoi velichine dielektricheskoi postoyannoi. Mnimaya chast’ vykhodit na plato vyshe poroga pogloshcheniya.

Zasedanie Dissertatsionnogo soveta ITF

26 December 2008 in 11:30

A.Yu. Men’shutin

Zashchita kandidatskoi dissertatsii A.Yu. Men’shutina «O kriticheskikh svoistvakh pri roste klasterov DLA.

Korrelyatsionnye funktsii v konformnoi teorii polya, teorii Liuvillya i dvumernoi gravitatsii

26 December 2008 in 11:30

A.V. Litvinov

Vliyanie kondensata na slaboturbulentnye spektry

19 December 2008 in 11:30

A.O. Korotkevich

Rassmotrena zadacha ob izotropnoi turbulentnosti ideal’noi zhidkosti. Proizvedyon chislennyi eksperiment v ramkakh gamil’tonovskikh uravnenii dinamiki poverkhnosti ideal’noi zhidkosti. V chislennom eksperimente poluchenny spektry pryamogo i obratnogo kaskadov volnovoi turbulentnosti. Takzhe otmecheno formirovanie dlinnovolnovogo fona (kondensata). V prisutstvii kondensata eksponenty spektrov otlichayutsya ot predskazyvaemykh teoriei slaboi turbulentnosti. Pri unichtozhenii kondensata spektry vozvrashchayutsya k teoreticheskim. Dano kachestvennoe ob’yasnenie nablyudaemogo effekta. Dannaya situatsiya kharakterna dlya eksperimental’nykh volnovykh basseinov. Rabota pozvolyaet predlozhit’ ob’yasnenie razlichiyu volnovykh turbulentnykh spektrov, nablyudaemykh v eksperimental’nykh basseinakh i na otkrytoi vode.

Formfaktory operatorov-potomkov i otrazhatel’nye sootnosheniya

12 December 2008 in 11:30

B. Feigin, M. Lashkevich

Vychislenie tochnykh formfaktorov lokal’nykh operatorov v integriruemykh modelyakh kvantovoi teorii polya svoditsya, kak izvestno, k resheniyu spetsial’noi sistemy raznostnykh uravnenii na analiticheskie funktsii. Slozhnost’ zaklyuchaetsya v tom, chtoby otozhdestvit’ resheniya etikh uravnenii s konkretnymi polyami. V dannoi rabote polucheny nekotorye rezul’taty v etom napravlenii dlya modeli sh-Gordona i brizernogo sektora modeli sinus-Gordona. Predlozheno nekotoroe opisanie reshenii operatornykh uravnenii dlya operatorov-potomkov v etikh modelyakh. Pokazano, chto podschet reshenii etikh uravnenii v tochkakh obshchego polozheniya sovpadaet s podschetom lokal’nykh operatorov. Krome togo, pokazano, chto formfaktory udovletvoryayut tak nazyvaemym otrazhatel’nym sootnosheniyam, svyazyvayushchim potomki eksponentsial’nykh operatorov ei&alphaϖ i ei(2&alpha0-α)ϖ (s nekotorym &alpha0 zavisyashchim ot parametrov modeli).

Weak continuous measurements of multiqubits systems

5 December 2008 in 11:30

E. Il’ichev (Institute of Photonic Technology, Jena, Germany)

We review the recent results of experimental study of superconducting qubits. A low frequency superconducting tank circuit is used as a detector for their characterization. Sisyphus mechanism of exchange energy between tank circuits and flux qubit is shown. Consistency between ground state and spectroscopic measurements is demonstrated. A fixed ferromagnetic, antiferromagnetic as well as tunable qubit-qubit coupling is realized. We argue that the ground state measurements can be used for characterization of N coupled flux qubits.

Kraevye opticheskie mody v fotonnykh zhidkikh kristallakh i nizkoporogovaya lazernaya generatsiya

5 December 2008 in 11:30

V.A. Belyakov

Predstavlen kratkii obzor nedavnikh eksperimental’nykh i teoreticheskikh rabot v oblasti nizkoporogovoi lazernoi generatsii s raspredelennoi obratnoi svyaz’yu (ROS) v kiral’nykh zhidkikh kristallakh (KZhK), a takzhe novye original’nye teoreticheskie rezul’taty v etoi oblasti. Osnovnoe vnimanie udelyaetsya porogam lazernoi generatsii na chastotakh v oblasti chastot kraevykh opticheskikh mod v KZhK. prodemonstrirovano, chto analiticheskii podkhod k probleme ne tol’ko vosproizvodit vse rezul’taty, poluchennye chislennymi metodami, no i pozvolyaet vyyavit’ ryad kachestvennykh effektov, ne vyyavlennykh v chislennykh issledovaniyakh zadachi. A imenno, vyyavlen effekt anomal’no sil’nogo pogloshcheniya sveta na chastote kraevoi mody. Vyyavlena vozmozhnost’ ponizheniya poroga lazernoi generatsii s raspredelennoi obratnoi svyaz’yu v kiral’nykh zhidkikh kristallakh putem realizatsii nakachki v usloviyakh ee anomal’no sil’nogo pogloshcheniya na chastote kraevoi mody. Razvityi podkhod proyasnyaet fiziku lazernoi ROS generatsii na chastotakh v oblasti chastot kraevykh opticheskikh mod v KZhK i demonstriruet soglasie s eksperimentom i rezul’tatami predshestvuyushchikh rabot, vypolnennykh v ramkakh chislennogo podkhoda k izuchaemoi probleme.

Spinovyi effekt Kholla v SNS dzhozefsonovskom kontakte

28 November 2008 in 11:30

A.G. Mal’shukov, Institut spektroskopii RAN

Issledovan spinovyi effekt Kholla pri dzhozefsonovskom tunnelirovanii cherez SNS-kontakt, gde iz-za spin-orbital’nogo vzaimodeistviya zona provodimosti v normal’noi oblasti rasshcheplena po spinu. V ramkakh diffuzionnogo priblizheniya vyvedeno sootvetstvuyushchee uravnenie Uzadelya. Pokazano, chto v sluchae statsionarnogo effekta Dzhozefsona spinovyi effekt Kholla privodit k poyavleniyu spinovoi plotnosti po bokovym krayam N-oblasti. V to zhe vremya, spinovyi tok, obychno voznikayushchii v sluchae normal’nogo spinovogo effekta Kholla, otsutstvuet v usloviyakh statsionarnogo sverkhprovodyashchego transporta. Etot tok,odnako, otlichen ot nulya pri nestatsionarnom effekte Dzhozefsona.

Kulonovskaya blokada, kulonovskaya anomaliya i neuprugoe kotunnelirovanie v protyazhennom ob’ekte: tunnel’nyi perenos zaryada cherez dlinnyi kusok provoloki

21 November 2008 in 11:30

M.V. Feigel’man, A.S. Ioselevich

Issledovano vliyanie kulonovskikh effektov na soprotivlenie dlinnoi provoloki, soedinennoi s vneshnei tsep’yu cherez vysokoomnye tunnel’nye kontakty. Pri otnositel’no vysokikh temperaturakh temperaturnaya zavisimost’ soprotivleniya opredelyaetsya khorosho izvestnoi kulonovskoi anomaliei, opisyvayushchei rastekanie zaryada pri tunnelirovanii odinochnogo elektrona (ili odinochnoi dyrki) v beskonechnyi odnomernyi provodnik, a soprotivlenie sistemy eksponentsial’no rastet pri ponizhenii temperatury (ili napryazheniya). Pri bolee nizkikh temperaturakh, odnako, sistema dolzhna perekhodit’ v neobychnyi rezhim neuprugogo kotunnelirovaniya, v kotorom elektron i dyrka odnovremenno pronikayut v provod s raznykh kontsov i proiskhodit sovmestnoe rastekanie ikh zaryadov. Zdes’ soprotivlenie zavisit ot temperatury tol’ko stepennym obrazom, prichem pokazatel’ stepeni proportsionalen rasstoyaniyu mezhdu kontaktami. Effekt rastekaniya zaryada v rezhime kulonovskoi blokady dlya otnositel’no korotkikh provolok proyavlyaetsya v vozniknovenii, naryadu s obychnoi aktivatsionnoi eksponentoi, dopolnitel’nogo eksponentsial’no malogo faktora. On zavisit ot temperatury i opisyvayuet tunnel’noe rastekanie zaryada, predshestvuyushchee vozniknoveniyu metastabil’nogo zaryazhennogo sostoyaniya. V rezonansnom sluchae, kogda energiya zaryazheniya provoloki blizka k nulyu, effekt rastekaniya voobshche dominiruet, pri etom temperaturnaya zavisimost’ polnogo kondaktansa stanovitsya ne aktivatsionnoi, a stepennoi, prichem pokazatel’ stepeni proportsionalen polnoi dline provoloki i sil’no zavisit ot polozheniya kontaktov po otnosheniyu k ee kontsam.

Evidence of criticality in DLA model

14 November 2008 in 11:30

A.Yu. Men’shutin, L.N. Shchur

My ispol’zovali razrabotannyi ranee bezreshetochnyi algoritm generatsii DLA (Diffusion limited aggregation) klasterov s modifikatsiei orientatsii prilipaniya diffundiruyushchei chastitsy: pri prilipanii ona mozhet zanyat’ lish’ schetnoe chislo Nfp orientirovannykh v prostranstve polozhenii na poverkhnosti chastitsy, kotoroi ona kosnulas’. V predele beskonechnogo chisla Nfp polozhenii algoritm polnost’yu ekvivalenten kanonicheskomu algoritmu. Pri Nfp = 3 i 4 metod privodit k generatsii klasterov, analogichnykh diffuzii na geksagonal’noi i kvadratnoi reshetke, sootvetstvenno. Dlya Nfp = 3–8 sgenerirovano po 1000 klasterov iz 50 millionov chastits kazhdyi. Fraktal’naya razmernost’ kazhdogo klastera issledovana s pomoshch’yu ranee predlozhennogo avtorami metoda probnykh chastits peremennogo radiusa. Otsenena takzhe plotnost’ chastits klastera po uglu i po poverkhnosti i issledovany ee svoistva. Vyskazyvaetsya gipoteza o sushchestvovanii kriticheskogo znacheniya dlya Nfp: pri znacheniyakh Nfp, men’shikh kriticheskogo, fraktal’naya razmernost’, po-vidimomu, ubyvaet s razmerom klastera, v to vremya, kak pri bol’shikh znacheniyakh ona asimptoticheski stremitsya k fraktal’noi razmernosti bezreshetochnykh klasterov.

Kinematicheskoe dinamo v sil’nom sdvigovom techenii

7 November 2008 in 11:30

V. Kogan, I. Kolokolov, V. Lebedev

Sverkhprovodimost’ v grafene

31 October 2008 in 11:30

N.B. Kopnin

Rassmatrivaetsya vozmozhnoe sverkhprovodyashchee sostoyanie v sisteme elektronov, obladayushchei v normal’nom sostoyanii konicheskim spektrom s dirakovskoi tochkoi. Vychislyayutsya kriticheskaya temperatura, sverkhprovodyashchaya shchel’ i sverkhtok.

Evaporation and fluid dynamics of a sessile drop of capillary size

24 October 2008 in 11:30

L.Yu. Barash

Theoretical description and numerical simulation of an evaporating sessile drop are developed. We jointly take into account the hydrodynamics of an evaporating sessile drop, effects of the thermal conduction in the drop and the diffusion of vapor in air. Simulation results agree well with the evaporation rate measurements. Marangoni forces associated with the temperature dependence of the surface tension, generate fluid convection in the sessile drop. Our results demonstrate several dynamical stages of the convection charaterized by different number of vortices in the drop.

Bose-Einstein condensation and superfluidity of magnons in superfluid 3He

17 October 2008 in 11:30

G.E. Volovik

Bose-Einstein condensation of magnetic excitations (magnons) has been observed in superfluid 3He-B in 1984. Magnon BEC is manifested as spontaneous formation of the domain in which magnetization is freely precessing with the phase coherent throughout the whole domain even in the presence of inhomogeneous external magnetic fields. Spin-superfluid properties of this domain (HPD) have been verified in a number of experiments: magnetization transport via spin supercurrent (the analog of a mass current in conventional superfluids): phase-slip processes at a critical spin current; the spin-current Josephson effect; the topological defect — spin current vortex. The Goldstone mode originating from the U(1) symmetry breaking has been also observed; it represents phonons — sound waves in compressible magnon liquid — in a full correspondence with Landau theory of superfluidity. However as distinct from the conventional superfluids, in magnon superfluid it is easy to introduce experimentally the symmetry breaking field, which induces the mass of the phonon. In addition to HPD, several other states of coherent precession have been recently observed in superfluid 3He: two new modes of coherent precession in compressed aerogel; analogs of /Q/-balls at very low temperatures; magnon BEC in 3He-A; etc.

Laser ablation of aluminum and gold

10 October 2008 in 11:30

N.A. Inogamov

Duration of femtosecond laser pulse (fsLP) τL ~ 40–100 fs is shorter than characteristic times of (1) electron-ion thermal relaxation, (2) melting of overheated crystal lattice, and (3) cavitation decay of metastable state. Thus the fsLP with moderate intensity ~ 1013 W/cm2 results in non-equilibrium processes (1, 2, 3). These processes have very various time scales from subpicoseconds to nanoseconds. The theory of these processes and related experiments are the subject of the report. Two-temperature (2T) hydrodynamics (2Thd) and molecular dynamics (MD) codes are used. The physical model includes the 2T equation of state (EOS), many-body interatomic potential, electron-ion energy exchange, electron thermoconductivity, and model describing optical properties. Experimental setup with pump-probe technique is used to follow evolution of irradiated target with short time step 100 fs between the probe fsLP and ~ 1 % accuracy of measurement of reflection coefficient and ~ 1 nm accuracy of measurement of the probe phase. It is found that, firstly, in solid Al the electron-electron collisions make a minor contribution to the light absorbtion, secondly, the phase shift of reflected probe results from kinetics of melting of Al during 0

Numerical revision of the universal amplitude ratios for the two-dimensional 4-state Potts model

3 October 2008 in 11:30

L.N. Shchur

Monte Carlo (MC) simulations and series expansion (SE) data for the energy, specific heat, magnetization and susceptibility of the ferromagnetic 4-state Potts model on the square lattice are analyzed in a vicinity of the critical point in order to estimate universal combinations of critical amplitudes. The quality of the fits is improved using predictions of the renormalization group (RG) approach and of conformal invariance, and restricting the data within an appropriate temperature window.
The RG predictions on the cancelation of the logarithmic corrections in the universal amplitude ratios are tested. A direct calculation of the effective ratio of the energy amplitudes using duality relations explicitly demonstrates this cancelation of logarithms, thus upporting the predictions of RG.
We emphasize the role of corrections of background terms on the determination of the amplitudes. The ratios of the critical amplitudes of the susceptibilities obtained in our analysis differ significantly from those predicted theoretically and supported by earlier SE and MC analysis. This disagreement might signal that the two-kink approximation used in the analytical estimates is not sufficient to describe with fair accuracy the amplitudes of the 4-state model.

Indutsirovannaya sverkhprovodimost’ v grafene

26 September 2008 in 11:30

M.V. Feigel’man, M.A. Skvortsov i K.S. Tikhonov

Predskazano, chto odinochnyi list grafena mozhet byt’ sdelan makroskopicheski sverkhprovodyashchim s temperaturoi perekhoda poryadka neskol’kikh Kel’vin putem osazhdeniya na nem sverkhprovodyashchikh ostrovkov zanimayushchikh v tselom maluyu dolyu ploshchadi lista. Voznikayushchaya sverkhprovodimost’ soderzhit cherty kak nepreryvnogo neodnorodnogo sverkhprovodnika, tak i reshetki slabykh kontaktov.

Vodno-volnovye shchelevye solitony: Priblizhennaya teoriya i «tochnyi» chislennyi eksperiment

19 September 2008 in 11:30

V.P. Ruban

Pokazano, chto standartnaya teoriya svyazannykh mod mozhet uspeshno opisyvat’ slabo-nelineinye gravitatsionnye volny na vode, nakhodyashchiesya v Breggovskom rezonanse s periodicheskoi odnomernoi topografiei dna. Analiticheskie resheniya dlya t.n. shchelevykh solitonov, dayushchiesya etoi teoriei, khorosho soglasuyutsya s rezul’tatami vysoko-tochnogo chislennogo modelirovaniya potentsial’nykh techenii so svobodnoi poverkhnost’yu, dazhe v sluchae sil’no nelineinykh voln. Pokazano, chto vozmozhny ochen’ dolgozhivushchie samolokalizovannye gruppy stoyachikh voln na vode. V nekotoroi oblasti «solitonnykh» parametrov, vodno-volnovye shchelevye solitony sushchestvuyut na protyazhenii soten volnovykh periodov, poka neuchtennye prostoi model’yu protsessy ne izmenyat ikh sushchestvenno.

