N | Speeker | Institution | Arrival | Departure | Abstract Title | Abstracts | File Name of Talk | Speak Date/Time | |
---|---|---|---|---|---|---|---|---|---|

1 | Ferdinand Evers | Institute of Theoretical Physics, University of Regensburg | 2023-06-23 | 2023-06-27 | Many-Body (De-)localization - A perspective on the status of affairs | The interplay between Anderson localization and true many-body interactions is one of the most intriguing research areas in condensed matter physics. In this context, the concept of many-body localization (MBL) was introduced more than a decade ago. It implies the survival of Anderson localization under sufficiently strong disorder even at finite temperatures and in the presence of interaction-induced dephasing effects. An initial flurry of activity, both experimental and numerical, provided evidence that was interpreted as supporting the existence of the MBL in generic disordered single-channel wires. However, after a controversial discussion, a consensus was reached that the original conclusions, which ignored finite-size and finite-time effects, were premature. The talk gives a brief overview of the state of affairs and then highlights a fresh concept that has recently been proposed, the "internal clock of many-body (de)localization". | ferdinand.evers@ur.de | no | |

2 | Anastasia Lyublinskaya | L.D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-30 | Diffusive modes in a two-dimensional fermionic gas with number conserving dissipative dynamics | Recently, there has been increasing interest in studying the behavior of many-particle systems in nonequilibrium states. The development of experimental platforms simulating such systems (for example, ultracold atoms and exciton-polariton systems) entails the need to construct an appropriate theory. In this paper, we consider a two-band dissipative fermionic system proposed in [1]. It is a two-dimensional fermionic gas with a quadratic spectrum corresponding to a topological insulator and subject to dissipation in the framework of the Gorini-Kosakovski- Sudarshan-Lindblad (GKSL) equation. The introduced Lindblad operators preserve the number of particles and are aimed at transferring the population from the upper zone of the Hamiltonian spectrum to the lower one. The dissipation is conceived in such a way as to stabilize the ground state of the Hamiltonian, the dark state, corresponding to the complete filling of the lower zone due to the depletion of the upper one. In the paper [2], which has not yet been published, it is shown that in the model under study there is an interval of spatial and temporal scales with diffusive dynamics of quasiparticles. We emphasize that diffusion arises due to operators of “quantum jumps” in the absence of any disorder. The aim of our work is a more complete description of the diffusive regime. Using the approach of the Keldysh functional integral for the GKSL equation [3], we obtained an expression for the diffuson describing the dynamics of quasiparticles near the bottom of the upper band. The derived diffusion coefficient is inversely proportional to the dissipation force and coincides with the result of [2]. The self-energy of diffusons was also calculated, which is related to the diagrams beyond the ladder approximation. The work is supported by the RSF project 22-22-00641. References [1] F. Tonielli, J. C. Budich, A. Altland, S. Diehl, Phys. Rev. Lett. 124, 240404 (2020). [2] P. A. Nosov, D. S. Shapiro, M. Goldstein, I. S. Burmistrov, arXiv:2301.05258 (2023). [3] L. M. Sieberer, M. Buchhold, S. Diehl, Rep. Prog. Phys. 79, 096001 (2016). | lyublinskaya.aa@phystech.edu | 1680180843abstract_Landau_Week_2023.pdf | |

3 | Ilia Kochergin | Princeton University | 21/06/2023 | 30/06/2023 | Isometry invariance of exact correlation functions in various charts of Minkowski and de Sitter spaces | ikochergin@princeton.edu | |||

4 | Aleksandr Artemev | Landau Institute for Theoretical Physics | 21/06/2023 | 30/06/2023 | New results on correlation numbers in minimal Liouville gravity | artemev.aa@phystech.edu | |||

