Speaker:   Jiasheng Liu
Title:   Breaking and emergence of universality in spin wave turbulence
Abstract:   Turbulence of weakly interacting waves displays a great deal of universality: independence of the pumping and dissipation scales and of the details of the interaction. We discuss how an inverse cascade (from large to small wavenumbers) of spin waves evolves from weak to strong turbulence. The next- to-leading-order correction to the kinetic equation exhibits explicit dependence on the pumping scale, signaling UV nonlocality. As a result, the Kolmogorov-Zakharov description of spin-wave turbulence breaks down at a wavenumber parametrically larger than that at which spectrally local interaction becomes strong. We paraphrase this as: nonlocality enhances nonlinearity. We then discuss strong turbulence in a multi-component extension of the model. We argue that strong turbulence of spin waves realizes the state of critical balance between dispersion and nonlinearity. In such a state, UV nonlocality causes the turbulence level at large scales to decrease as the flux increases, culminating in a state independent of the flux but dependent on the pumping scale.
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Speaker:   Guido Boffetta
Title:   Butterfly effect and predictability in turbulence
Abstract:   I will review the predictability problem in fully developed turbulence. In particular I will discuss how the Lyapunov exponent depends on the Reynolds number and examine the role of intermittency, both in 3D Navier-Stokes turbulence and in Surface Quasi-Geostrophic flow, a model for mesoscale geophysical flows. I will also analyze the evolution of localized perturbations and their effects on flow predictability.
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Speaker:   Nir Navon
Title:   Core-bound waves on a Gross-Pitaveskii vortex
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Speaker:   Gilbert Weinstein

Abstract:  
The no-hair theorem asserts that stationary, asymptotically flat vacuum black holes are described by the Kerr family, parametrized by mass and angular momentum. Under an analyticity assumption, Hawking’s rigidity theorem yields axial symmetry. For axially symmetric solutions with a single connected event horizon, Robinson (1975) proved that the solution must be Kerr. The possibility of equilibrium configurations with multiple black holes, however, has remained largely open. In this talk, we show that stationary, axially symmetric multiple black holes cannot be in equilibrium. The proof uses harmonic maps with prescribed singularities. We will emphasize the geometric ideas behind this result and explain how a differential inequality and the maximum principle enter the argument. This is joint work with Qing Han, Marcus Khuri, and Jingang Xiong.