Elektronnaya struktura i transportnye svoistva smeshannogo sostoyaniya mezoskopicheskikh sverkhprovodnikov

5 September 2008 in 11:30

M.A. Silaev (IFM RAN, Nizhnii Novgorod)

Rabota posvyashchena issledovaniyu spektra kvazichastits v smeshannom sostoyanii mezoskopicheskikh sverkhprovodnikov. Rasschitany elektronnye spektry dlya razlichnykh vikhrevykh struktur v mezoskopicheskikh sverkhprovodnikakh. Issledovany zavisimosti ot magnitnogo polya transportnykh kharakteristik sverkhprovodnika. Pokazano, chto teplovoi kondaktans v napravlenii vdol’ vikhrevykh linii rastyot pri sblizhenii vikhrei s rostom vneshnego magnitnogo polya. Rost teplovogo kondaktansa obuslovlen perestroikoi spektra kvazichastits, privodyashchei k uvelicheniyu chisla rasprostranyayushchikhsya mod. Naideno, chto povyshenie kontsentratsii vikhrei v ballisticheskom kontakte normal’nyi metall/izolyator/sverkhprovodnik privodit k znachitel’nomu uvelicheniyu provodimosti kontakta s rostom magnitnogo polya. Takoe povedenie provodimosti vyzvano rezonansnymi perekhodami elektronov iz normal’nogo kontakta v kvazichastichnye sostoyaniya, lokalizovannye na vikhryakh. Takzhe izucheno povedenie anomal’nykh vetok spektra poverkhnostnykh i vikhrevykh sostoyanii v mezoskopicheskom kiral’nom sverkhprovodnike v magnitnom pole i naidena zavisimost’ plotnosti sostoyanii na urovne Fermi ot napravleniya i velichiny prilozhennogo magnitnogo polya.

Thermodynamics and dynamics of the vacuum energy and cosmological constant

5 September 2008 in 11:30

G.E. Volovik

The development of high-energy physics and cosmology over the last years has led to the realization that, most likely, Einstein‘s theory of gravity needs to be modified. Our proposal is based on the treatment of the Lorentz-invariant quantum vacuum as an extended self-sustained system characterized by a conserved relativistic charge q describing the physics of the deep (ultraviolet) vacuum. This treatment allows us to discuss both the thermodynamics and the dynamics of a Lorentz-invariant quantum vacuum. The thermodynamic approach demonstrates that the vacuum energy density appears in two forms: the microscopic energy characterized by the Planck energy scale, and the macroscopic energy which contributes to the gravitational field equations as the cosmological constant. For a self-sustained vacuum in full thermodynamic equilibrium and in the absence of matter, the macroscopic vacuum energy is automatically nullified without fine tuning. The dynamics demonstrates how, in a flat Friedmann-Robertson-Walker universe, the vacuum energy density and the effective cosmological «constant» relax from the natural Planck-scale value at early Planckian times to a naturally small value at late times.

Opisanie kvantovogo zaputyvaniya s pomoshch’yu nil’potentnykh polinomov

11 June 2008 in 11:30

V. Akulin (Orsay University)

Uedinyonnye volny v breggovskoi reshyotke

11 June 2008 in 11:30

A.O. Korotkevich

Izucheno rasprostranenie sveta v breggovskoi periodicheskoi strukture soderzhashchei tonkie plyonki s rezonasnymi chastitsami. Chastoty rezonansa chastits, breggovskogo rezonansa i opticheskoi nesushchei volny predpolagayutsya blizkimi. Naideny i izucheny tochnye resheniya opisyvayushchie uedinyonnye volny v dannoi sisteme. Takzhe rassmotreno yavlenie ostanovki sveta vsledstvie angarmonichnosti ostsillyatsii v chastitsakh.

Opticheskie svoistva 2d i 3d provodnikov s lineinym spektrom

6 June 2008 in 11:30

L.A. Fal’kovskii

Rassmotrena chastotnaya dispersiya dielektricheskoi pronitsaemosti grafena i poluprovodnikov A4B6 v oblasti chastot, bol’shikh, chem chastota relaksatsii nositelei, no malykh po sravneniyu s shirinoi zony provodimosti, v zavisimosti ot temperatury i kontsentratsii nositelei. Skhodstvo etikh materialov — lineinost’ elektronnogo spektra v shirokoi energeticheskoi oblasti privodit k logarifmicheskoi singulyarnosti u veshchestvennoi chasti dielektricheskoi pronitsaemosti, svyazannoi s pryamymi elektronnymi perekhodami, i sootvetstvenno, k anomal’no bol’shoi velichine dielektricheskoi postoyannoi u A4B6. Otlichie v razmernosti, ravnoi trem u poluprovodnikov i dvum u grafena, vyrazhaetsya v razlichnom kharaktere plazmonov, kotorye mogut sushchestvovat’ pri vysokom dopirovanii ili v usloviyakh «effekta polya».

Tochnye resheniya dvumernoi periodicheskoi tsepochki Vol’terra. Nelineinye volnovye fronty i kaskady solitonnykh raspadov

30 May 2008 in 11:30

Aleksandr V. Mikhailov

Naideny novye klassy tochnykh reshenii, otvechayushchikh frontu nelineinoi volny, interfeisam mezhdu frontami i nelineinoi interferentsii voln. Eti resheniya byli polucheny pri izuchenii dvumernogo obobshcheniya tsepochki Vol’terra. V etoi sisteme takzhe naideny resheniya otvechayushchie kaskadu solitonnykh raspadov (ili sliyanii). Klassifikatsiya poluchennykh reshenii estestvennym obrazom svyazana s Shubertovskim razlozheniem Grassmanianov.

O vektornykh analogakh tsepochki Vol’terra

23 May 2008 in 11:30

V. Adler, V. Postnikov

Poluchena klassfikatsiya, v ramkakh simmetriinogo podkhoda, integriruemykh tsepochek tipa Vol’terra na sfere. Obsuzhdaetsya ikh simplekticheskaya struktura i assotsiirovannye sistemy tipa NUSh. Rassmotreny takzhe nekotorye primery polinomial’nykh tsepochek bez reduktsii na sferu.

500-e reshenie 2D modeli Izinga

18 April 2008 in 11:30

S.N. Vergeles

Naideno eshche odno reshenie dvumernoi modeli Izinga.

Sil’no nelineinye Breggovskie kvazi-solitony v dinamike voln na vode

11 April 2008 in 11:30

V.P. Ruban

Tunnelirovanie cherez kvaziodnomernyi provodnik

4 April 2008 in 11:30

A.S. Ioselevich, M.V. Feigel’man

Issledovano vliyanie kulonovskikh effektov na soprotivlenie dlinnoi (po sravneniyu s dlinoi lokalizatsii) provoloki, soedinennoi s vneshnei tsep’yu cherez vysokoomnye tunnel’nye kontakty. Pri otnositel’no vysokikh temperaturakh temperaturnaya zavisimost’ soprotivleniya opredelyaetsya khorosho izvestnoi kulonovskoi anomaliei, opisyvayushchei rastekanie zaryada pri tunnelirovanii odinochnogo elektrona (ili odinochnoi dyrki) v beskonechnyi odnomernyi provodnik, a soprotivlenie sistemy eksponentsial’no rastet pri ponizhenii temperatury. Pri bolee nizkikh temperaturakh, odnako, sistema dolzhna perekhodit’ v neobychnyi rezhim neuprugogo kotunnelirovaniya, v kotorom elektron i dyrka odnovremenno pronikayut v provod s raznykh kontsov i proiskhodit sovmestnoe rastekanie ikh zaryadov. Zdes’ soprotivlenie zavisit ot temperatury tol’ko stepennym obrazom, prichem pokazatel’ stepeni proportsionalen rasstoyaniyu mezhdu kontaktami.

Reologicheskie svoistva vzvesi vezikul

28 March 2008 in 11:30

S.S. Vergeles

Issledovany reologicheskie svoistva vzvesi vezikul v predele sil’nykh potokov, razrushayushchikh statsionarnuyu formu vezikul. Dlya sluchaya ploskogo techeniya poluchena zavisimost’ effektivnoi vyazkosti suspenzii ot gradienta skorosti i svoistv vezikul. Ustanovleno, v chastnosti, chto effektivnaya vyazkost’ suspenzii mozhet zaviset’ ot eyo nachal’nogo sostoyaniya. Proanalizirovano vliyanie teplovykh fluktuatsii na reologicheskie svoistva suspenzii.

Odnovremennoe nablyudenie pryamogo i obratnogo kaskadov v turbulentnosti poverkhnostnykh gravitatsionnykh voln

21 March 2008 in 11:30

A.O. Korotkevich

Posredstvom pryamogo chislennogo modelirovaniya byli polucheny pryamoi i obratnyi kaskady v turbulentnosti poverkhnostnykh gravitatsionnykh voln. Obrazovanie kondensata v oblasti nizkikh chastot privodit k iskazheniyu eksponent v Kolmogorovskikh spektrakh predskazannykh teoriei slaboi turbulentnosti. Predozhenno kachestvennoe ob’yanenie dannogo protsessa. Takzhe nablyudalos’ vliyanie diskretnosti setki volnovykh vektorov. Parametry modelirovaniya tipichny dlya laboratornykh eksperimentov v volnovykh basseinakh.

Bifurkatsii, ustoichivost’ i kollaps poverkhnostnykh solitonov ogibayushchikh dlya zhidkosti konechnoi glubiny

21 March 2008 in 11:30

D. Agafontsev

Parnikovyi effekt: analiticheskoe reshenie

14 March 2008 in 11:30

A. Byalko

Komp’yuternoe modelirovanie, kak sovremennogo klimata, tak i klimata proshlogo dostiglo zametnykh uspekhov, chto ne otmenyaet neobkhodimost’ analiticheskogo podkhoda, pozvolyayushchego sledit’ za povedeniem slozhnoi sistemy prostym izmeneniem vkhodnykh parametrov. V rabote provoditsya issledovanie parnikovogo effekta iskhodya iz printsipa postoyanstva ukhodyashchego potoka mikrovolnovogo izlucheniya pri izmenenii kontsentratsii dioksida ugleroda.

Gigantskie brizery na poverkhnosti zhidkosti

7 March 2008 in 11:30

A.I. D’yachenko

Vydvizhenie kandidatov ot ITF na vybory deistvitel’nykh chlenov i chlenov-korrespondentov RAN v 2008 g

7 March 2008 in 11:30

Vliyanie spinovogo i dolinnogo rasshchepleniya na transport v dvumernoi neuporyadochennoi elektronnoi zhidkosti

29 February 2008 in 11:30

I.S. Burmistrov, N.M. Shchelkachev

V rabote issleduetsya vliyanie spinovogo i dolinnogo rasshcheplenii na soprotivlenie, spinovuyu i dolinnuyu vospriimchivosti dvumernoi neuporyadochennoi elektronnoi zhidkosti. V doklade budet rasskazano o odnopetlevykh uravneniyakh renorm-gruppy, kotorye opisyvayut sistemu v dvukh oblastyakh ΔsT ≪ Δv i T ≪ Δs ≪ Δv, gde T — temperatura, Δs — spinovoe rasshcheplenie, i Δv — dolinnoe rasshcheplenie. S pomoshch’yu poluchennykh uravnenii renorm-gruppy nam udalos’ kachestvenno ob’yasnit’ proiskhozhdenie nemonotonnoi zavisimosti soprotivleniya ot temperatury, kotoraya nablyudaetsya eksperimental’no v parallel’nom magnitnom pole, a takzhe predskazat’ vozmozhnost’ nablyudeniya novogo tipa nemonotonnogo povedeniya, pri kotorom soprotivlenie kak funktsiya temperatury imeet dva maksimuma.

Principles of emergent symmetries from topology in momentum space

22 February 2008 in 11:30

G.E. Volovik

Konechnozonnaya teoriya reshenii uravnenii s samomsoglasovannymi istochnikami v pravoi chasti

8 February 2008 in 11:30

P.G. Grinnevich, I.A. Taimanov

Uravneniya s samosoglasovannymi istochnikami v pravoi chasti byli vvedeny Mel’nikovym, a takzhe Zakharovym i Kuznetsovym. My izuchaem ikh konechnozonnye resheniya. Pokazano, chto pri nekotorom vybore istochnikov v pravoi chasti oni yavlyayutsya pochti izospektral’nymi -- deformatsiya spektral’noi krivoi svoditsya k dobavleniyu ili udaleniyu dvoinykh tochek, pri etom vse lokal’nye zakony sokhraneniya ostayutsya invariantnymi.

Ob odnoi nelineinoi zadache na sobstvennye znacheniya

1 February 2008 in 11:30

A.B. Shabat

Temperaturnaya zavisimost’ spektra elektronov, levitiruyushchikh nad tverdym vodorodom

18 January 2008 in 11:30

P.D. Grigor’ev, A.M. Dyugaev, E.V. Lebedeva

Na osnove opytnykh dannykh i prostoi modeli kondensirovannogo vodoroda predlozhena teoriya fotorezonansnykh perekhodov dlya elektronov, lokalizovannykh nad poverkhnost’yu tverdogo N2. Dano novoe ob’yasnenie obnaruzhennoi eksperimental’no sil’noi zavisimosti chastot perekhodov ot davleniya parov vodoroda. V otlichie ot imevshikhsya ranee predstavlenii, osnovannykh na vydelenii effektov kvantovogo prelomleniya elektronov na atomakh para N2, temperaturnaya zavisimost’ chastot perekhodov ν svyazyvaetsya nami s neodnorodnost’yu para. Na opyte imeet mesto neanaliticheskaya zavisimost’ ν ot plotnosti para nν: ν ∼ nνγ ∼ eΔ/T, γ = 0.56 . Energiya aktivatsii Δ otvechaet «nepolnomu ispareniyu» tverdogo vodoroda. Parametr Δ men’she energii «polnogo ispareniya» tverdogo vodoroda, ravnoi 92.6 K.

Nepreryvnyi predel stokhasticheskoi kletochnoi modeli Pottsa dlya biologicheskikh kletok

11 January 2008 in 11:30

Pavel Lushnikov

oluchen nepreryvnyi predel dvumernoi stokhasticheskoi kletochnoi modeli Pottsa (KMP), kotoraya opisyvaet biologicheskie kletki dvizhushchiesya v srede i vzaimodeistvuyushchie drug s drugom za schet pryamogo kontakta, prilipaniya drug k drugu i khemotaksica. Vse koeffitsieny makroskopicheskoi modeli, kotoraya imeet vid uravneniya Fokkera-Planka dlya evolyutsii plotnosti kletok, vyvedeny iz parametrov KMP. Prodemonstrirovano ochen’ khoroshee sootvetstvie mezhdu Monte-Karlo modelirovaniem KMP i chislennym resheniem makroskopicheskogo uravneniya. Takzhe pokazano chto, v otsutstvie kontaktnykh vzaimodeistvii mezhdu kletkami, poluchennaya model’ svodyatsya k klassicheskoi modeli Kellera-Segela.

Zashchita kandidatskoi dissertatsii R.B. Saptsova «Kinetika fazovykh perekhodov vtorogo roda s obrazovaniem boze-kondensata

28 December 2007 in 11:30

Svoistva sverkhprovodyashchego sostoyaniya, voznikayushchego na fone volny spinovoi ili zaryadovoi plotnosti

21 December 2007 in 11:30

Pavel Grigor’ev

V rabote izucheny mikroskopicheskaya struktura i svoistva sverkhprovodimosti, voznikayushchei na fone volny zaryadovoi (VZP) ili spinovoi plotnosti (VSP). Traditsionno schitalos’, chto eti dva sovershenno razlichnykh sostoyaniya mogut sosushchestvovat’, tol’ko esli v metalle obrazuetsya makroskopicheskaya domennaya struktura, prostranstvenno razdelyayushchaya eti dve fazy (v protivnom sluchae obrazovanie shcheli v elektronnom spektre iz-za obrazovaniya VzP ili VSP privodit k eksponentsial’nomu umen’sheniyu temperatury sverkhprovodyashchego perekhoda). Odnako mnogie sverkhprovodniki s volnoi plotnosti ne opisyvayutsya takoi prostoi model’yu. Nedavnie eksperimenty na organicheskikh metallakh (TMTSF)2PF6 i a-(BEDT-TTF)2KHg(SCN)4 chetko pokazali, chto eto ne vsegda tak. V etikh veshchestvakh sverkhprovodimost’, mikroskopicheski sosushchestvoyushchaya s VSP i VZP sootvetstvenno, imeet priblizitel’no takuyu zhe temperaturu perekhoda, chto i bez volny plotnosti, i obladaet ryadom kachestvenno novykh svoistv. V svyazi s etim voznikaet teoreticheskaya zadacha o mikroskopicheskoi strukture i svoistvakh takogo sverkhprovodyashchego sostoyaniya, chemu i posvyashchena nastoyashchaya rabota.
Predlozheny dve vozmozhnye mikroskopicheskie struktury takogo sostoyaniya: (1) kogda parametr poryadka VSP imeet solitonnuyu strukturu i (2) kogda VSP ne privodit k obrazovaniyu shcheli na vsei poverkhnosti Fermi (t.e. kogda uslovie nestinga ne vypolnyaetsya na vsei poverkhnosti Fermi). Pokazano, chto v oboikh stsenariyakh prisutstvie volny spinovoi plotnosti podavlyaet singletnoe sparivanie, i chto vblizi zarozhdeniya sverkhprovodimost’ dolzhna imet’ tripletnoe sparivanie [L.P. Gorkov, P.D. Grigoriev, «Nature of superconducting state in the new phase in (TMTSF)2PF6 under pressure», Phys. Rev. B 75, 020507 (2007)]. Volna zaryadovoi plotnosti ne privodit k takomu effektu.
Issledovany svoistva sverkhprovodyashchego sostoyaniya, sosushchestvuyushchego s volnoi zaryadovoi ili spinovoi plotnosti [P. Grigoriev, submitted to Phys. Rev. B]. Vychisleno verkhnee kriticheskoe pole Hc2 i pokazano, chto (1) v oboikh stsenariyakh ono v neskol’ko raz vozrastaet vblizi kriticheskogo davleniya, gde sverkhprovodimost’ tol’ko poyavlyaetsya, i (2) v solitonnom stsenarii temperaturnaya zavisimost’ Hc2 dazhe dlya polya, perpendikulyarnogo provodyashchim sloyam, imeet sil’nyi zagib vverkh (polozhitel’nuyu vtoruyu proizvodnuyu). Obe eti cherty povedeniya Hc2 yavlyayutsya neobychnymi, no soglasuyutsya s eksperimentom.