5 | Sergey Belan | L. D. Landau Institute for Theoretical Physics | 2023-06-22 | 2023-06-25 | Universal performance bounds of restart | As has long been known to computer scientists, the performance of probabilistic algorithms characterized by relatively large runtime fluctuations can be improved by applying a restart, i.e., episodic interruption of a randomized computational procedure followed by initialization of its new statistically independent realization. A similar effect of restart-induced process acceleration could potentially be possible in the context of enzymatic reactions, where dissociation of the enzyme-substrate intermediate corresponds to restarting the catalytic step of the reaction. To date, a significant number of analytical results have been obtained in physics and computer science regarding the effect of restart on the completion time statistics in various model problems, however, the fundamental limits of restart efficiency remain unknown. We derived a range of universal statistical inequalities that offer constraints on the effect that restart could impose on the completion time of a generic stochastic process. The corresponding bounds are expressed via simple statistical metrics of the original process such as harmonic mean, median value and mode, and, thus, are remarkably practical. | sergb27@yandex.ru | no | |

6 | Nikolay Nikolayev | L. D. Landau Institute for Theoretical Physics | 2023-06-22 | 2023-06-25 | Axions: from the CP puzzle in QCD to spins in storage rings as ab axion antenna | nikolaev@itp.ac.ru | no | ||

7 | Alexander Kamenshchik | Some new solutions of the Einstein equations in cosmology and black hole physics. | We present a new exact solution of Einstein equations for the Bianchi-I universe filled with the magnetic field and analyse its connection with the known solutions for Bianchi-I cosmologies. We also present some non-singular solutions for cosmological models and black holes and discuss possible relations between the regularity and non-analyticity. | Alexander.Kamenshchik@bo.infn.it | no | ||||

8 | Moshe Goldstein | Information theoretical bounds on quantum critical exponents | Information theory, rooted in computer science, and many-body physics, have traditionally been studied as (almost) independent fields. Only recently has this paradigm started to shift, with many-body physics being studied and characterized using tools developed in information theory. In our work, we introduce a new perspective on this connection, and study phase transitions in models with randomness, such as localization in disordered systems, or random quantum circuits with measurements. Utilizing information-based arguments regarding probability distribution differentiation, we bound critical exponents in such phase transitions (specifically, those controlling the correlation or localization lengths). We benchmark our method and rederive the well known Harris criterion, bounding critical exponents in the Anderson localization transition for noninteracting particles, as well as classical disordered spin systems. We then move on to apply our method to many-body localization. While in real space our critical exponent bound agrees with recent consensus, we find that, somewhat surprisingly, numerical results on Fock-space localization for limited-sized systems do not obey our bounds, indicating that the simulation results might not hold asymptotically (similarly to what is now believed to have occurred in the real-space problem). We also apply our approach to random quantum circuits with random measurements, for which we can derive bounds transcending recent mappings to percolation problems. | mgoldstein@tauex.tau.ac.il | no | ||||

9 | Rmi Rhodes | Conformal Bootstrap in Liouville theory | Liouville field theory was introduced by Polyakov in the eighties in the context of string theory. Liouville theory appeared there under the form of a 2D Feynman path integral, describing fluctuating metrics over Riemann surfaces. Since then, this theory has been extensively studied in physics and this interest has more recently spread among the maths community. I will review recent works with G. Baverez, C. Guillarmou, A. Kupiainen and V. Vargas about a probabilistic construction of the path integral describing this theory. Then I will explain how it led to a rigorous formulation of the conformal bootstrap for the Liouville model. | remi.RHODES@univ-amu.fr | no | ||||