Obshchaya teoriya konkurentsii

14 December 2007 in 11:30

B.A. Trubnikov

Theory of the reentrant effect in mesoscopic NS samples (effect A.C. Mota)

7 December 2007 in 11:30

G.A. Gogadze (FTINT NAN Ukrainy, Khar’kov)

Nami ob’yasnena priroda reentrant effekta, kotoraya sushchestvenno opiraetsya na svoistva urovnei Andreeva v NS strukture.

Teoriya izmerenii i interpretatsiya kvantovoi mekhaniki

30 November 2007 in 11:30

G.B. Lesovik

My obsudim protsess odnokratnykh i povtornykh izmerenii s tochki zreniya kvantovoi mekhaniki. My takzhe obsudim ogranicheniya na vozmozhnost’ postroeniya deterministicheskoi kvantovoi mekhaniki, v kotoroi rezul’taty izmerenii mogut byt’ odnoznachno predskazany.

Plastic response of metals and semiconductors to irradiation by short laser pulse

30 November 2007 in 11:30

N.A. Inogamov

Patch coalescence as a mechanism for eukaryotic directional sensing, Phys. Rev. Lett., 99, 158101 (2007)

23 November 2007 in 11:30

A. Gamba, I. Kolokolov, V. Lebedev, and G. Ortenzi (dokladchik - V.V. Lebedev)

Kletki-eukarioty imeyut chuvstvitel’nyi khimicheskii kompas, pozvolyayushchii im orientirovat’sya (i zatem dvigat’sya) v napravlenii istochnika rastvorennogo khimicheski aktivnogo veshchestva. Vnekletochnyi khimicheskii signal vklyuchaet razdelenie kletochnoi membrany na dve oblasti, naselennye raznymi fosfolipidami i orientirovannymi vdol’ anizotropii signala. V dannoi rabote postroena teoriya protsessa polyarizatsii (imenno, ego kinetiki). Vremennaya kartina vklyuchaet v sebya nukleatsiyu, rost oblastei novoi fazy vnutri prezhnei i sliyaniya etikh oblastei v odno orientirovannoe pyatno. Rezul’tatami raboty yavlyayutsya, v chastnosti, proportsional’nost’ vremeni polyarizatsii kletki obratnomu kvadratu anizotropii vneshnego khimicheskogo signala i porogovoe znachenie etoi anizotropii, pri kotorom ona eshche vliyaet na polyarizatsiyu kletki kak obratnyi razmer kletki. Poslednee pozvolyaet ob’yasnit’, pochemu opredelyat’ napravlenie v storonu istochnika mogut lish’ otnositel’no bol’shie po razmeram kletki-eukarioty.

Nizkoporogovaya lazernaya generatsiya v kiral’nykh zhidkikh kristallakh

9 November 2007 in 11:30

V.A. Belyakov

O dissipatsii v potentsial’nom techenii zhidkosti so svobodnoi granitsei

2 November 2007 in 11:30

A.I. D’yachenko

Using linear approximation to the Navier-Stokes equation we derived equations for potential flow which include dissipation due to viscosity. We derive viscous correction not only to the irrotational pressure, but to the kinematic boundary condition also.

Adiabatic quantum pumping in interacting systems

26 October 2007 in 11:30

Alessandro Silva (ICTP)

Adiabatic quantum pumping in noninteracting, phase coherent systems is elegantly described by Brouwer's formula. The latter expresses geometrically the charge pumped per cycle in terms of the scattering matrices. Interactions within the dot, while suppressing phase coherence, make Brouwer's formalism inapplicable. In the presence of interactions, is a geometric description of pumping still possible ? And what are the new, important physical processes brought in by the presence of interaction ? In this talk, I will discuss recent work focusing on giving an answer to these questions. In particular, I will discuss the interaction corrections to Brouwer's formula and show that they are related to inelastic scattering events. As an illustrative example to discuss the role of inelasticity in pumping I will consider the effect of interaction with a bosonic bath on a resonant level quantum pump. Finally, if time will allow, I will describe the exact solution of the problem of pumping in quantum dots in the Kondo regime (at the Toulouse point).

Exact N-particle scattering matrix for electrons interacting on a quantum dot

26 October 2007 in 11:30

A.V. Lebedev

We derive an exact formula for the scattering matrix for N particles interacting within a quantum dot. Characterizing the dot by its resonances, we find a compact form for the scattering matrix in a real-time representation. We make use of our results to study the transmission probabilities and interaction-induced orbital entanglement of two electrons incident on the dot in a spin-singlet state.

Rezhimy dinamiki vezikuly vo vneshnem potoke»

19 October 2007 in 11:30

S.S. Vergeles

Vezikula, pomeshchyonnaya vo vneshnii potok, mozhet kuvyrkat’sya, pokachivat’sya i sokhranyat’ svoyu orientatsiyu s techeniem vremeni, chto sootvetstvuet razlichnym dinamicheskim rezhimam. My poluchili uravnenie, opisyvayushchuyu dinamiku vezikul po forme blizkikh k sfericheskoi, analiz kotorogo pozvolil nam postroit’ fazovuyu diagrammu, predskazyvayushchuyu realizatsiyu togo ili inogo dinamicheskogo rezhima. Diagramma risuetsya v ploskosti dvukh bezrazmernykh parametrov, kotorye zavisyat ot izbytochnoi ploshchadi vezikuly, vyazkostei zhidkostei vnutri i snaruzhi vezikuly, vyazkosti i modulya uprugosti membrany, sily vneshnego potoka i, nakonets, otnosheniya vrashchatel’noi i rastyagivayushei komponenty vneshnego potoka. Ustanovleno, chto perekhod iz rezhima parallel’nogo perenosa v rezhim pokachivaniya proiskhodit cherez bifurkatsiyu Khopfa, togoda kak perekhod iz rezhima parallel’nogo perenosa v rezhim kuvyrkaniya proiskhodit cherez bifurkatsiyu tipa saddle-node. Ustanovleno kriticheskoe zamedlenie vblizi soedineniya linii perekhodov. Nakonets, obnaruzhen novyi rezhim kolebaniya vezikuly, kotoryi my nazvali krucheniem.

Isochronous systems are not rare

12 October 2007 in 11:30

Francesco Calogero Physics Department, University of Rome I La Sapienza Istituto Nazionale di Fisica Nucleare, Sezione di Roma

A (classical) dynamical system is called isochronous if it features an open (hence fully dimensional) region in its phase space in which all its solutions are completely periodic (i. e., periodic in all degrees of freedom) with the same fixed period (independent of the initial data, provided they are inside the isochrony region). When the isochrony region coincides with the entire phase-space one talks of entirely isochronous systems. A trick is presented associating to a dynamical system a modified system depending on a parameter so that when this parameter vanishes the original system is reproduced while when this parameter is positive the modified system is isochronous. This technique is applicable to large classes of dynamical systems, justifying the title of this talk. An analogous technique, even more widely applicable - for instance, to any translation-invariant (classical) many-body problem transforms a real autonomous Hamiltonian system into an entirely isochronous real autonomous Hamiltonian system. The modified system is of course no more translation-invariant, but in its center-of-mass frame it generally behaves quite similarly to the original system, over times much shorter than the isochrony period T (which may be chosen at will). Hence, when this technique is applied to a realistic many-body Hamiltonian yielding, in its center of mass frame, chaotic motions with a natural time-scale much smaller than (the chosen) T, the corresponding modified Hamiltonian shall yield a chaotic behavior (implying statistical mechanics, thermodynamics with its second principle, etc.) for quite some time before the entirely isochronous character of the motion takes over hence the system returns to its initial state, to repeat the cycle over and over again. We moreover show that the quantized versions of these modified Hamiltonians feature infinitely degenerate equispaced spectra. Analogous techniques are applicable to nonlinear evolution PDEs, but in this talk there will be no time to cover this aspect. The material presented is a synthesis of work done over the last 10 years with several collaborators, as reviewed in a 240-page monograph entitled Isochronous systems, now in press by Oxford University Press (scheduled to appear in February 2008).

Nelineinaya stadiya neustoichivosti Bendzhamina-Feira: trekhmernye kogerentnye struktury i gigantskie volny»

5 October 2007 in 11:30

V.P. Ruban

S pomoshch’yu chislennykh eksperimentov raspoznan spetsificheskii trekhmernyi mekhanizm formirovaniya gigantskikh voln na glubokoi vode, kotoryi deistvuet na nelineinoi stadii modulyatsionnoi neustoichivosti ploskoi begushchei volny. Grafik volnovoi ogibayushchei spontanno obrazuet uzor iz polos zigzagoobraznoi formy. Pri dostatochno bol’shoi nachal’noi krutizne volny ($ka>0.06$) eti kogerentnye struktury proizvodyat gigatskie volny. Naibolee vysokie volny voznikayut v uglakh zigzagov. Pri $ka

Energeticheskaya relaksatsiya v neuporyadochennoi elektronnoi zhidkosti

28 September 2007 in 11:30

N.M. Shchelkachev

Kiral’nye monopoli v kvantovoi khromodinamike

21 September 2007 in 11:30

M.N. Chernodub (ITEF, Moskva)

Predstavlen novyi topologicheskii kalibrovochno-invariantnyi ob’ekt v KKhD, «kiral’nyi monopol’», kotoryi kharakterizuetsya sokhranyayushchimsya magnitnym zaryadom i opredelyaetsya s pomoshch’yu sobstvennykh funktsii operatora Diraka v glyuonnykh polyakh. Kiral’nyi monopol’ pokhozh na monopol’ Nambu v elektroslaboi teorii i imeet analog v zhidkom gelii (He3-A). Rassmatrivaemyi ob’ekt razrushaet kiral’nyi i khromomagnitnye kondensaty v svoei serdtsevine. S pomoshch’yu chislennogo modelirovaniya teorii Yanga-Millsa prodemonstrirovano zametnoe uvelichenie plotnosti takikh monopolei pri temperaturnom perekhode «adronnaya faza»-«glyuonnaya plazma», chto soglasuetsya s vosstanovleniem kiral’noi simmetrii pri vysokoi temperature.

Opticheskie svoistva dopirovannykh grafenovykh sloev

14 September 2007 in 11:30

L.A. Fal’kovskii

Vychislen koeffitsient otrazheniya v infrakrasnoi oblasti ot grafenovogo monosloya, a takzhe ot sistemy sloev. Ispol’zuetsya kvantovoe vyrazhenie dlya provodimosti, zavisyashchei ot chastoty, temperatury i kontsentratsii nositelei v bezstolknovitel’nom rezhime. V okrestnosti poroga elektronnogo mezhzonnogo pogloshcheniya v sisteme sloev vozmozhno vozbuzhdenie plazmonov, blagodarya chemu koeffitsient otrazheniya pri nizkikh temperaturakh obnaruzhivaet rezkoe padenie, soprovozhdaemoe uzkim minimumom.

Ubyvayushchee yadro Koshi dlya diskretizatsii komleksnogo analiza Dynnikova-Novikova na treugol’noi reshetke

14 September 2007 in 11:30

P.G. Grinevich, R.G. Novikov (korotkii doklad)

V rabotakh S.P. Novikova i I.A. Dynnikova byla predlozhena novaya diskretizatsiya operatorov ∂, ∂ i operatora Laplasa na treugol’noi reshetke. Kak izvestno, v standartnoi diskretizatsii na kvadratnoi reshetke pervye dva operatora opredeleny na vsei reshetke, a Laplas estestvenno redutsiruetsya na chetnuyu podreshetku. V sluchae Dynnikova-Novikova vse tri operatora zhivut na odnoi reshetke, chto bolee estestvenno s algebraicheskoi tochki zreniya. Klyuchevuyu rol’ v kompleksnom analize igraet formula Koshi. Dlya nakhozhdeniya ee diskretnogo analoga neobkhodimo postroit’ ubyvayushchuyu na beskonechnosti funktsiyu Grina operatora ∂. Eta zadacha byla postavlena v rabotakh S.P. Novikova i I.A. Dynnikova. My privodim ee reshenie.

Gipoteza Littlvuda

7 September 2007 in 11:30

Ya.G. Sinai

Gipoteza Littlvuda - izvestnaya problema teorii chisel. Soglasno etoi gipoteze dlya lyubykh dvukh irratsional’nykh chisel α1 i α2 naidetsya takaya posledovatel’nost’ tselykh chisel ni, dlya kotoroi ni {niα1} {niα2} stremitsya k nulyu pri stremlenii i k beskonechnosti. Trudnost’ problemy v tom, chto takie ni ochen’ redki i "sluchainy". Novyi podkhod k probleme osnovan na teorii dinamicheskikh sistem.

Symmetry constraints on phonon dispersion in graphene

15 June 2007 in 11:30

L. Falkovsky

Taking into account constraints imposed by the lattice symmetry, the phonon dispersion is calculated for graphene with interactions between first and second nearest neighbors. We show that only five force constants give a very good fitting to elastic constants and Raman frequencies observed in graphite.

Matrichnye uravneniya gidrodinamicheskogo tipa kak reduktsii sistem integriruemykh metodom obratnoi zadachi rasseyaniya

8 June 2007 in 11:30

A. Zenchuk

Teoriya vozmushchenii v dinamike solitonov

25 May 2007 in 11:30

K.A. Gorshkov (IPF, Nizhnii Novgorod)

Utverzhdenie otzyva vedushchei organizatsii na doktorskuyu dissertatsiyu Gorshkova K.A. (IPF, Nizhnii Novgorod)

25 May 2007 in 11:30

Uedinyonnye volny v plazmonnykh Breggovskikh reshyotkakh

18 May 2007 in 11:30

A.O. Korotkevich

V rabote izucheno rasprostranenie sveta v Breggovskoi periodicheskoi strukture soderzhashchei tonkie plyonki s metallicheskimi nanochastitsami. Chastoty plazmonnogo rezonansa, Breggovskogo rezonansa i opticheskoi nesushchei volny predpolagayutsya blizkimi. Naideny i izucheny tochnye resheniya opisyvayushchie uedinyonnye volny v dannoi sisteme. Takzhe rassmotreno yavlenie ostanovki sveta vsledstvie angarmonichnosti vlazmonnykh ostsillyatsii.

Dynamics of wrinkles on a vesicle in external flow

11 May 2007 in 11:30

K. Turitsyn, S. Vergeles

Recent experiments by Kantsler et. al. (2007) have shown that the relaxational dynamics of a vesicle in external elongation flow is accompanied by the formation of wrinkles on a membrane. Motivated by these experiments we present a theory describing the dynamics of wrinkling membrane. Formation of wrinkles is related to the dynamical instability induced by negative surface tension of the membrane. For quasi-spherical vesicles we perform analytical study of the wrinkle structure dynamics. We derive the expression for the instability threshold and identify three stages of the dynamics. The scaling laws for the temporal evolution of wrinkling wavelength and surface tension are established and confirmed numerically.

Dual’nost’ sverkhprovodnik izolyator v setke iz dozefsonovskikh provolochek

4 May 2007 in 11:30

I. Protopopov, M. Feigel’man

My predlagaem novuyu model’nuyu sistemu dlya izucheniya perekhoda sverkhprovodnik — izolyator. Eta sitema predstavlyaet soboi regulyarnuyu reshetku, kazhdoe rebro kotoroi sostoit iz N ≫ 1 dzhozefsonovskikh kontaktov, soedinennykh posledovatel’no. Dlya sluchaya, kogda dzhozefsonovskaya energiya kontaktov velika po sravneniyu s zaryadovoi, razvita teoriya, opisyvayushchaya takuyu setku. Vyvedeno tochnoe dual’noe preobrazovanie, perevodyashchee gamil’tonian iskhodnoi sistemy v standartnyi gamil’tonian dzhozefsonovskoi setki na kvadratnoi reshetke. Dlya magnitnykh frustratsii f = 0 i f = 1/2 naideno kriticheskoe otnoshenie EJ/EC, pri kotorom v rassmatrivaemoi sisteme proiskhodit nul’temperaturnyi perekhod sverkhprovodnik-izolyatorm i opredelena zavisimot’ temperatury sverkhprovodyashchego perekhoda ot EJ/EC. Analogichnye velichiny otseneny dlya sluchaya nulevoi magnitnoi frustratsii no v prisutstvii sil’noi sluchainoi zaryadovoi frustratsii.