10 | Andrea Gamba | Politecnico di Torino | 2023-06-21 | 2023-06-30 | Phenomenological theory of self-organized molecular sorting | The cells of animals and plants contain a variety of membrane-bound organelles: mithocondria, lysosomes, endosomes, etc. Each such organelle plays a specific role, and its membrane has a special chemical composition. The specific chemical composition of each organelle is maintained by a self-organized process of molecular sorting, where specific molecules are distilled into submicrometric lipid vesicles, that are later delivered to the appropriate membrane regions. We have proposed a theoretical model of the process based on the coupling of spontaneous molecular aggregation and vesicle nucleation [1]. In the model, localized microdomains enriched in specific molecules form by phase separation on lipid membranes, grow by absorbing laterally diffusing molecules, and induce membrane bending and the nucleation of a lipid vesicle when they reach a characteristic size. Since the newly generated vesicle is constitutively enriched in the biochemical factors of the engulfed domain, this results in a natural distillation process. The efficiency of the process at the steady state is studied by means of a phenomenological theory, whose main parameters are the intermolecular aggregation strength and the number of molecules sorted per unit time. The theory predicts that the sorting process is most efficient in an intermediate, optimal range of the aggregation strength. In this optimal range, both the steady-state membrane concentration of sorted molecules and their average sorting time are minimal, and obey universal scaling laws. The predictions of the theory are verified numerically using a lattice-gas realization of the model. The results of experiments of molecular sorting in human endothelial cells support the hypothesis that the optimal sorting regime is actually realized in living cells, suggesting that it may have been evolutionary selected. [1] M. Zamparo, D. Valdembri, G. Serini, I.V. Kolokolov, V.V. Lebedev, L. Dall'Asta, A. Gamba, Optimality in self-organized molecular sorting. Phys. Rev. Lett. 126 (2021) 088101. | andrea.gamba@polito.it | no | |

11 | Eugenii Kuznetsov | P.N. Lebedev Physical Institute | Nonlinear dynamics of slipping ows | The process of breaking of inviscid incompressible flows along a rigid body with slipping boundary conditions is studied. Such slipping flows may be considered compressible on the rigid surface, where the normal velocity vanishes. It is the main reason for the formation of a singularity for the gradient of the velocity component parallel to rigid border. Slipping flows are studied analytically in the framework of two- and three-dimensional inviscid Prandtl equations. Criteria for a gradient catastrophe are found in both cases. For 2D Prandtl equations breaking takes place both for the parallel velocity along the boundary and for the vorticity gradient. For three-dimensional Prandtl flows, breaking, i.e. the formation of a fold in a fnite time, occurs for the symmetric part of the velocity gradient tensor, as well as for the antisymmetric part of vorticity. Simultaneously it leads to the formation of jets in perpendicular direction to the boundary that together with the vorticity blowup can be considered as the tornado type generation. The problem of the formation of velocity gradients for flows between two parallel plates is studied numerically in the framework of two-dimensional Euler equations. It is shown that the maximum velocity gradient grows exponentially with time on a rigid boundary with a simultaneous increase in the vorticity gradient according to a double exponential law. Careful analysis shows that this process is nothing more than the folding, with a power-law relationship between the maximum velocity gradient and its width: max |ux| ∝ ℓ^−2/3. This work was performed under financial support of the Russian Science Foundation (grant no. 19-72-30028) | kuznetso@itp.ac.ru | no | |||

12 | Gregory Falkovich | Weizmann Institute | Postmodern kinetics | Classical period of kinetics was when the kinetic equations were derived and their simple equilibrium and weakly non-equilibrium solutions were obtained. Modern period was proclaimed at seventies when it was discovered that the corrections to the kinetic equations diverge. These divergences (ring diagrams) were summed and the singular perturbation theory was established. Here I briefly describe how dramatically different is perturbation theory for far-from-equilibrium states like turbulence. | gregory.falkovich@weizmann.ac.il | no | |||

13 | Serguei Brazovskii | LPTMS, CNRS & Universit Paris-sud, Univ. Paris-Saclay, France | 2023-06-21 | 2023-06-30 | From chiral anomaly to two-fluid hydrodynamics for electronic vortices in charge density waves | no | |||