New features of the Abramovsky-Gribov-Kancheli unitarity rules in QCD

27 April 2007 in 11:30

N. Nikolaev, W. Schaefer

Based on the nonlinear k-factorization approach to hard pQCD in a nuclear environment, we derive a relationship between the multipomeron exchmnage contributions to the total, diffractive and inelastic topological cross sections. We show how the non-Abelian intranuclear evolution of color dipoles entails an existence of two kinds of the unitarity-cvut pomerons. The cutting rules suggested in 1973 by Abramovsky, Gribov and Kancheli are shown to be dramatically violated in QCD.

Bootstrap in Supersymmetric Liouville Field Theory

20 April 2007 in 11:30

Alexander Belavin

Super-Liouville theory is important for its relation to Non-Critical Superstring theory. The 4-point correlation function of exponential fields is constructed in the N=1 Super-Liouville field theory. This construction involves the so-called Conformal Blocks, for which we suggest a recursion representation. Together with the explicit expression for Structure constants of Operator Product Expension(OPE) it allows to construct the 4-point function and to verify that the OPE algebra of LFT is associative.

Ob izmerenii korrelyatorov toka vysshikh poryadkov

13 April 2007 in 11:30

K.V. Bayandin, A.V. Lebedev, G.B. Lesovik

V rabote rassmatrivaetsya vopros ob izmerimosti fluktuatsii toka vysshikh poryadkov lineinym detektorom. Rassmotreny dva razlichnykh tipa izmerenii: izmerenie spektral’noi moshchnosti fluktuatsii i izmerenie raznovremennykh korrelyatorov toka pri fiksirovannykh vremenakh. Dlya kazhdogo sluchaya polucheny formal’no tochnye vyrazheniya dlya pokazanii detektora, soderzhashchie uporyadochennye vdol’ Keldyshevskogo kontura operatory elektronnogo toka. Naiden yavnyi vid vremennogo uporyadocheniya operatorov toka pod znakom srednego pri izmerenii raznovremennykh korrelyatorov toka vysshikh poryadkov. Rassmotrena situatsiya, kogda detektor izmeryaet korrelyatsii toka v razlichnykh tochkakh provodnika.

Vychislitel’nyi klaster ITF «PARMA»

6 April 2007 in 11:30

M. Medvedeva

Osnovnye kharakteristiki i pravila ispol’zovaniya. Kratkoe soobshchenie, 5–10 minut.

Minimal’naya provodimost’ v neuporyadochennom grafene

6 April 2007 in 11:30

P.M. Ostrovskii, I.V. Gornyi, A.D. Mirlin

Izucheny transportnye svoistva monoatomnogo sloya grafita (grafena) s razlichnymi tipami besporyadka pri polovinnom zapolnenii. Pokazano, chto provodimost’ sistemy sushchestvenno zavisit ot simmetrii besporyadka. Predskazano otsutstvie lokalizatsii, esli besporyadok ne narushaet odnu iz kiral’nykh simmetrii chistoi sistemy ili ne peremeshivaet doliny. V sluchae kiral’nogo besporyadka naideno tochnoe znachenie minimal’noi provodimosti 4e2/π h. Dlya sluchaya plavnogo besporyadka vyvedena effektivnaya teoriya polya (sigma-model’). Esli plavnyi besporyadok ne narushaet simmetriyu otnositel’no obrashcheniya vremeni, sigma-model’ prinadlezhit simplekticheskomu klassu s topologicheskim chlenom θ=π. V takoi modeli predskazana ustoichivaya kriticheskaya tochka s provodimost’yu poryadka e2/h. Esli effektivnaya simmetriya otnositel’no obrashcheniya vremeni narushena, to sigma-model’ stanovitsya unitarnoi. Pri etom minimal’naya provodimost’ sovpadaet s kriticheskoi provodimost’yu dlya kvantovokholl’nogo perekhoda ~2e2/h.

Theory of resonant multiphonon Raman scattering in graphene

30 March 2007 in 11:30

D.M. Basko (Columbia University)

The Raman spectrum of graphene consists of distinct narrow peaks corresponding to different optical phonon branches as well as their overtones. In this work it is shown how the relative intensities of the overtone peaks encode information about relative strengths of different inelastic scattering processes electrons are subject to. In particular, under the assumption that the most important inelastic processes are electron-phonon and electron-electron scattering, one can deduce their relative interaction strengths from the Raman spectra. On the road to this result we encounter, surprisingly, not only dull calculations of the Raman cross-sections, but also some interesting technical points which bring our thoughts back to some fundamental issues such as Furry’s theorem in quantum electrodynamics, quasiclassical approximation, and its relation to quantum kinetic equation, viewed at a somewhat different (and unexpected) angle. These general physical aspects are going to be the main focus of the talk, but an introduction to specific features of electron-phonon physics in graphene will also be given.

Interferentsiya neadiabaticheskikh perekhodov v sverkhprovodnikovom kubite

23 March 2007 in 11:30

Yurii Makhlin

Izuchayutsya kogerentnye perekhody mezhdu peresekayushchimisya urovnyami v sverkhprovodnikovom kubite. V sluchae posledovatel’nosti takikh perekhodov voznikaet interferentsiya, t.k. zaselennosti urovnei chuvstvitel’ny k fazam, nabrannym mezhdu perekhodami i v rezul’tate perekhodov. Obsuzhdayutsya nablyudaemye v eksperimente interferentsionnye kartiny i vliyanie shuma.

Provodimost’ kontakta normal’nyi metall-sverkhprovodnik v faze Berezinskogo

16 March 2007 in 11:30

Ya.V. Fominov, M.V. Feigel’man

V 1974 godu Berezinskii zametil, chto v He3 teoreticheski vozmozhna s-volnovaya spin-tripletnaya faza. Fermionnaya antisimmetriya budet vypolnena, esli anomal’naya funktsiya Grina nechetna po energii (otnositel’no urovnya Fermi). Odnako eksperimental’no takaya vozmozhnost’ v He3 po-vidimomu ne realizuetsya. V 2001 godu Bergeretom, Volkovym i Efetovym bylo pokazano, chto faza Berezinskogo dolzhna voznikat’ v sisteme obyknovennyi sverkhprovodnik — neodnorodnyi ferromagnetik v rezul’tate effekta blizosti. Krome togo, imeyutsya eksperimental’nye ukazaniya na vozmozhnost’ sushchestvovaniya sverkhprovodimosti Berezinskogo v soedinenii Na_x Co O_2 * y H_2 0. My predlagaem eksperiment, kotoryi mozhet otlichit’ sverkhprovodimost’ Berezinskogo ot obychnoi chetnoi po energii sverkhprovodimosti. Klyuchevuyu rol’ v provodimosti kontakta normal’nyi metall-sverkhprovodnik pri malykh napryazheniyakh igraet andreevskoe otrazhenie. Andreevskoe otrazhenie «svyazyvaet» mezhdu soboi polozhitel’nuyu i otritsatel’nuyu energii, i poetomu chuvstvitel’no k simmetrii po energii.

Mezoskopicheskie fluktuatsii dzhozefsonovskogo toka v duffuznykh SNS kontaktakh

9 March 2007 in 11:30

M.A. Skvortsov

Issledovany mezoskopicheskie fluktuatsii sverkhtekuchego toka v dzhozofsonovskikh kontaktakh cherez normal’nyi metall s diffuznoi elektronnoi dinamikoi. S pomoshch’yu nelineinoi replichnoi sigma-modeli zadacha svedena k vychisleniyu fluktuatsionnogo determinanta na fone prostranstvenno neodnorodnogo effekta blizosti v normal’noi oblasti. Mezoskopicheskie fluktuatsii i slabolokalizatsonnaya popravka k sverkhtekuchemu toku naideny pri proizvol’nom sootnoshenii mezhdu sverkhprovodyashchei shchel’yu i energiei Taulessa. V sluchae dlinnogo SNS kontakta mezoskopicheskie fluktuatsii v neskol’ko raz prevyshayut staryi rezul’tat Al’tshulera i Spivaka.

Kulonovskaya blokada i super universal’nost’ teta-ugla

2 March 2007 in 11:30

I.S. Burmistrov, A.M.M. Pruisken (ITFA, Amsterdam)

V rabote rassmotrena model’ Ambegaokara-Ekkerna-Shona, opisyvayushchaya yavlenie kulonovskoi blokady v odno-elektronnom tranzistore. Predlozhena novaya fizicheskaya «nablyudaemaya», kotoraya v otlichie ot srednego zaryada na ostrovke odno-elektronnogo tranzistora, tselochislenno kvantuetsya pri nule temperatur, nezavisimo ot znachenii kondaktansov tunel’nykh kontaktov. Eta novaya fizicheskaya «nablyudaemaya» analogichna Khollovskoi provodimosti v kvantovom effekte Kholla.

Neravnovesnyi perenos zaryada a dlinnykh odnokanal’nykh kontaktakh sverkhprovodnik-normal’nyi metall-sverkhprovodnik

16 February 2007 in 11:30

N.B. Kopnin, J. Voutilainen

Vychislyaetsya postoyannyi tok cherez dlinnyi odnokanal’nyi kontakt sverkhprovodnik-normal’nyi metall-sverkhprovodnik v prisutstvii slabogo napryazheniya, sozdayushchego perekhody Landau-Zenera mezhdu andreevskimi urovnyami. Pri bol’shom chisle urovnei v kontakte neravnovesnost’, sozdavaemvya perekhodami, usilivaetsya i privodit k znachitel’nomu rostu postoyannogo toka.

"Integriruemost’ matrichnykh uravnenii gidrodinamicheskogo tipa"

9 February 2007 in 11:30

A.I. Zenchuk

Rassmotren klass matrichnykh uravnenii gidrodinamicheskogo tipa proizvol’noi razmernosti, k kotorym primenim metod kharakteristik postroeniya reshenii. Zadacha svoditsya k resheniyu matrichnogo algebraicheskogo uravneniya ili sistemy uravnenii. Rassmotreny reduktsii, umen’shayushchie chislo zavisimykh peremennykh. Predlagaetsya obobshchenie metoda na nelineinye uravneniya vtorogo poryadka.

"Nonlinear theory of mirror instability of plasmas with pressure anisotropy"

2 February 2007 in 11:30

E.A. Kuznetsov

"Rentgenospektral’naya diagnostika korotkozhivushchei plazmy."

26 January 2007 in 11:30

I.Yu. Skobelev (ITES OIVT RAN)

Rassmatrivaetsya ispol’zovanie metodov i sredstv vysokorazreshayushchei rentgenovskoi spektroskopii dlya diagnostiki korotkozhivushchei plazmy, poluchaemoi pri nagreve razlichnogo tipa mishenei (tverdotel’nye, klasternye) intensivnymi lazernymi impul’sami femto- i pikosekundnoi dlitel’nosti ili pri vozdeistvii na kondensirovannye sredy puchkov tyazhelykh ionov vysokoi energii. Dana interpretatsiya eksperimental’nykh rezul’tatov, poluchennykh v poslednee vremya sovmestno s razlichnymi rossiiskimi i zarubezhnymi issledovatel’skimi tsentrami.

"Kinetika elektronov v neuporyadochennoi elektronnoi sisteme"

19 January 2007 in 11:30

N.M. Shchelkachev, I.S. Burmistrov

"Integrirovanie novykh klassov mnogomernykh nelineinykh uravnenii v chastnykh proizvodnykh pervogo poryadka metodom odevaniya"

12 January 2007 in 11:30

A.I. Zenchuk

Predlozhena novaya versiya metoda odevaniya osnovannaya na lineinom integral’nom uravnenii s netrivial’nym yadrom integral’nogo operatora, pozvolyayushchaya vyyavit’ novyi klass chastichno integriruemykh uravnenii v chastnykh proizvodnykh proizvol’noi razmernosti. V kachestve primera rassmotreny uravneniya pervogo poryadka s kvadratichnoi nelineinost’yu.

"Chislennaya proverka kineticheskogo uravneniya dlya voln Khassel’manna: vliyanie dissipativnogo chlena"

12 January 2007 in 11:30

A.O. Korotkevich

"Korrelyatsionnye funktsii v integriruemoi teorii polya"

29 December 2006 in 11:30

Zashchita kandidatskoi dissertatsii A.V. Litvinova

Zasedanie Uchenogo soveta ITF

29 December 2006 in 11:30

1. Itogi ukhodyashchego goda. Vystuplenie direktora
2. Predstavlenie k zashchite doktorskoi dissertatsii Gukova S.G.
3. Utverzhdenie kandidatskikh dissertatsii Saptsova R.B., Turitsyna K.S. i Protopopova I.V.
4. Utverzhdenie otzyva vedushchei organizatsii na dissertatsiyu Zmeeva D.E.
5. Obsuzhdenie plana meropriyatii po prazdnovaniyu 100 let L.D. Landau
6. Golosovanie po personal’nym voprosam.

Dirakovskie fermiony v grafite

22 December 2006 in 11:30

I. Luk’yanchuk

"Vynuzhdennoe rasseyanie Mandel’shtamma-Brillyuena nazad dlya chastichno kogerentnogo lazernogo puchka v vysokotemperaturnoi plazme"

22 December 2006 in 11:30

Pavel Lushnikov

"Integrirovanie novykh klassov mnogomernykh nelineinykh uravnenii v chastnykh proizvodnykh pervogo poryadka metodom odevaniya"

22 December 2006 in 11:30

Aleksandr Zenchuk

Predlozhena novaya versiya metoda odevaniya osnovannaya na lineinom integral’nom uravnenii s netrivial’nym yadrom integral’nogo operatora, pozvolyayushchaya vyyavit’ novyi klass chastichno integriruemykh uravnenii v chastnykh proizvodnykh proizvol’noi razmernosti. V kachestve primera rassmotreny uravneniya pervogo poryadka s kvadratichnoi nelineinost’yu.

Magnetoresistance of the normal metal-superconductor interface

15 December 2006 in 11:30

N.M. Chtchelkatchev, I.S. Burmistrov, I. Batov

Zaputannost’ po energii v gibridnykh sverkhprovodyashchikh strukturakh

15 December 2006 in 11:30

K.V. Bayandin, G.B. Lesovik, T. Martin

V rabote prodemonstrirovana zaputannost’ po energii dlya sostoyaniya dvukh elektronov, obrazuyushchikhsya pri raspade Kuperovskoi pary v normal’nyi provodnik. Privedeno neposredstvennoe vychislenie matritsy plotnosti etogo sostoyaniya i pokazano, chto ono deistvitel’no zaputano. Predlozhena skhema eksperimenta, v kotoroi mozhno provesti test Bella dlya korrelyatsii elektricheskikh tokov i dokazat’ nalichie zaputannosti eksperimental’no. Obsuzhdayutsya parametry ustanovki, pri kotorykh proiskhodit narushenie neravenstv Bella, a takzhe sravnivayutsya rezul’taty, poluchennye dvumya raznymi sposobami: vychisleniem matritsy plotnosti i proverkoi neravenstva Bella.

Drobnyi zaryad v andreevskikh kvantovykh tochkakh

15 December 2006 in 11:30

I.A. Sadovskii, G.B. Lesovik, G. Blatter

Pokazano chto kvantovaya tochka, prisoedinennaya k sverkhprovodyashchim beregam, neset v sebe drobnyi zaryad. On poyavlyaetsya iz-za narusheniya elektronno-dyrochnoi simmetrii i mozhet nepreryvno izmenyatsya s pomoshch’yu izmeneniya potentsiala zatvora, ili raznitsy mezhdu fazami sverkhprovodnikov. Opredelen zaryad osnovnogo sostoyaniya, ravnovesnyi zaryad i zaryad vozbuzhdeniya. Obsuzhdayutsya kvantovye i termodinamicheskie fluktuatsii zaryada i kulonovskoe vzaimodeistvie.

"Sosushchestvovanie sverkhprovodimosti i volny spinovoi plotnosti v organicheskom metalle (TMTSF)2PF6"

8 December 2006 in 11:30

P.D. Grigor’ev

The unusual phase has been recently observed in the organic material (TMTSF)_{2}PF_{6}, where superconductivity (SC) coexists with spin-density wave (SDW) in the pressure interval p_{c1}

Effects of Exchange Symmetry on Full Counting Statistics

8 December 2006 in 11:30

G.B. Lesovik, F. Hassler, G. Blatter

We study the full counting statistics for the transmission of two identical particles with positive or negative symmetry under exchange for the situation where the scattering depends on energy. We find that, besides the expected sensitivity of the noise and higher cumulants, the exchange symmetry has a huge effect on the average transmitted charge: for equal spin exchange-collelated electrons the average transmitted charge can be orders of magnitude larger than the corresponding value for the independent electrons. A similar, although smaller, effect is found in a four lead geometry even for energy-independent scattering.

Rezul’taty chislennykh eksperimentov po poverkhnostnym volnam

1 December 2006 in 11:30

V.E. Zakharov

O parakh kommutiruyushchikh gamil’tonianov, kvadratichnykh po impul’sam

24 November 2006 in 11:30

V.V. Sokolov, V.G. Marikhin

Obsuzhdaetsya zadacha klassifikatsii takikh par v sluchae dvukh stepenei svobody. Privoditsya obshchaya formula dlya funktsii deistviya.

"Dal’nodeistvuyushchaya nechetnaya tripletnaya sverkhprovodimost’ v sistemakh sverkhprovodnik-ferromagnetik s neelevskoi domennoi strukturoi"

17 November 2006 in 11:30

Ya.V. Fominov, A.F. Volkov, K.B. Efetov

Rassmotren kontakt singletnyi sverkhprovodnik - ferromagnetik (SF) s neelevskoi domennoi strukturoi v F chasti. Pokazano, chto vblizi domennykh stenok proiskhodit generatsiya "dal’nodeistvuyushchei" tripletnoi sverkhprovodyashchei komponenty (nechetnoi po energii), kotoraya pronikaet vglub’ domenov na rasstoyanie poryadka \xi_T = \sqrt{D / 2 \pi T} (rassmatrivaetsya gryaznyi predel, D - koeffitsient diffuzii). Eta dlina gorazdo bol’she, chem obychnaya "korotkodeistvuyushchaya" dlina \xi_h = \sqrt{D / h} (gde h - obmennaya energiya), kharakterizuyushchaya glubinu proniknoveniya sverkhprovodimosti v monodomennyi ferromagnetik. Vychislena popravka k plotnosti sostoyanii v ferromagnetike blagodarya dal’nodeistvuyushchei tripletnoi komponente i obuslovlennyi eyu dzhozefsonovskii tok v SFS kontakte.

Averaging in Spherically Symmetric Cosmology

10 November 2006 in 11:30

A.A. Coley Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia

We discuss the averaging problem in general relativity using the form of the macroscopic gravity equations in the case of spherical symmetry in volume preserving coordinates. In particular, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. On cosmological scales, the correlation tensor in a Friedmann-Lematre-Robertson-Walker background is found to be of the form of a spatial curvature. On astrophysical scales the correlation tensor can be interpreted as the sum of a spatial curvature and an anisotropic fluid. We briefly discuss the physical implications of these results.

Infinitezimal’l’nye preobrazovaniya Darbu i spektral’nye krivye torov v 4-kh mernom prostranstve

3 November 2006 in 11:30

Pyotr Grinevich (sovmestnaya rabota s Iskanderom Taimanovym)

Nami pokazano, chto spektral’naya krivaya operatora Diraka, zadayushchego vlozhenie tora v 4-kh mernoe prostranstvo invariantna otnositel’no konformnykh preobrazovanii. Etot rezul’tat obobshchaet moi rezul’tat sovmestno s Martin Schmidt pro vlozheniya torov v 3-kh mernoe prostranstvo i invariantnost’ vysshikh funktsionalov Uilmora.

Gigantskoe usilenie teploprovodnosti vdol’ vikhrya v mezoskopicheskom sverkhprovodnike

27 October 2006 in 11:30

N. Kopnin

Pokazano, chto chislo poperechnykh provodyashchikh mod v kore vikhrya, nakhodyashchegosya v mezoskopicheskom sverkhprovodyashchem tsilindre, znachitel’no prevoskhodit chislo mod v vikhre v massivnom obraztse. Eto proiskhodit v blagodarya mezoskopicheskim ostsillyatsiyam urovnei energii v obraztsakh konechnykh razmerov i privodit k gigantskomu uvelicheniyu teploprovodnosti vdol’ napravleniya magnitnogo polya.

Povedenie vezikul vo vneshnem pole skorosti

20 October 2006 in 11:30

V.V. Lebedev, S.K. Turitsyn, S.S. Vergeles

Statistics of entropy generated by a gradient flow over polymer

13 October 2006 in 11:30

K. Turitsyn

We consider a wide class of linear stochastic problems driven off the equilibrium by a multiplicative assymetric force. The force brakes detailed balance, the system otherwise maintains, thus producing entropy. Large deviation function of the entropy production in the system is calculated explicitly. The general result is illustrated on example of a polymer immersed in a gradient flow and subjected to thermal fluctuations.

Soobshchenie o konferentsii po grafenu v Drezdene

6 October 2006 in 11:30

M.A. Skvortsov

Ob odnom klasse giperbolicheskikh sistem

29 September 2006 in 11:30

V.E. Adler, A.B. Shabat

Obobshchennye modeli Godena. Nelokal’nye integraly dvizheniya

22 September 2006 in 11:30

B.L. Feigin

Vysshie uravneniya dvizheniya v N = 1 supersimmetrichnom Liuville

15 September 2006 in 11:30

A.A. Belavin

Ob eksponentsial’noi lokalizatsii na reshetke Gabora-fon Neimana, a takzhe nekotorykh drugikh rezul’tatakh

8 September 2006 in 11:30

G.T. Avanesyan (IPKhF)

Zasedanie dissertatsionnogo soveta ITF

1 September 2006 in 11:30

A.S. Ioselevich «Elektronnye i strukturnye svoistva sil’no neuporyadochennykh materialov» (dokt. diss.).

Zasedanie Dissertatsionnogo soveta ITF

30 June 2006 in 11:30

O.V. Dimitrova «Sverkhprovodimost’ i spinovyi transport v dvumernykh elektronnykh sistemakh so spin-orbital’nym vzaimodeistviem» (kand. diss.).

Gidrodinamicheskoe vzaimodeistvie malykh chastits

23 June 2006 in 11:30

P.E. Vorob’ev

Topologicheskie struny i funktsional Khitchina

16 June 2006 in 11:30

K.A. Saraikin

Prostranstvenno-vremennaya dispersiya provodimosti grafena

16 June 2006 in 11:30

L.A. Fal’kovskii, A. Varlamov

Ob universal’noi provodimosti grafena

9 June 2006 in 11:30

P.M. Ostrovskii

Novye rezul’taty, poluchennye v chislennykh eksperimentakh po poverkhnostnym volnam

2 June 2006 in 11:30

V.E. Zakharov, A.I. D’yachenko, A.O. Korotkevich, A.O. Prokof’ev, A.N. Pushkarev

Topologicheskie defekty v real’nom i impul’snom prostranstve

26 May 2006 in 11:30

G.E. Volovik

Nelineinaya $k_{\perp}$- faktorizatsiya i pravila unitarnosti dlya yadernykh vozbuzhdenii i topologicheskie secheniya v zhestkikh protsessakh na yadrakh

19 May 2006 in 11:30

N.N. Nikolaev, W. Schaefer, B.G. Zakharov

Potentsialy tyazhelykh kvarkov i AdS/QCD

5 May 2006 in 11:30

O.D. Andreev

Korrelyatsionnye funktsii minimal’noi liuvillevskoi gravitatsii

28 April 2006 in 11:30

A.V. Litvinov

«Dyshashchaya» ekstremal’naya volna, nablyudaemaya v chislennom eksperimente

21 April 2006 in 11:30

V.P. Ruban

Provedeno chislennoe modelirovanie slabo-trekhmernykh voln na vode s kvazi-sluchainymi nachal’nymi usloviyami. Pokazano, chto v rezul’tate razvitiya modulyatsionnoi neustoichivosti obrazuyutsya tak nazyvaemye volny-ubiitsy. V odnom iz chislennykh eksperimentov takaya ekstremal’naya volna prosushchestvovala v ostsilliruyushchem rezhime na protyazhenii mnogikh volnovykh periodov bez znachitel’nogo izmeneniya maksimal’noi amplitudy.

Odevayushchaya tsepochka dlya akusticheskikh spektral’nykh zadach

14 April 2006 in 11:30

V.E. Adler, A.B. Shabat

Termomekhanicheskie yavleniya pod deistviem ul’trakorotkogo lazernogo impul’sa

14 April 2006 in 11:30

S.I. Anisimov, N.A. Inogamov, Yu.V. Petrov, V.A. Khokhlov, V.V. Temnov, K. Sokolowski-Tinten, D. von der Linde, V.V. Zhakhovskii, K. Nishihara, A. Upadhyay, H.M. Urbassek, B. Rethfeld

Minishchel’ v kontaktakh sverkhprovodnik-ferromagnetik s neodnorodnoi namagnichennost’yu

7 April 2006 in 11:30

D.A. Ivanov, Ya.V. Fominov

Issledovana minishchel’ v neuporyadochennom ferromagnetike, kontaktiruyushchem so sverkhprovodnikom, v sluchae neodnorodnoi v prostranstve i nekollinearnoi namagnichennosti ferromagnetika. Sil’no neodnorodnaya namagnichennost’ effektivno usrednyaetsya, i minishchel’ sokhranyaetsya do obmennykh polei poryadka hc ~ (L/a) ETh, gde L ~V tolshchina ferromagnetika, a ~V masshtab izmeneniya namagnichennosti, ETh ~V energiya Taulesa. Dlya opisaniya sistemy ispol’zovana "tripletnaya" forma uravnenii Uzadelya, uchityvayushchaya kak singletnye, tak i tripletnye komponenty funktsii Grina. Vo mnogikh sluchayakh effekt neuporyadochennoi namagnichennosti mozhet byt’ effektivno vklyuchen v obychnoe uravnenie Uzadelya kak vklad, otvechayushchii paramagnitnym primesyam. Odnako v sluchae nizkorazmernoi magnitnoi neodnorodnosti (v kachestve primera my rassmatrivaem spiral’nuyu namagnichennost’) neobkhodimo reshat’ polnyi nabor "tripletnykh" uravneni Rezul’tat dlya kriticheskogo obmennogo polya tem ne menee soglasuetsya s privedennoi vyshe otsenkoi.

Defazirovka dzhozefsonovskikh kubitov vblizi optimal’nykh tochek

31 March 2006 in 11:30

S.V. Syzranov, Yu.G. Makhlin

Korrelyatsii raznykh volnovykh funktsii v kvaziodnomernom provode

24 March 2006 in 11:30

M.A. Skvortsov, P.M. Ostrovskii

Vychislena parnaya korrelyatsionnaya funktsiya lokal’nykh plotnostei sostoyanii na raznykh energiyakh v kvaziodnomernom neuporyadochennom provode v predele, kogda rasstoyanie mezhdu tochkami, v kotorykh schitaetsya korrelyator, mnogo men’she dliny lokalizatsii. V ramkakh formalizma supersimmetrichnoi sigma-modeli zadacha svoditsya k nakhozhdeniyu nulevoi mody gamil’toniana transfer-matritsy. Putem otobrazheniya na funktsiyu Grina v trekhmernom kulonovskom potentsiale polucheno tochnoe reshenie etoi zadachi. V zavisimosti ot rasstoyaniya, parnyi korrelyator opisyvaet kak ottalkivanie, tak i prityazhenie mezhdu urovnyami.

Ob integriruemykh modelyakh granichnogo vzaimodeistviya

17 March 2006 in 11:30

A.B. Zamolodchikov

O relaksatsii parametra poryadka v modeli BKSh

17 March 2006 in 11:30

S.V. Iordanskii, R.B. Saptsov

Bezmassovye vozbuzhdeniya pri θ=π v CP(N-1) modeli pri bol’shikh N

10 March 2006 in 11:30

A.M.M. Pruisken, I.S. Burmistrov, R. Shankar

Podrobno izuchen instantonnyi vakuum CP(N-1) modeli pri bol’shikh N. Nesmotrya na izvestnye v literature utverzhdeniya o tom, chto teoriya massivna, vpervye naidena kriticheskaya teoriya dlya fazovogo perekhoda pri θ=π. S pomoshch’yu otobrazheniya na nizko-temperaturnuyu fazu 1D modeli Izinga naideny: dvukhtochechnaya korrelyatsionnaya funktsiya, korrelyatsionnaya dlina s indeksom 1/2 i vyrazheniya dlya β-funktsii.

Universal’naya temperaturnaya zavisimost’ provodimosti sil’noneuporyadochennogo granulirovannogo metalla

3 March 2006 in 11:30

A.R. Akhmerov, A.S. Ioselevich

On magnetic susceptibility of a spin-S impurity in nearly ferromagnetic Fermi liquid

26 February 2006 in 11:30

I.S. Burmistrov

We present the renormalization group analysis for the problem of a spin-S impurity in nearly ferromagnetic Fermi liquid. We evaluate the renormalization group function that governs the temperature behavior of the invariant charge to the second order of both weak and strong coupling expansions. It allows us to determine behavior of the zero field magnetic susceptibility of impurity at low and high temperatures. We predict that derivative of the susceptibility with temperature should always have the maximum.

Periodic orbits of the ensemble of Sinai-Arnold cat maps and pseudorandom number generation

17 February 2006 in 11:30

L. Barash

We propose methods for constructing high-quality pseudorandom number generators (RNG) based on an ensemble of hyperbolic automorphisms of the unit two-dimensional torus (Sinai-Arnold map or cat map) while keeping a part of the information hidden. The single cat map provides the random properties expected from a good RNG and is hence an appropriate building block for an RNG, although unnecessary correlations are always present in practice. We show that introducing hidden variables and introducing rotation in the RNG output, accompanied with the proper initialization, dramatically suppress these correlations. We analyze the mechanisms of the single-cat-map correlations analytically and show how to diminish them. We generalize the Percival-Vivaldi theory in the case of the ensemble of maps, find the period of the proposed RNG analytically, and also analyze its properties. We present efficient practical realizations for the RNGs and check our predictions numerically. We also test our RNGs using the known stringent batteries of statistical tests and find that the statistical properties of our best generators are not worse than those of other best modern generators.

On local operators in Z(n) models

10 February 2006 in 11:30

Ya.P. Pugai

Parton energy loss in hot QCD medium and discovery of quark-gluon plasma in nuclear collisions at rhic

27 January 2006 in 11:30

B.G. Zakharov

Abstract The data obtained at the Relativistic Heavy Ion Collider (RHIC) in recent years provide evidences that a hot quark-gluon plasma with a temperature well above the deconfinement phase transition temperature is produced in Au+Au collisions. The major evidence in favor of the quark-gluon plasma production is the observation of strong suppression of the high-$p_{T}$ hadron spectra (so-called jet quenching phenomenon) in nucleus-nucleus collisions as compared to the proton-proton case which may be connected with parton energy loss due to the induced gluon emission from fast partons in the dense QCD medium produced in the initial stage of nucleus-nucleus collision. Comparison of the RHIC data on the jet quenching with theoretical prediction shows that the initial energy density of the QCD matter produced in Au+Au collisions at $\sqrt(s)=200$ GeV is about two order of magnitude larger than the nucleus density. We discuss the author's approach to the parton energy loss based on the light-cone path integral formalism and application to the jet quenching for RHIC conditions.

Critical Binder cumulant in two-dimensional anisotropic Ising models

13 January 2006 in 11:30

L.N. Shchur

The Inverse Scattering Problem for the Vector Fields and the Heavenly Equations

13 January 2006 in 11:30

S.V. Manakov

I. Zasedanie Dissertatsionnogo soveta: zashchita kandidatskoi dissertatsii - A.V. Lebedev II. Zasedanie Uchenogo soveta: 1. Itogi ukhodyashchego goda. Doklad direktora, diskussiya 2. Vydvizhenie A.A. Starobinskogo na medal’ im. Sakharova 3. Utverzhdenie otchetov nauchnykh shkol i utverzhdenie rukovoditelei nauchnykh shkol na 2006-2007 gg. 4. Obsuzhdenie prinyatiya A.V. Lebedeva na pozitsiyu 'post-dok' 5. Obsuzhdenie vydvizheniya na dolzhnosti: S.E. Korshunov, S.K. Nechaev - v vedushchie nauchnye sotrudniki P.M. Lushnikov - v nauchnye sotrudniki 6. Golosovanie po personaliyam III. Prazdnovanie Novogo Goda

30 December 2005 in 11:30

O dissertatsii A.S. Ioselevicha

23 December 2005 in 11:30

Insulating State of Granular Superconductors in a Strong Coupling Regime

9 December 2005 in 11:30

Ya.V. Fominov

Infrared properties of super-lattices

2 December 2005 in 11:30

L.A. Fal’kovsky

Surface anchoring and dynamics of jump-wise director reorientations in planar cholesteric layers

25 November 2005 in 11:30

A.V. Belyakov

Nature of phase transition(s) in striped phase of triangular lattice Ising antiferromagnet

25 November 2005 in 11:30

S.E. Korshunov

Scaling and front dynamics in Ising quantum chains

18 November 2005 in 11:30

Dragi Karevski (University Henri Poincare, Nancy, France)

We study the relaxation dynamics of a quantum Ising chain initially prepared in a product of canonical states corresponding each to an equilibrium state of part of the chain at a given temperature. We focus our attention on the transverse magnetization for which a general expression is given. Explicite results are given for the completely factorized initial state, corresponding to a situation where all the spins are hermalized independently, and for the two-temperatures initial state, where part of the chain called the system is thermalized at a temperature Ts and the remaining part is at a temperature Tb.