14 | Alexander D. Mirlin | Karlsruhe Institute of Technology, Germany | 2023-06-21 | 2023-06-30 | Generalized multifractality at 2D Anderson transitions | Critical states at Anderson transitions exhibit a remarkable property—multifractality. When understood in a narrow sense, the multifractality characterizes the scaling of eigenfunction moments. However, there is a much broader class of observables characterizing fluctuations and correlations of critical eigenstates. We use the term “generalized multifractality” (GM) for the scaling of such observables and the associated infinite set of exponents. In this talk based on [1, 2, 3, 4] I present fundamentals of GM and results for a number of 2D transitions. We have derived pure-scaling observables of GM for all symmetry classes of disordered systems. This is done in terms of composite operators in the sigma-model field theory and translated to the physically transparent language of eigenfunction observables. We have further verified this construction by numerical simulations of 2D network and tight-binding models in classes A and C [quantum-Hall (QH) and spin quantum Hall (SQH) transitions], in classes AII, D, DIII [metal-insulator transitions (MIT) and (thermal) metal phases], and in class AIII [MIT and critical-metal phase]. We have determined GM exponents by numerical simulations. For the SQH transition, we have also found a subset of these exponents analytically, by mapping to classical percolation. The analytical and numerical results are in excellent agreement with each other. Furthermore, they perfectly obey the Weyl symmetry that follows from properties of the sigma-model target space and relates scaling exponents of seemingly unrelated GM observables. Numerically obtained exponents at critical points of classes AII and AIII also satisfy the Weyl symmetry. At the same time, this symmetry is strongly violated at the MIT transitions of classes D and DIII, in agreement with analytical expectations based on the topology of the sigma-model manifolds (containing two disconnected components). We showed that, under the assumption of local conformal invariance, the spectrum of GM exponents satisfies “generalized parabolicity” (quadratic dependence on indices). In combination with the Weyl symmetry, this implies proportionality to eigenvalues of the quadratic Casimir operator. The analytical and numerical results for the SQH transition unambiguously demonstrate that the generalized parabolicity does not hold. This excludes Wess-Zumino-Novikov-Witten models, and, more generally, any theories with local conformal invariance, as candidates for the fixed-point theory of the SQH transition. Numerical results provide also strong evidence of violation of generalized parabolicity (and thus of local conformal invariance) at several other localization transitions in 2D systems. Implications of conformal invariance for GM at Anderson transitions in arbitrary spatial dimensionality are discussed in detail by I. Gruzberg in a related talk at Landau Week 2023. [1] J.F. Karcher, N. Charles, I.A. Gruzberg, A.D. Mirlin, Annals of Physics 435, 168584 (2021) [2] J. F. Karcher, I. A. Gruzberg, and A. D. Mirlin, Phys. Rev. B 105, 184205 (2022). [3] J. F. Karcher, I. A. Gruzberg, and A. D. Mirlin, Phys. Rev. B 106, 104202 (2022). [4] J. F. Karcher, I. A. Gruzberg, and A. D. Mirlin, Phys. Rev. B 107, 104202 (2023). | no | ||

15 | Alexander Gorsky | 2023-06-20 | 2023-06-27 | New findings in random regular graphs | The RRG ensemble plays two interesting roles - model of Hilbert space of interacting many-body systems and discrete model of 2d gravity. I will discuss the properties of the perturbed RRG from these two perspectives. First, I consider the properties of the RRG with node degree $d$ perturbed by chemical potentials $\mu_k$ for a number of short k-cycles and analyze both numerically and analytically the phase diagram of the model in the $(\mu_k,d)$ plane. The critical curve separating the homogeneous and clusterized phases is found and it is demonstrated that the clusterized phase itself generically is separated as the function of $d$ into the phase with ideal clusters and phase with coupled ones when the continuous spectrum gets formed. The eigenstate spatial structure of the model is investigated and it is found that there are localized scar-like states in the delocalized part of the spectrum, that are related to the topologically equivalent nodes in the graph. The Anderson transition for the case of combined ($k$-cycle) structural and diagonal (Anderson) disorders is investigated. The matrix model for massive spinless fermion on RRG with non-polynomial potential is found and solved in the planar approximation. New critical regime is found and interpolation between c=0 pure 2d gravity and c=-2 theories is identified. | shuragor@mail.ru | no | ||