Once more about the Wilson fermion doubling problem

11 November 2005 in 11:30

S.N. Vergeles

Josephson Effect in a Coulomb-blockaded SINIS Junction

11 November 2005 in 11:30

P.M. Ostrovsky

On hierarchy and dressing method for Plebanskii equation

28 October 2005 in 11:30

L.V. Bogdanov

Sverkhprovodyashchii kontakt cherez dvumernyi elektronnyi gaz so spin-orbital’nym vzaimodeistviem Rashby

21 October 2005 in 11:30

O.V. Dimitrova, M.V. Feigelman

Kulonovskoe ushirenie ionnykh spektrov

14 October 2005 in 11:30

D.A. Shapiro (Institut avtomatiki i elektrometrii SO RAN)

V nachale 1980-kh byla ustanovlena prichina ushireniya provala Lemba v odnochastotnom ionnom lazere. Vozbuzhdennye iony aktivnoi sredy lazera, gazorazryadnoi plazmy, rasseivayutsya na malye ugly na ionakh v osnovnom sostoyanii, chto proyavlyaetsya kak diffuziya v prostranstve skorostei. Teoriya byla postroena v priblizhenii nezavisyashchei ot skorosti chastoty stolknovenii, v pervom poryadke teorii vozmushchenii po intensivnosti sveta i dlya begushchei volny. V doklade predstavleny nedavnie rezul’taty, demonstriruyushchie k kakim novym effektam privodit otkaz ot etikh predpolozhenii:
  1. Rasschitano suzhenie Dike ionnoi linii v plotnoi plazme s chandrasekarovkim tenzorom diffuzii po skorostyam. Predlozheno ispol’zovat’ effekt dlya izmereniya komponent tenzora.
  2. Pokazano, chto v sil’nom pole nasyshchenie ionnogo perekhoda stanovitsya odnorodnym, chto uvelichivaet effektivnost’ preobrazovaniya chastoty izlucheniya v kombinatsionnom ionnom lazere.
  3. Ustanovleno, chto osobenno chuvstvitel’ny k kulonovskoi defazirovke vysshie prostranstvennye garmoniki kogerentnosti, voznikayushchie pri vozbuzhdenii sistemy sil’noi stoyachei volnoi. Eksperiment po nablyudeniyu rasshchepleniya pika elektromagnitno-indutsirovannoi prozrachnosti ob’yasnen kolichestvenno.

Dual’nost’, bol’shoe lineinoe magnetosoprotivlenie i khollovskii perekhod v sil’no neodnorodnykh planarnykh sistemakh

7 October 2005 in 11:30

S.A. Bulgadaev

Sverkhprovodyashchii kontakt cherez dvumernyi elektronnyi gaz so spin-orbital’nym vzaimodeistviem Rashby

7 October 2005 in 11:30

O.V. Dimitrova, M.V. Feigelman

Non-Fermi liquid criticality in the quantum Hall regime

30 September 2005 in 11:30

I. Burmistrov

Generatsiya femtosekundnykh impul’sov (~30fs) predel’no bol’shikh energii (~mkDzh)

23 September 2005 in 11:30

V.L. Kalashnikov, E. Podivilov, A. Chernykh, S. Naumov, A. Fernandez, R. Gfaf, A. Apollonskii Institut fur Photonik, Austria. IAiE SO RAN, Rossiya. Max-Plank-Institut fur Quantenoptik, Germany

Tshchatel’noe eksperimental’noe issledovanie parametrov impul’sov generiruemykh Ti:Sa lazerom v dlinnykh rezonatorakh (15-75m) i detal’noe sravnenie poluchennykh rezul’tatov s modelyami opisyvayushchimi generatsiyu impul’sov v rezhime s normal’noi dispersiei pozvolilo opredelit’ osnovnye fizicheskie mekhanizmy ogranichivayushchie rost energii impul’sov. Na osnove poluchennykh predstavlenii udalos’ uvelichit’ energiyu generiruemykh impul’sov pochti na dva poryadka.

On the pairs of commuting quadratical on momenta Hamiltonians

9 September 2005 in 11:30

V.V. Sokolov, V.G Marikhin

Mesoscopic wave turbulence

2 September 2005 in 11:30

V.E. Zakharov, A.O. Korotkevich, A.N. Pushkarev, A.I. Dyachenko

We report results of sumulation of wave turbulence. Both inverse and direct cascades are observed. The definition of "mesoscopic turbulence" is given. This is a regime when number of modes in a system involved in turbulence is high enough to qualitatively simulate most of processes but significantly smaller then threshold which gives us quantitative agreement with statistical description, like kinetic equation. Such regime takes place in numerical simulation, essentially finite systems etc.

On the transition from regular to irregular motion as travel on a Riemann surface

2 September 2005 in 11:30

P.M. Santini

We introduce a simple Hamiltonian 3-body problem in the plane providing the prototype of a mechanism explaining the transition from regular to irregular motion as travel on Riemann surfaces.

Critical collapse of bacterial colonies

17 June 2005 in 11:30

P.M. Lushnikov

Use of small-scale quantum computers in cryptography with many-qubit entangled sates

10 June 2005 in 11:30

K.V. Bayandin

Correlation functions of descendants in the scaling Lee-Yang model

10 June 2005 in 11:30

O.V. Miroshnichenko

Quasiclassical approximation in hydrodynamics with free surface

3 June 2005 in 11:30

A.I. Dyachenko

N-orthogonal systems and spaces of flat connection

3 June 2005 in 11:30

V.E. Zakharov

Non-ideality corrections and phase transitions in Coulomb systems (on materials of D.Sc thesis)

27 May 2005 in 11:30

Igor Iosilevskiy (MIPT)

Molecular dynamics and kinetics of phase transformations at superheating and stretching of crystals and melts

27 May 2005 in 11:30

G.E. Norman, V.V. Stegailov (HED AIHT RAS)

Test of multiscaling in a diffusion-limited-aggregation model using an off-lattice killing-free algorithm (30 min)

20 May 2005 in 11:30

A. Menshutin

Universal relationships for amplitudes of secondary singularities in the critical points of two-dimensional systems

20 May 2005 in 11:30

A.B. Zamolodchikov

Bifurcations of solitons of internal waves

13 May 2005 in 11:30

D.S. Agafontsev

Quasi-planar steep water waves

6 May 2005 in 11:30

V.P. Ruban

A new description for highly nonlinear potential water waves is suggested, where weak 3D effects are included as small corrections to exact 2D equations written in conformal variables. Contrary to the traditional approach, a small parameter in this theory is not a surface slope, but it is the ratio of a typical wave length to a large transversal scale along the second horizontal coordinate. A first-order correction for the Hamiltonian functional is calculated, and the corresponding equations of motion are derived for steep water waves over an arbitrary non-uniform quasi-1D bottom profile.

Bose-condensation upon external cooling: numerical calculation of the optimal fluctuation’s parametrs in 3D and 2D

29 April 2005 in 11:30

R.B. Saptsov, S.V. Iordanskii

Influence of disorder on coherent transport in Josephson-junction rhombi chain

22 April 2005 in 11:30

I. Protopopov, M. Feigel’man

Spin-optics and diffuse emission for the purpose of spintronics

15 April 2005 in 11:30

A. Finkelstein

I-V characteristics of charge density waves

15 April 2005 in 11:30

S. Brazovsky

Wave function of the universe and topological strings

8 April 2005 in 11:30

K.A. Saraikin, S.G. Gukov, C. Vafa

Proximity and Josephson effects in the presence of Coulomb interaction and magnetic field

1 April 2005 in 11:30

Ya.V. Fominov, P.M. Ostrovsky, M.V. Feigelman

On three-point correlation function of two-dimensional Toda lattice

1 April 2005 in 11:30

A.V. Litvinov

On some multidimensional equations

18 March 2005 in 11:30

V.E. Adler

Superconductivity near localization edge

11 March 2005 in 11:30

T.I. Baturina (Institut fiziki poluprovodnikov, Novosibirsk)

On the puzzle of dephasing saturation at low temperatures

4 March 2005 in 11:30

V. Kozub (Ioffe PTI)

Is a kinetic equation applicable for description of an ensemble of weakly nonlinear waves in a despersive media?

4 March 2005 in 11:30

A.O. Korotkevich, A. Pushkarev, V.E. Zakharov and A.I. Dyachenko

Wave Function Collapse in a Mesoscopic Device

25 February 2005 in 11:30

G.B. Lesovik, A.V. Lebedev, and G. Blatter

We determine the non-local in time and space current-current cross correlator〈(x1, t1)(x2, t2)〉in a mesoscopic conductor with a scattering center at the origin. Its excess part appearing at finite voltage exhibits a unique dependence on the retarded variable t1t2 – (| x1| – | x2|)/vF, with vF the Fermi velocity. The non-monotonic dependence of the retardation on x1 and its absence at the symmetric position x1 = – x2 is a signature of the wave function collapse, which thus becomes amenable to observation in a mesoscopic solid state device.

Sverkhprovodimost’ vblizi poroga lokalizatsii

18 February 2005 in 11:30

M. Feigel’man, L. Ioffe, E. Yuzbashan

Predlozhena teoriya sverkhprovodyashchikh korrelyatsii dlya elektronov na lokalizovannykh sostoyaniyakh vblizi perekhoda Andersona. Rassmotreny kak dielektricheskoe, tak i sverkhprovodyashchee sostoyaniya. Pokazano, chto v dielektricheskom sostoyanii imeetsya zhestkaya shchel’, vyzvannaya kuperovskim vzaimodeistviem. Sverkhprovodyashchee sostoyanie kharakterizuetsya anomal’no bol’shim (po sravneniyu s obychnoi teoriei BKSh) otnosheniem odnochastichnoi shcheli v spektre k temperature perekhoda, a takzhe razvitiem "psevdoshcheli" v oblasti temperatur vyshe perekhoda.

Griffiths singularities in the random ferromagnetic Ising Model

11 February 2005 in 11:30

V.S. Dotsenko

The correlation functions of passive scalar in Bachelor's velocity field. The decaying case

4 February 2005 in 11:30

S.S. Vergeles

Variable range cotunneling: low temperature conductivity and magnetoconductance of a granular metal

28 January 2005 in 11:30

A.S. Ioselevich, M.V. Feigelman

Weakly-nonlocal structures, Whitham's method, and weakly-nonlocal structures of hydrodynamic type

21 January 2005 in 11:30

A.Ya. Maltsev

Decay of Richtmyer-Meshkov turbulence

14 January 2005 in 11:30

N.A. Inogamov, A.M. Oparin

Impulsive acceleration g(t) propto delta(t) imposed on randomly perturbed plane surface produces random velocity field near the surface. The surface separates two incompressible ideal (Re=infinity) fluids with different densities. Random velocity field moves contact surface and so mixes fluids. We consider how velocity field gradually decay in time.

Tunneling anomaly in quantum wires

30 December 2004 in 11:30

E.G. Mishchenko

The theory of non-critical strings. Four-point correlation function

24 December 2004 in 11:30

A.A. Belavin

Superconductivity in disordered thin films: giant mesoscopic fluctuations

17 December 2004 in 11:30

M.A. Skvortsov, M.V. Feigelman

Integrable lattices and their sub-lattices: from the discrete Moutard (discrete Cauchy-Riemann) 4-point equation to the self-adjoint 5-point integrable discretization of the two-dimensional Schrödinger operator - the finite gap solutions

10 December 2004 in 11:30

P.G. Grinevich

The scaling limit in SOS- and RSOS- models and formfactors of Sine-Gordon model and perturbed minimal models

3 December 2004 in 11:30

M.Yu. Lashkevich

Emission of matter from condensed targets after heating by ultrasoft laser pulse

3 December 2004 in 11:30

S.I. Anisimov, N.A. Inogamov, Yu.V. Petrov

Heating due to absorption of a part of energy of a laser pulse is the reason of complex motion of substance of a target including melting, spallation and spinodal decomposition. As a result inhomogeneous emission cloud and a crater are formed. We study such processes using hydrodynamical and molecular dynamics simulations.

On the dynamics of vortex lines

26 November 2004 in 11:30

V.E. Zakharov

Water waves over a time-dependent bottom: Exact description for 2D potential flows

19 November 2004 in 11:30

V.P. Ruban

Two-dimensional potential flows of an ideal fluid with a free surface are considered in situations when shape of the bottom depends on time due to external reasons. Exact nonlinear equations describing surface waves in terms of the so called conformal variables are derived for an arbitrary time-evolving bottom parameterized by an analytical function. An efficient numerical method for the obtained equations is suggested.

Fully frustrated XY-model on a dice lattice

12 November 2004 in 11:30

S.E. Korshunov

Note: The previous talk was about 1/3 of flux quantum per plaquette.

Magnetohydrodynamical models of plasma: Lagrangian properties and the problem of stability (on materials of D.Sc. thesis)

5 November 2004 in 11:30

V.I. Ilgisonis (Russian Research Centre Kurchatov Institute)

Instanton vacuum of generalized CPN-1 models

29 October 2004 in 11:30

I.S. Burmistrov

Surface anchoring and dynamics of pitch variation of chiral liquid crystalls

22 October 2004 in 11:30

V.A. Belyakov

Uniformly frustrated XY model without vortex pattern ordering

15 October 2004 in 11:30

S.E. Korshunov

Hadrons and strings

8 October 2004 in 11:30

O.D. Andreev

The dynamics of a concentration of particles and modification of the stream in the vortex flows (on materials of D.Sc. thesis)

1 October 2004 in 11:30

O.A. Druzhinin (Institute of Applied Physics RAS, Nizhnyi Novgorod)

Relativistic hodograph equation for a two-dimensional stationary isentropic hydrodynamical motion

1 October 2004 in 11:30

I.M. Khalatnikov

Collider Physics and Moduli of Holomorphic Curves

24 September 2004 in 11:30

S.G. Gukov

A neutron time focus lens

17 September 2004 in 11:30

R. Gaeler, P. Grigoriev, E.I. Kats

We examine in an analytic way imaging effects of temporal neutron lenses created by traveling non-homogeneous magnetic fields. It is shown how more neutrons of an available neutron flux can be compressed into a desired momentum, space, or time interval. To illustrate the issue we present a special solution (constant acceleration for each neutron during the full time of magnetic lens action) providing theoretically an arbitrary good time resolution. From the physical and technological aspect, no basic restrictions for a realization of such a system exist.
Applications may concern neutron instruments, where temporal imaging can enhance intensity and/or time resolution. New fields of application for high resolution neutron time of flight spectrometry can be opened.

Water waves over a strongly inhomogeneous bottom

10 September 2004 in 11:30

V.P. Ruban

Two-dimensional free-surface potential flows of an ideal fluid over a strongly inhomogeneous bottom are investigated with the help of conformal mappings. Weakly-nonlinear and exact nonlinear equations of motion are derived by the variational method for arbitrary seabed shape parameterized by an analytical function. As applications of this theory, band structure of linear waves over periodic bottoms is calculated, and evolution of a strong solitary wave running from a deep region to a shallow region is numerically simulated, as well as transformation of a solitary wave over an underwater barrier.

Two dimensional electron gas driven by strong alternating electric field

10 September 2004 in 11:30

A.B. Kashuba

Rayleigh-Taylor turbulence of immiscible fluids

3 September 2004 in 11:30

M.V. Chertkov, I.V. Kolokolov, V.V. Lebedev

The structure of superconducting state in fully frustrated wire network with dice lattice geometry

18 June 2004 in 11:30

S.E. Korshunov

Spin-Hall conductivity in Rashba 2DEG

18 June 2004 in 11:30

O.V. Dimitrova

Electron injection in a nanotube with leads: finite frequency noise-correlations and anomalous charges

18 June 2004 in 11:30

A.V. Lebedev, Adeline Crepieux, Thierry Martin

Lattice Quantum Chromodynamics and magnetic monopoles

11 June 2004 in 11:30

V.I. Zakharov (ITEP, Moscow and Max-Planck Institut, Munich)

Optimal canonical variables in the free surface dynamics of an ideal fluid

4 June 2004 in 11:30

V.E. Zakharov

Erenfest time in dynamical localization

4 June 2004 in 11:30

A.I. Larkin

General phenomenological theory of nonlinear hydrodynamic waves in regions with smooth loss of convexity of isentropes

28 May 2004 in 11:30

S.I. Anisimov, M.I. Tribelsky (MIREA)

Exact solution of the problem of probability density for a sum of random items

28 May 2004 in 11:30

M.I. Tribelsky (MIREA)

Tunable Fermi-Edge Resonance and Non-Commuting Scattering Matrices

21 May 2004 in 11:30

D. Abanin, L.S. Levitov

Resonant tunneling into an open quantum dot is proposed as a vehicle to achieve a tunable Fermi-edge resonance of a Mahan-Nozieres-deDominicis form with a variable exponent in the I-V characteristic. The effect of scattering in a mesoscopic quantum dot on the exponent is shown to depend on a single parameter, the reflection amplitude of an extended scattering matrix of the system. Changing the reflection coefficient by varying the dot coupling to the leads and scattering inside the dot allows to explore a wide range of exponents.