16 | Ilya Gruzberg | Ohio University | 2023-06-20 | 2023-06-30 | Conformal invariance and Anderson transitions. | Anderson transitions (ATs) share many features with conventional second-order phase transitions in statistical mechanics, and it is natural to expect that conformal invariance should appear at the fixed points of ATs, giving us tools of conformal field theories to employ. However, ATs also exhibit unusual features, such as the absence of a natural order parameter, no upper critical dimension, and continuous families of critical exponents characterizing multifractal critical wave functions. Many properties of multifractal and generalized multifractal observables are known from their field-theoretic representation within supersymmetric sigma models, as discussed in the talk by A. Mirlin. In this talk I will review connections of multifractality to the question of conformal invariance at ATs, some history and examples highlighting these issues, as well as numerical and exact analytical results that provide growing evidence that many ATs do not exhibit conformal invariance in any spatial dimensionality, against expectations. | gruzberg.1@osu.edu | no | |

17 | Sergey Syzranov | Effect of quenched disorder on quantum spin liquids and geometrically frustrated magnets | We study the effects of quenched disorder on geometrically frustrated magnets (GFMs), the largest class of systems in which quantum spin liquids are sought. Quenched disorder may lead to the formation of the spin-glass state, incompatible with a quantum spin liquid, and also increases the magnetic susceptibility in GFMs. By analysing the available experimental data on the spin-glass freezing transition in GFMs, we demonstrate that, contrary to common intuition, decreasing impurity density in them increases the glass-transition temperature, i.e. makes random spin freezing more favourable! This behaviour challenges the existence of quantum spin liquids and implies the existence of a hidden energy scale independent of disorder and drives glass transitions in very clean GF materials. We develop a theory of glass transitions and magnetic susceptibility in GFMs with vacancy impurities, the most common type of quenched disorder in GFMs. We show that realistic GF lattices generically host low-energy excitations that lead to a crossover in a clean GF medium and a spin-glass-freezing transition with a temperature independent of disorder strength for realistic amounts of disorder. Diluting the GF medium with sparse vacancy defects lowers the glass-transitions temperature. Another consequence of the presence of vacancies is the creation of quasispins, effective magnetic moments localised near the vacancies, that contribute to the magnetic susceptibility of the system together with the bulk spins. We show that increasing the vacancy density leads to an increase in the total magnetic susceptibility. | sergey.syzranov@googlemail.com | no | ||||

18 | Andrea Cappelli | INFN and Physics Dept., Florence, Italy | 2023-06-21 | 2023-06-30 | Hydrodynamics from anomaly inflow | The Lagrangian formulation of perfect barotropic fluids can be recast into a bosonic effective field theory for fermions in 1+1 and 3+1 dimensions, which can describe the chiral and gravitational anomalies. This result is achieved by a reformulation of the hydrodynamic variational principle, which uses the anomaly inflow relation with a topological gauge theory in one extra dimension. | andrea.cappelli@fi.infn.it | no | |

19 | Yakov Fominov | L.D. Landau Institute for Theoretical Physics | 2023-06-26 | 2023-06-30 | Asymmetric higher-harmonic SQUID as a Josephson diode | We theoretically investigate asymmetric two-junction SQUIDs with different current-phase relations in the two Josephson junctions, involving higher Josephson harmonics. Our main focus is on the “minimal model” with one junction in the SQUID loop possessing the sinusoidal current-phase relation and the other one featuring additional second harmonic. The current-voltage characteristic (CVC) turns out to be asymmetric, . The asymmetry is due to the presence of the second harmonic and depends on the magnetic flux through the interferometer loop, vanishing only at special values of the flux such as integer or half-integer in the units of the flux quantum. The system thus demonstrates the flux-tunable Josephson diode effect (JDE), the simplest manifestations of which is the direction dependence of the critical current. We analyze asymmetry of the overall shape both in the absence and in the presence of external ac irradiation. In the voltage-source case of external signal, the CVC demonstrates the Shapiro spikes. The integer spikes are asymmetric (manifestation of the JDE) while the half-integer spikes remain symmetric. In the current-source case, the CVC demonstrates the Shapiro steps. The JDE manifests itself in asymmetry of the overall CVC shape, including integer and half-integer steps. [1] Ya.V. Fominov and D.S. Mikhailov, Phys. Rev. B 106, 134514 (2022). | fominov@itp.ac.ru | no | |

20 | Vladimir Gritsev | Integrable quantum many-body dynamics | I am going to discuss some solvable cases of quantum many-body systems. | vladgr23@gmail.com | no | ||||

21 | Mikhail Skvortsov | L.D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-28 | Inverted pendulum driven by a horizontal random force: statistics of the never-falling trajectory and supersymmetry | skvor@itp.ac.ru | no | ||

22 | Yuriy Makhlin | L.D. Landau Institute for Theoretical Physics | 2023-06-24 | 2023-06-30 | Majorana zero modes in a topological 2D Josephson junction | In a topological Josephson junction between two superconducting contacts on top of a 3D topological insulator, Majorana zero modes can be formed in an external magnetic field. These point-like modes are located periodically at Josephson vortices inside the junction. Their position can be controlled, and they can be used for topological quantum operations, using hybridization of nearby modes. We demonstrate that hybridization is prohibited by symmetries of the problem at vanishing chemical potential. This ensures additional protection of the Majorana zero modes, while controlled chemical potential allows one to vary the inter-mode tunnel coupling for quantum-information applications. | makhlin@itp.ac.ru | no | |

23 | Pavel Grigoriev | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-30 | Coexistence of superconductivity and charge/spin-density wave in organic metals | The interplay between superconductivity (SC) and spin/charge density wave (DW) in organic metals shows many similarities to high-Tc superconductors. It also contains many puzzles, for example, the anisotropic SC onset and the severalfold increase of the upper critical field Hc2 in the coexistence region, as well as the microscopic origin of SC/DW phase separation there. By the direct calculation of the Landau expansion for DW free energy, we argue [1] that the phase transition between DW and metallic/SC phase in organic superconductors goes by first order at low enough temperature, which explains the spatial segregation of DW and SC at large length scale, consistent with experimental observations. This first-order phase transition is not directly related to SC and happens even above the SC transition temperature. We also estimate the size of SC or DW islands obtained from the Ginzburg-Landau expansion for the DW free energy [2] and from analyzing the experimental data on anisotropic SC transition in thin samples [2,3]. [1] S.S. Seidov, V.D. Kochev, P.D. Grigoriev, arXiv /2305.06957 (sent to Phys. Rev. B). [2] V.D. Kochev, S.S. Seidov, P.D. Grigoriev, to be published. [3] V.D. Kochev, K.K. Kesharpu, P.D. Grigoriev, Phys. Rev. B 103, 014519 (2021 | grigorev@itp.ac.ru | no | |

24 | Dmytro Kiselov | L.D. Landau Institute For Theoretical Physics | 2023-06-22 | 2023-06-29 | Gapful electrons in a vortex core in granular superconductors | dmitrykiseliov2000@gmail.com | 16844953111684488605Kiselov_LandauWeek_abstract.pdf | ||

25 | Tigran Hakobyan | Yerevan St. University & Yerevan Phyics Institute | 2023-06-21 | 2023-06-30 | Z^{3} ⊗ Z^{3} symmetry protected topological paramagnets |
tigran.hakobyan@ysu.am | no | ||

26 | Tigran Sedrakyan | University of Massachusetts | 2023-06-21 | 2023-06-30 | Topological Order in Correlated Electron-Hole Bilayers | tsedrakyan@physics.umass.edu | no | ||

27 | Vladimir Lebedev | L. D. Landau Institute for Theoretical Physics | 2023-06-23 | 2023-06-30 | Coherent vortices in two-dimensional turbulence | burmi@itp.ac.ru | no | ||

28 | Sergey Vergeles | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-30 | Theoretical description of coherent geostrophic vortices and comparison with experiment | vergeles@gmail.com | no | ||