Density of states in d-wave superconductors of finite size

14 May 2004 in 11:30

Ya.V. Fominov

Density of states, thermal conductivity and plasmon attenuation of a two-dimensional electron gas

7 May 2004 in 11:30

E.G. Mishchenko

Is there an Ultimate Speed of Magnetic Switching?

30 April 2004 in 11:30

A.B. Kashuba

About the possible solution of cosmological constant problem in the frame of theory quantized by dynamic method

23 April 2004 in 11:30

S.N. Vergeles

Condensate formation and vortex creation in the cooling Bose-gas

23 April 2004 in 11:30

R.B. Saptsov

Theory of 4e versus 2e supercurrent in frustrated Josephson-junction rhombi chain

16 April 2004 in 11:30

I.V. Protopopov

Coulomb effects in a mesoscopic SINIS junction

9 April 2004 in 11:30

P.M. Ostrovsky

The Kowalewsky-Lyapunov test and integrable quadratic Hamiltonians on SO(4) and SO(3,1)

2 April 2004 in 11:30

V.V. Sokolov

Nonmonotonic dependence of transition temperature on external magnetic field in a superconductor with magnetic and spin-orbit impurities

26 March 2004 in 11:30

M.Yu. Kharitonov

Fluctuations and vortex pattern ordering in fully frustrated XY model with honeycomb lattice

19 March 2004 in 11:30

S.E. Korshunov

Elektron-dyrochnyi disbalans v mezoskopicheskikh strukturakh normal’nyi metall-sverkhprovodnik

19 March 2004 in 11:30

V.R. Kogan, A.F. Volkov, V.V. Pavlovskii

Dissipative quantum systems and conformal field theory

12 March 2004 in 11:30

V. Bazhanov

Phase transition to the state with zero conductivity

5 March 2004 in 11:30

M.V. Feigelman

Soft-mode turbulence as a new type of chaos in distributed systems

5 March 2004 in 11:30

M.I. Tribelsky

Topological percolation on a square lattice

27 February 2004 in 11:30

O.A. Vasilyev, S.K. Nechaev

We investigate the "topological percolation", i.e. the formation of an infinite cluster of mutually entangled threads in a (2+1)-dimensional system. We demonstrate that topological percolation belongs to the universality class of the standard 2D bond percolation. We compute the topological percolation threshold and demonstrate that the critical exponents of topological phase transition coincide with the ones of the standard 2D bond percolation. Our numerical check confirms well obtained analytical results.

Tumbling of polymers in shear flows with random strain

20 February 2004 in 11:30

K.S. Turitsyn, V.V. Lebedev, I.V. Kolokolov, M.V. Chertkov

Topologically protected ground states of spin and Josephson junction arrays and discrete Chern-Simons gauge theories

13 February 2004 in 11:30

L.B. Ioffe

Variational principle for frozen-in vortex structures interacting with sound waves

6 February 2004 in 11:30

V.P. Ruban

Charge transport through a SET with a mechanically oscillating island

30 January 2004 in 11:30

N.M. Chtchelkatchev, W. Belzig, and C. Bruder

We consider a single-electron transistor (SET) whose central island is a nanomechanical oscillator. The gate capacitance of the SET depends on the mechanical displacement, thus, the vibrations of the island vibrations may strongly influence the current-voltage characteristics, current noise, and higher cumulants of the current. Harmonic oscillations of the island and oscillations with random amplitude (e.g., due to the thermal activation) change the transport characteristics in a different way. The noise spectrum has a peak at the frequency of the island oscillations; when the island oscillates harmonically, the peak reduces to a δ-peak. We show that knowledge of the SET transport properties helps to determine in what way the island oscillates, to estimate the amplitude, and the frequency of the oscillations.

Freak waves and modulation instability

23 January 2004 in 11:30

A.I. Dyachenko

The anisotropic conductivity of two-dimensional electrons on half-filled high Landau levels

16 January 2004 in 11:30

I.S. Burmistrov

Decoherence in superconducting quantum bits by phonon radiation

9 January 2004 in 11:30

R.A. Usmanov, L.B. Ioffe, V.B. Geshkenbein, Ch. Helm, G. Blatter

Conformal Field Theory and Topological Strings

9 January 2004 in 11:30

K.A. Saraikin

Integrable Dynamics of Interface between Ideal Fluid and Light Viscous Fluid

9 January 2004 in 11:30

P.M. Lushnikov

Odnochastichnyi transport v neuporyadochennykh Andreevskikh provolokakh

26 December 2003 in 11:30

N.B. Kopnin

O kovariantnoi regulyarizatsii teorii Liuvillya i gravitatsii v vysshikh razmernostyakh

26 December 2003 in 11:30

D.I. Podol’skii

Impact of saturation on polarization effects in diffractive DIS

19 December 2003 in 11:30

I.P. Ivanov, N.N. Nikolaev, W. Schaefer

QCD evolution properties of high mass diffraction

19 December 2003 in 11:30

N.N. Nikolaev, W. Schaefer, B.G. Zakharov, V.R. Zoller

Spectra of Laplacians on regular lattices and Cayley graphs

5 December 2003 in 11:30

D.S. Lyubshin, S.V. Savchenko

Lagrangian approach in a problem of planar three-body motion

28 November 2003 in 11:30

A.B. Shabat, V.G. Marikhin

Form factors of exponential fields for two-parametrical family of integrable models of quantum field theory

21 November 2003 in 11:30

V. Fateev, M. Lashkevich

Phase stratification in quasi-two-dimensional metal close to a topological phase transition

14 November 2003 in 11:30

Ioselevich, F. Onufrieva, P. Pfeuty

Dephasing in disordered metals with superconductive grains

14 November 2003 in 11:30

M.A. Skvortsov, A.I. Larkin, M.V. Feigel’man

Spin dependent magnetoresistance in multiwall carbon nanotubes obtained by chemical vapour deposition

31 October 2003 in 11:30

Jean-Eric Wegrowe (Ecole Polytechnique, Paris)

Nonlinear sigma-model for long-correlated disorder

31 October 2003 in 11:30

V.R. Kogan, K.B. Efetov

Discrete gravity, the species doubling problem of Dirac fermions and quantum anomalies

24 October 2003 in 11:30

S.N. Vergeles

Forwarding stimulated Brillouin scattering instability of a spatially and temporally incoherent laser beam

17 October 2003 in 11:30

P.M. Lushnikov

Spatial and temporal incoherence of laser beam is used to suppress self-focusing in experiments on inertial confinement fusion. It is found a temporal instability due to forward stimulated Brillouin scattering, which couples the beam to transversely propagating low frequency ion acoustic waves. Instability can result in strong self-focusing even for very short beam correlation time. Outside the instability region, the wave kinetic equation is derived which describes stationary diffusion of laser beam.

Temperature pitch variations in planar cholesteristic layers: role of fluctuations and surface anchoring

10 October 2003 in 11:30

V.A. Belyakov

On (1+1)D anisotropic ballistic deposition with links to the Ulam problem and (2+1)D directed percolation

26 September 2003 in 11:30

S.K. Nechaev

Incompressible, inviscid, irrotational, and unsteady flows with circulation Γ around a distorted toroidal bubble are considered. A general variational principle that determines the evolution of the bubble shape is formulated. For a two-dimensional (2D) cavity with a constant area A, exact pseudo-differential equations of motion are derived, based on variables that determine a conformal mapping of the unit circle exterior into the region occupied by the fluid. A closed expression for the Hamiltonian of the 2D system in terms of canonical variables is obtained. Stability of a stationary drifting 2D hollow vortex is demonstrated, when the circulation is relatively large, gA3/22<< 1. For a circulation-dominated regime of three-dimensional flows a simplified Lagrangian is suggested, inasmuch as the bubble shape is well described by the center-line g{R}(ξ,t) and by an approximately circular cross-section with relatively small area, A(ξ,t)<< (oint |g{R}'|dξ)2 In particular, a finite-dimensional dynamical system is derived and approximately solved for a vertically moving axisymmetric vortex ring bubble with a compressed gas inside.

To one class of quadratic hamiltonians on SO(4)

26 September 2003 in 11:30

V.V. Sokolov

Toroidal bubbles with circulation in ideal hydrodynamics. A variational approach

19 September 2003 in 11:30

V.P. Ruban, J.J. Rasmussen

Incompressible, inviscid, irrotational, and unsteady flows with circulation Γ around a distorted toroidal bubble are considered. A general variational principle that determines the evolution of the bubble shape is formulated. For a two-dimensional (2D) cavity with a constant area A, exact pseudo-differential equations of motion are derived, based on variables that determine a conformal mapping of the unit circle exterior into the region occupied by the fluid. A closed expression for the Hamiltonian of the 2D system in terms of canonical variables is obtained. Stability of a stationary drifting 2D hollow vortex is demonstrated, when the circulation is relatively large, gA3/22 ≪ 1. For a circulation-dominated regime of three-dimensional flows a simplified Lagrangian is suggested, inasmuch as the bubble shape is well described by the center-line g{R}(ξ,t) and by an approximately circular cross-section with relatively small area, A(ξ,t) ≪ (∮ |g{R}'|dξ)2 In particular, a finite-dimensional dynamical system is derived and approximately solved for a vertically moving axisymmetric vortex ring bubble with a compressed gas inside.

Coulomb Blockade of Proximity Effect at Large Conductance

19 September 2003 in 11:30

P.M. Ostrovski

Dirichlet problem for the non-linear Schroedinger equation

12 September 2003 in 11:30

P.G. Grinevich

Entanglement in one-dimensional and two-dimensional quantum systems

5 September 2003 in 11:30

A.Yu. Kitaev

Boundary conditions and 3D Larkin-Ovchinnikov-Fulde-Ferrel states in ferromagnet/superconductor heterostructures

20 June 2003 in 11:30

M.G. Khusainov (Kazan’ State Technical University)

Correlation functions in the scaling M(2,7) model

20 June 2003 in 11:30

A. Litvinov

Exact results for conductivity of 2D isotropic heterophase systems

6 June 2003 in 11:30

S.A. Bulgadaev

6 June 2003 in 11:30

K.A. Saraikin

Classification of the Egorov hydrodynamic chains and corresponding (2 + 1) integrable dispersionless systems

30 May 2003 in 11:30

M.V. Pavlov

Weak turbulence of gravity waves

25 April 2003 in 11:30

A.O. Korotkevich, A.I. Dyachenko, V.E. Zakharov

Decoherence due to nodal quasiparticles in D-wave qubits

25 April 2003 in 11:30

Ya.V. Fominov, A.A. Golubov, M.Yu. Kupriyanov

We study the Josephson junction between two d-wave superconductors, which is discussed as an implementation of a qubit. We propose an approach that allows to calculate the decoherence time due to an intrinsic dissipative process: quantum tunneling between the two minima of the double-well potential excites nodal quasiparticles which lead to incoherent damping of quantum oscillations. The decoherence is weakest in the mirror junction, where the contribution of nodal quasiparticles corresponds to the superohmic dissipation and becomes small at small tunnel splitting of the energy level in the double-well potential. For available experimental data, we estimate the quality factor.

Triplet proximity effect in FSF trilayers

18 April 2003 in 11:30

Ya.V. Fominov, A.A. Golubov, M.Yu. Kupriyanov

We study the critical temperature Tc of FSF trilayers (F is a ferromagnet, S is a singlet superconductor), where the triplet superconducting component is generated at noncollinear magnetizations of the F layers. An exact numerical method is employed to calculate Tc as a function of the trilayer parameters, in particular, mutual orientation of magnetizations. Analytically, we consider limiting cases. Our results determine conditions which are necessary for existence of recently investigated odd triplet superconductivity in SF multilayers.

Phase diagram of a surface superconductor in parallel magnetic field

18 April 2003 in 11:30

O.V. Dimitrova

Detailed theory of phase diagram of clean 2D surface superconductor in a parallel magnetic field is presented. Regular spin-orbital interaction of the Rashba type leads to the inhomogeneous superconductive state of the Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) type. We consider the case of relatively strong Rashba interaction and show that at low temperatures the LOFF-type state is separated from the usual homogeneous state by the first-order phase transition line. At higher temperatures new "helical" state intervenes between uniform BCS state and LOFF-like state. At the second-order transition line between BCS state and helical state one component of the superfluid density vanishes.

On universal rank distribution of WWW sites by popularity

4 April 2003 in 11:30

A.B. Teslyuk, S.A. Krashakov, L.N. Shchur

Fractional Quantum Hall effect, Jain’s rule and topological textures

28 March 2003 in 11:30

S.V. Iordanskii

On the Aizenman exponent in critical percolation

21 March 2003 in 11:30

L.N. Shchur, T. Rostunov

The probabilities of clusters spanning a hypercube of dimensions two to seven along one axis of a percolation system under criticality were investigated numerically. We used a modified Hoshen--Kopelman algorithm combined with Grassberger's "go with the winner" strategy for the site percolation. We carried out a finite-size analysis of the data and found that the probabilities confirm Aizenman's proposal of the multiplicity exponent for dimensions three to five. A crossover to the mean-field behavior around the upper critical dimension is also discussed.

Formation of singularities on the free surface of liquids in an electric field

14 March 2003 in 11:30

N.M. Zubarev

A generalisation of the Heckmann-Schucking cosmological solution

7 March 2003 in 11:30

I.M. Khalatnikov

Is dark energy decaying?

7 March 2003 in 11:30

U. Alam, V. Sahni, A.A. Starobinsky

Tetrahedral superconducting qubit

28 February 2003 in 11:30

M.V. Feigelman, L. Ioffe, G. Blatter

Topological phase transition and critical state of a porous metal

21 February 2003 in 11:30

A.S. Ioselevich

Mean-field phase diagram of 2D electrons with disorder in a weak magnetic field

21 February 2003 in 11:30

I. Burmistrov

Numerical simulation of decaying capillary wave of large amplitude

21 February 2003 in 11:30

A. Dyachenko, A. Korotkevich

Multiparametric family of collapse solutions of critical nonlinear Schroedinger equation

7 February 2003 in 11:30

Yu.N. Ovchinnikov

Inelastic light scattering from polar insulators

31 January 2003 in 11:30

L.A. Falkovsky

Orbital quantization in the high magnetic field state of a charge density wave system

31 January 2003 in 11:30

P.D. Grigoriev

Applicability of the hodograph method in the problem of long-scale nonlinear dynamics of a thin vortex filament near a flat boundary

24 January 2003 in 11:30

V.P. Ruban

Quasiperiodic functions and 2D electron gas

17 January 2003 in 11:30

A.Ya. Maltsev

On the integration of some hierarchies of (2 + n) dimensional partial differential equations

10 January 2003 in 11:30

A. Zenchuk

Perturbative Analysis of Multi-Cut Matrix Models

10 January 2003 in 11:30

S. Gukov

Longitudinal conductivity in layered metals under strong magnetic field

5 January 2003 in 11:30

V.P. Mineev

O vozmozhnosti realizatsii ideal'nogo kvantovogo bita v sisteme, sostavlennoi iz Dzhozefsonovskikh kontaktov

5 January 2003 in 11:30

R. Usmanov

Factorization and transformations of differential equations. DSc degree thesis - 20 min

27 December 2002 in 11:30

L.M. Berkovich

Long Tail of Outage Probability

27 December 2002 in 11:30

V.V. Lebedev

Bihamiltonian elliptic structures

27 December 2002 in 11:30

A.I. Odesskii

Scientific council

27 December 2002 in 11:30

Two-phase turbulence in sloping pipes

20 December 2002 in 11:30

A.Yu. Dem’yanov, N.A. Inogamov, A.M. Oparin

Free field construction of D-branes in N=2 superconformal minimal models

20 December 2002 in 11:30

S.E. Parkhomenko

Charget complexes at the surface of liquid helium

15 December 2002 in 11:30

A.M. Dyugaev, P.D. Grigoriev, P. Wyder

Duality and effective conductivity of two-dimensional two-phase systems

15 December 2002 in 11:30

S.A. Bulgadaev

Composite models of 2D random two-phase systems

15 December 2002 in 11:30

S.A. Bulgadaev

Dynamic localization in quantum dots

6 December 2002 in 11:30

M.A. Skvortsov

On Solutions to Commutativity Equations

6 December 2002 in 11:30

I.V. Polyubin

Disappearance of jet-jet correlations in deep inelastic production off nuclear targets

29 November 2002 in 11:30

N.N. Nikolaev, W. Schaefer, V.R. Zoller, B.G. Zakharov

Quantum correction to the Kubo formula in closed mesoscopic systems

22 November 2002 in 11:30

M.A. Skvortsov

New problems in perturbation theory and their solutions for generic case

22 November 2002 in 11:30

S.V. Savchenko

All the people are used to thinking that only new eigenvalues which appear in a small neighborhood of a fixed eigenvalue λ of the original operator A are considered in the classical perturbation theory. However, if the number of linear independent eigenvectors for λ is greater than the rank r of a perturbation B, then λ must also be in the spectrum of the new operator C = A + B. What can one say about the change of the spectral properties of λ when the matrix A is replaced by C? In our paper we show that a generic perturbation of rank r changes the Jordan form of λ in the following way: r largest Jordan blocks disappear and all the others remain the same. For the new matrix, the part of a Jordan basis corresponding to the eigenvalue is constructed. By means of the resolvent technique and the Binet-Cauchy formula we obtain the equation of the critical surface in the space of matrix entries of a perturbation out which the typical change of the spectral properties takes place. For the new eigenvalues we develop the first order perturbation theory.