29 | Alexander Belavin | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-30 | Correlation numbers in Minimal Liouville gravity | sashabelavin@gmail.com | no | ||

30 | Vadim Geshkenbein | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-21 | Superconducting diodes, surface barriers and critical state of atomically thin superconductors | igor.burmistrov@googlemail.com | no | ||

31 | Michael Chertkov | University of Arizona | 2023-06-21 | 2023-06-24 | Universality and Control of Fat Tails | chertkov@math.arizona.edu | no | ||

32 | Igor Kolokolov | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | 2023-06-30 | Kinematic dynamo in chaotic flows | igor.kolokolov@gmail.com | no | ||

33 | Alexander Migdal | Turbulence as Clebsch Confinement | sasha.migdal@gmail.com | no | |||||

34 | Alexey Litvinov | L. D. Landau Institute for Theoretical Physics | 2023-06-21 | Integrable structures in N=2 conformal field theory and affine Yangian of gl(1|1) | My talk will be devoted to the study of affine Yangian symmetry and its applications in two-dimensional conformal field theory. I will consider a special class of integrable systems appearing in two-dimensional N=2 superconformal field theory (the main example being the N=2 quantum KdV system). Using the relation with the representation theory of affine Yangians, I will derive Bethe ansatz equations for the spectrum of integrals of motion. | litvinov@itp.ac.ru | no | ||

35 | Alexander Altland | Quantum chaos in two-dimensional gravity | alexal@thp.uni-koeln.de | no | |||||

36 | Emil Yuzbashyan | 2023-06-22 | 2023-06-27 | How strong can the electron-phonon interaction in metals be? | eyuzbash@physics.rutgers.edu | no | |||

37 | Natasha Kirova | LPS, CNRS & Université Paris-sud, Univ. Paris-Saclay, France | 2023-06-21 | 2023-06-30 | Combined fractional charge-spin vortices in spin density waves | As electronic crystals, the charge/spin density waves (CDW/SDW) possess such common topological defects as dislocations – the vortices of their displacements’ phases which appear under the application of the electric field or other stresses. Less commonly, the density waves possess also the space-time vortices, the phase slip centers as a kind of instantons, which are necessary for the onset of the collective sliding and the conversion among the normal and condensed carriers. SDWs, as itinerate antiferromagnets, possess also the spin-rotation degree of freedom which can give rise to vorticity of their staggered magnetization. The rich multiplicative order parameter of SDWs allows for an unusual object of a complex nature: topologically bound half - integer dislocation combined with a semi - vortex of a staggered magnetization [1,2]. These objects become energetically favorable in comparison with conventional integer vortices due to the enhanced Coulomb interactions. Their generation affects the static vortex arrays and also the timeperiodic phase slips responsible for the phenomenon of the so called narrow band noise. 1. S. Brazovskii and N. Kirova, “Phase slips, dislocations, half-integer vortices, two-fluid hydrodynamics and the chiral anomaly in charge and spin density waves.”, I.E. Dzyaloshinskii 90 anniversary volume, JETP, 159, 806-814 (2021). 2. S. Brazovskii and N. Kirova, “Simulations of dynamical electronic vortices in charge and spin density waves”, in “Topological Objects in Correlated Electronic Systems", MDPI Symmetry, 15 (2023) 915. | natacha.kirova@universite-paris-saclay.fr | 1685250397Kirova_Erevan_2023.pdf | |

38 | Dmitri Gangardt | 2023-06-21 | 2023-06-30 | Topological limit shape phase transitions: melting of Arctic Circles | gangardt@gmail.com | no | |||

39 | Andreas Kluemper | 2023-06-26 | 2023-06-30 | Logarithmic corrections arising from non-linear integral equations with singular kernels | kluemper@uni-wuppertal.de | 1685344294TitleAbstract.pdf | |||

40 | Igor Poboiko | Karlsruhe Institute of Technology, Germany | Theory of free fermions under random projective measurements | igor.poboiko@gmail.com | no |