On the Cauchy problem for integrable discrete equation on quad-graph

15 November 2002 in 11:30

V.E. Adler, A.P. Veselov

Dynamics of energy levels and Ruijsenaars-Shneider system

15 November 2002 in 11:30

V.G. Marikhin

Symmetric approach for nonevolutionary equations

10 November 2002 in 11:30

V.V. Sokolov

New classes of exact solutions for chiral SU(2) field (D = 3) and n-field (D = 3 + 1) and their geometric interpretation

1 November 2002 in 11:30

A.B. Borisov

Electron-phonon renormalization

25 October 2002 in 11:30

L.A. Falkovski

Dynamics of the Bose-condensate

18 October 2002 in 11:30

V.E. Zakharov

Topological order in the insulating Josephson junction array (part II)

18 October 2002 in 11:30

B. Doucot, M. Feigelman, L. Ioffe

Topological order in the insulating Josephson junction array

11 October 2002 in 11:30

B. Doucot, M. Feigelman, L. Ioffe

Theory of pseudogaps in change density and 1D semiconductors

4 October 2002 in 11:30

S.I. Matveenko

Prerain droplets collisions in turbulent flow

27 September 2002 in 11:30

G. Fal’kovich, A. Fukson, M. Stepanov

Local approximation for contour dynamics in effectively two-dimensional ideal electron-magnetohydrodynamic flows

27 September 2002 in 11:30

V.P. Ruban and S.L. Senchenko

The evolution of piecewise constant distributions of a conserved quantity related to the frozen-in canonical vorticity in effectively two-dimensional incompressible ideal EMHD flows is analytically investigated by the Hamiltonian method. The study includes the case of axisymmetric flows with zero azimuthal velocity component and also the case of flows with the helical symmetry of vortex lines. For sufficiently large size of such a patch of the conserved quantity, a local approximation in the dynamics of the patch boundary is suggested, based on the possibility to represent the total energy as the sum of area and boundary terms. Only the boundary energy produces deformation of the shape with time. Stationary moving configurations are described.

2D multicomponent dense electron gas as a model of Si MOSFET

18 September 2002 in 11:30

S.V. Iordanski, A.B. Kashuba

Weak Coulomb blocade on superconducting island

6 September 2002 in 11:30

M.V. Feigelman, A. Kamenev, M.A. Skvortsov, A.I. Larkin

Single carbon nanotube-superconductor entangler: noise correlations and EPR states

6 September 2002 in 11:30

N.M. Chtchelkatchev

On the construction of particular solution to nonlinear equations of mathematical physics

21 June 2002 in 11:30

A.I. Zenchuk

Centre of Quantum Group for 8-Vertex Model

14 June 2002 in 11:30

A.A. Belavin

Jahn-Teller effect in inverse Si-layers

14 June 2002 in 11:30

S.E. Brener

Schmidt theorem analogue for multipartite states

7 June 2002 in 11:30

S.B. Bravyi

Disclination motion in liquid crystalline films

7 June 2002 in 11:30

E.I. Kats, V.V. Lebedev, S.V. Malinin

We present theoretical study of a single disclination motion in a thin free standing liquid crystalline film. Back-flow effects and own dynamics of the orientational degree of freedom (bond or director angle) are included. We find the the orientation field and the hydrodynamic velocity distribution around the moving disclination, what allows us to relate the disclination velocity to the angle gradient far from the disclination. Different cases are examined depending on the ratio of the rotational and shear viscosity coefficients.

Interlayer magnetotransport in quasi-2D metals

31 May 2002 in 11:30

P.D. Grigoriev

The Shubnikov-de Haas effect in quasi-two-dimensional normal metals is studied. The interlayer conductivity is calculated using the Kubo formula. The electron scattering on short-range is considered in the self-consistent Born approximation. The result obtained differs from that derived from the Boltzmann transport equation. This difference is shown to be a general feature of conductivity in magnetic field. A detailed description of the two new qualitative effects — the field-dependent phase shift of beats and of the slow oscillations of conductivity is provided. The results obtained are applicable to strongly anisotropic organic metals and to other quasi-two-dimensional compounds.

Nonsinusoidal current-phase relation in SFS Josephson junctions

31 May 2002 in 11:30

Ya.V. Fominov, A.A. Golubov, M.Yu. Kupriyanov

Various types of the current-phase relation I(φ) in superconductor-ferromagnet-superconductor (SFS) point contacts and planar double-barrier junctions are studied in the limit of thin diffusive ferromagnetic interlayers. The physical mechanisms leading to highly nontrivial I(φ) dependence are identified by studying the spectral supercurrent density. These mechanisms are also responsible for the 0-π transition in SFS Josephson junctions.

Dynamics of two well system interacting with random classical field

24 May 2002 in 11:30

G.B. Lesovik, A.V. Lebedev, A.O. Imambekov

Integrable system of particles on algebraic curves

24 May 2002 in 11:30

A.A. Akhmetshin

Analog of Kelvin-Helmholtz instability on superfluid liquid free surface

17 May 2002 in 11:30

S.E. Korshunov

Mean-field model of a glass

17 May 2002 in 11:30

V.S. Dotsenko

Universality of the crossing probability for the Potts model for q = 1, 2, 3, 4

27 April 2002 in 11:30

O.A. Vasiliev

The universality of the crossing probability πhs of a system to percolate only in the horizontal direction, was investigated numerically by using a cluster Monte-Carlo algorithm for the q-state Potts model for q = 2, 3, 4 and for the percolation q = 1. We check the percolation through Fortuin-Kasteleyn clusters near the critical point on the square lattice by using representation of the Potts model as the correlated site-bond percolation model. It was shown that probability of a system to percolate only in the horizontal direction πhs has universal form πhs = A(q) Q(z) for q =1, 2, 3, 4 as a function of the scaling variable z = [b(q)L1/ν(q)(ppc(q,L)) ]ζ(q). Here, p = 1 − exp(−β) is the probability of a bond to be closed, A(q) is the nonuniversal crossing amplitude, b(q) is the nonuniversal metric factor, ζ(q) is the nonuniversal scaling index, ν(q) is the correlation length index. The universal function Q(x) ≃ exp(-z). Nonuniversal scaling factors was found numerically.

Perturbative symmetry approach

27 April 2002 in 11:30

V.S. Novikov, A.V. Mikhailov

Structure and stability of high pressure phases in binary sp metal alloys

26 April 2002 in 11:30

V.F. Degtyareva

Decay instability of cappilar wave

26 April 2002 in 11:30

A.O. Korotkevich, A.I. Dyachenko

Gravity or convective turbulent mixing

19 April 2002 in 11:30

N.A. Inogamov, A.M. Oparin

Rayleigh-Taylor instability (RTI) is important for inertial confinement fusion (ICF), astrophysics and for atmospheric and oceanological applications. Mechanics of RTI is similar to the mechanics of convection. Therefore it is meaningful to consider both phenomena from common positions. The first part of work is devoted to this. The role of geometrical restrictions as lateral walls or horizontal plates is analyzed in this part. The structure of near-wall layers near such plates is studied. In the second part the internal structure of zone of RT turbulence (TMZ - turbulent mixing zone) is investigated numerically in case of mixing near a separation surface of two liquids of different density.
(i) Existence of fast descending and ascending jets is revealed. Speed of movement of substance in them exceed speed of TMZ front. Deceleration of the fast moving jets occurs in a small vicinity of front. Such sharp deceleration results in occurrence of spots in which absolute values of deceleration are high. They exceed archimedean value gA = (1-μ) g and are much larger than mean acceleration ddot h+ of front, where μ=ρl/ρh <1 - is the ratio of densities. Spot is formed in a place of crossing of front and a jet. Other interesting detail of a mixing zone is occurrence of small areas of sharp pressure drop. In them there is a strong acceleration of a light liquid.
(ii) The questions on characteristic horizontal scale of structures from bubbles and jets in a TMZ and on a spectrum of long-wave fluctuations are investigated.

Excitations in quantum Hall ferromagnet with strong Coulomb interaction

19 April 2002 in 11:30

S.V. Iordansky, A.B. Kashuba

Entropy of a multi-particle pure quantum state

12 April 2002 in 11:30

S. Bravyi

M-theory and new singular G2-holonomy manifolds

12 April 2002 in 11:30

S. Gukov, K. Saraikin, A. Volovich

An example of amorphous lattice in which fermion doubling is absent

5 April 2002 in 11:30

S.N. Vergeles

Autowaves in the near threshold medium

5 April 2002 in 11:30

E.N. Rumanov, A.Yu. Dovzhenko

Quasiclassical dbar-dressing method and generating equations for dispersionless hierarchies

29 March 2002 in 11:30

L.V. Bogdanov

An example of amorphous lattice in which fermion doubling is absent

29 March 2002 in 11:30

S.N. Vergeles

Neravnovesnye effekty pri tunnelirovanii cherez vzaimodeistvuyushchie andersonovskie primesi

22 March 2002 in 11:30

N. Maslova (MGU-FIAN)

Доклад по докторской диссертации.

Ob universal’nykh otnosheniyakh kriticheskikh amplitud dvumernykh modelei Pottsa

22 March 2002 in 11:30

L.N. Shchur

Sklyanin brackets and deformations of integrable dynamical systems

15 March 2002 in 11:30

V. Sokolov

To the equation of state for lambda-term

15 March 2002 in 11:30

D. Podolsky

Critical current in SFIFS junctions

1 March 2002 in 11:30

Ya.V. Fominov

Electron transport in S/F-N-S/F junctions

1 March 2002 in 11:30

N.M. Chtchelkatchev

Saturation of nuclear partons

1 March 2002 in 11:30

N.N. Nikolaev

Effect of electron-phonon interaction on phonons renormalization

22 February 2002 in 11:30

L.A. Falkovsky

The angular dependence of Hc2 in layered superconductors

15 February 2002 in 11:30

Yu.N. Ovchinnikov, S.I. Vedeneev

Temperature and field hysteresis in a change of step of chiral liquid crystal in the thin layers

8 February 2002 in 11:30

V.A. Belyakov

Two-dimensional electron liquid with disorder in a weak magnetic field

1 February 2002 in 11:30

I.S. Burmistrov

Multi-phase solutions (nonintegrable case)

1 February 2002 in 11:30

A.B. Shabat

Generalized Heisenberg model

25 January 2002 in 11:30

S.Yu. Gubanov

An example of amorphous lattice in which fermion doubling is absent

25 January 2002 in 11:30

S.N. Vergeles

Random diffusion of optical pulse width in a disordered anisotropic optical media

18 January 2002 in 11:30

P.M. Lushnikov

A propagation of optical pulse in a one-dimensional optical media (optical fiber) with anisotropy disorder and random dispersion is described by a vector nonlinear Schrödinger equation with random coefficients. An averaged pulse width is shown to diffuse with propagation distance along optical fiber.

Local action of the symmetric group and twisted YB relation

11 January 2002 in 11:30

A.V. Odesskii

Real algebra-geometrical solutions to the Sine-Gordon equation: formula for topological charge

4 January 2002 in 11:30

P.G. Grinevich, S.P. Novikov

Magnetoresistance oscillations in quasi-2D metals

4 January 2002 in 11:30

P.D. Grigoriev

Spectral flow in superconducting point contacts

28 December 2001 in 11:30

N.B. Kopnin

Black holes in D = 2

28 December 2001 in 11:30

S.G. Gykov

Topological correlations in trivial knots: new arguments argues for the crumple polymer globule

21 December 2001 in 11:30

O.A. Vasiliev

Chaplygin gas state equation in cosmology and brane physics

21 December 2001 in 11:30

A.Yu. Kamenshchik

Reservoir as a source for probability in quantum mechanics

14 December 2001 in 11:30

G.B. Lesovik

We propose a concept of theory of measurement in quantum mechanics. The result of the measurement in our concept is determined by the state of all involoved reservoirs (including the detector). Thus the reservoirs variables serve as a non-local "hidden" variables. We discuss the problems of derivation of the "psi squared" (due to Born) rule from the first principles. We discuss how one can technically to demonstrate the wave packet reduction, key question in the problem of measurement. We propose a way to resolve the "Schrödinger cat" paradox. Finally we discuss a connection of flicker and shot noise with the interpretation of quantum mechanics we proposed.

Ion currents in the flat membrane

7 December 2001 in 11:30

V.G. Kamenski

Upper critical field in a trigonal unconventional superconductor (UPt3)

7 December 2001 in 11:30

P.L. Krotkov, V.P. Mineev

A theory of the upper critical field in a trigonal superconductor with a two-component order-parameter is developed. We demonstrate the existence of sixfold modulations of the upper critical field in the basal plane. The form of the angular dependence of Hc2 in the plane of the main symmetry axis is studied in the whole range of phenomenological rigidity coefficients. A qualitative dependence Hc2 in the heavy fermion superconductor UPt3 that has been recently found to possess trigonal crystalline structure.

Spin susceptibility of the superfluid 3He-B in aerogel

30 November 2001 in 11:30

V.P. Mineev and P.L. Krotkov

The temperature dependence of paramagnetic susceptibility of the superfluid He-B in aerogel is found. Calculations have been performed for an arbitrary phase shift of s-wave scattering in the framework of BCS weak coupling theory and the simplest model of aerogel as an aggregate of homogeneously distributed ordinary impurities. Both limiting cases of the Born and unitary scattering can be easily obtained from the general result. The existence of gapless superfluidity starting at the critical impurity concentration depending on the value of the scattering phase has been demonstrated. While larger than in the bulk liquid the calculated susceptibility of the B-phase in aerogel proves to be conspicuously smaller than that determined experimentally in the high pressure region.

Atoms in superintense laser fields and attosecond pulse generation

23 November 2001 in 11:30

S. Gordienko, T. Meyer-ter-Vehr (MPQ, Garching)

Hall effect in three-dimensional layered structures in strong magnetic fields

16 November 2001 in 11:30

S.E. Brener

Collapse in hydrodynamics and Kolmogorov spectra

16 November 2001 in 11:30

E.A. Kuznetsov

On the classification of discrete KdV-type systems

9 November 2001 in 11:30

V.E. Adler

Class of exact multisolitons, topological charge and color-conversion phenomenon in media with cubic nonlinearity

26 October 2001 in 11:30

A. Agalarov

On the form-factors in perturbed minimal CFT

19 October 2001 in 11:30

Ya.P. Pugai

Schwinger type processes via branes and their gravity duals

12 October 2001 in 11:30

A. Gorsky, K. Saraikin and K. Selivanov

We consider Schwinger type processes involving the creation of the charge and monopole pairs in the external fields and propose interpretation of this processes via corresponding brane configurations in Type IIB string theory. We propose simple description of some interesting processes like monopole/dyon transitions in the electric field and W-boson/monopole transition in the magnetic field using the brane language. We study nonperturbative pair production in the strong coupling regime using the AdS/CFT correspondence. The treatment of the similar processes in the noncommutative theories where noncommutativity is traded for the background fields is presented and the possible role of the critical magnetic field which is S-dual to the critical electric field is discussed.

π-0 transition in superconductor-ferromagnet-superconductor junctions

12 October 2001 in 11:30

N. Chtchelkatchev

Magnetic Field-Induced-Spin (Charge) Density Wave Phases

5 October 2001 in 11:30

A.G. Lebed’

New algebraic structures related with Baxter Q-operator

28 September 2001 in 11:30

A. Belavin, A. Odesskii, R. Usmanov

Mi rassmatrivaem neprivodimie ciklicheskie predstavleniya algebri matric monodromii, sootvetstvuyushie R-matrice shestivershinnoi modeli. V kornyah iz edinici Q-operator Baxtera mojet bit predstavlen kak sled proizvedeniya L-operatorov, otvechayushih odnomu iz takih predstavlenii. Dlya nego spravedlivo TQ-uravnenie.

Quantum dimers from the Heisenberg model

28 September 2001 in 11:30

A.S. Ioselevich

Polarization of vector mesons from inclusive hard processes

21 September 2001 in 11:30

N.N. Nikolaev