Speaker:   Alexei Maliybaev
Title:   Perturbative anomalous exponents from Kolmogorov multipliers
Abstract:   Intermittency, manifested through anomalous scaling, remains one of the central unresolved problems in turbulence theory, with few analytical approaches extending beyond idealized linear transport models. We introduce a perturbative framework for anomalous scaling in turbulent transport based on multiplier statistics, rather than zero-mode calculations. We demonstrate the approach using a shell model combining deterministic and Kraichnan-like stochastic components. We reduce the problem to the analysis of a stationary Fokker-Planck equation for Kolmogorov multipliers, defined as ratios of successive scalar amplitudes. Its solution yields the invariant measure through a perturbative expansion around a Gaussian distribution. Using the resulting multiplier statistics, we compute explicit anomalous scaling exponents for structure functions of arbitrary order, including odd, even, and non-integer moments. Although demonstrated here for a shell model, the framework suggests a systematic perturbative route toward analytical theories of intermittency in turbulence. This is a joint work with Simon Thalabard.
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Speaker:   Nigel Goldenfeld
Title:   Stochastic theory for laminar-turbulence transition, pattern formation and front propagation in pipe flow
Abstract:   How do fluids become turbulent as their flow velocity is increased? In recent years, careful experiments in pipes and Taylor-Couette systems have revealed that the lifetime of transient turbulent regions in a fluid appears to diverge with flow velocity just before the onset of turbulence, faster than any power law or exponential function. I show how this superexponential scaling of the turbulent lifetime in pipe flow is related to extreme value statistics, which I show is a manifestation of a mapping between transitional turbulence and the statistical mechanics model of directed percolation. This mapping itself arises from a further surprising and remarkable connection: turbulence and emergent mean flows in a pipe behave as a predator-prey ecosystem. In new work, I show that the "ecological" model of transitional turbulence, when extended to include streamwise interactions, not only describes the transitional phenomena, but also the series of four distinct states --- decaying puffs, splitting puffs, weak slugs, strong slugs --- that lead to fully-developed turbulence. Work performed in collaboration with: Hong-Yan Shih, Tsung-Lin Hsieh and Xueying Wang
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Speaker:   Luca Biferale
Title:   Data-driven Modeling of Eulerian and Lagrangian Turbulence
Abstract:   We present different stochastic generative frameworks for the generation and augmentation of complex, multiscale signals arising in Eulerian and Lagrangian turbulence. The approach builds on generative Diffusion Models, a class of probabilistic deep learning methods capable of learning high-dimensional data distributions beyond Gaussian approximations.
We demonstrate applications to both three-, two- and one-dimensional stochastic signals, including the temporal evolution of turbulent observables along Lagrangian trajectories. The proposed methodology is benchmarked against Gaussian Process Regression using complementary statistical diagnostics and pointwise error metrics. Particular emphasis is placed on the faithful reproduction of non-Gaussian statistics, intermittency, extreme events, and scale-dependent correlations.
We further present preliminary results on the generalization to memorization transition.
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Speaker:   Guru Jayasingh
Title:   Laminar-turbulent transition in pipes with body forces: continuous, discontinuous or both?
Abstract:   The laminar-turbulent transition in straight pipes is believed to be driven by activator-inhibitor dynamics between zonal flows and small-scale turbulence, leading generically to a continuous non-equilibrium phase transition in the directed percolation universality class. However, in curved pipes or in the presence of body forces it is possible to observe a discontinuous transition and other phenomenology which seem inconsistent with the emerging consensus. Here, we consider the perturbing effects of body forces and incorporate them into a minimal Landau theory of the transition. We calculate the phase diagram as a function of Reynolds number and body force strength, and show that above a threshold strength of the latter, there is a tricritical point which accounts for the observed discontinuity behavior, including spatially heterogeneous states. Our results are consistent with experiments in centrifugal pipes and recently also in stratified flows.
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Speaker:   Snehanshu Maiti
Title:   Eulerian–Lagrangian Relations in Decaying Two-Dimensional Navier–Stokes Turbulence
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Speaker:   Hrant Hakobyan

Abstract:  
The conformal dimension of a metric space is the infimum of the Hausdorff dimensions of its quasisymmetric images. A space is called minimal if its Hausdorff dimension cannot be lowered by such maps. In this talk, I will present recent joint work with Ilia Binder and Wen-Bo Li proving that the graph of one-dimensional Brownian motion is almost surely minimal, with conformal dimension 3/2. The proof combines Brownian local time with Fuglede’s modulus of measures and families of subsets of conformal dimension one. Related methods also establish minimality for Bedford–McMullen carpets with uniform fibers.

Speaker:   Daniel Lecoanet
Title:   Internal Waves in Turbulent Convective / Stably-Stratified Systems
Abstract:   Most studies of turbulent convection consider a fluid confined between two solid horizontal boundaries. However, in nature, convection regions are often adjacent to stably-stratified regions. Here we study how turbulent convection can excite internal waves in an adjacent stably-stratified medium. I will present theoretical and numerical calculations showing that the wave energy spectrum is related to a fourth-order correlation function of the turbulent velocities. I will discuss applications of this theory to both non-rotating and rotating convection.
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Speaker:   Miguel Bustamante
Title:   Triad phase dynamics determine cascade direction in two-dimensional turbulence.
Abstract:   Despite their importance in turbulence theory, a unifying and predictive rule determining the direction of the cascades of conserved quantities is lacking. In this work, we show that the direction of the cascades in two-dimensional turbulence is encoded in the complex phases of the Fourier transform of the velocity field. We develop a closure for the dynamics of a triad phase, the sum of the phases of three modes forming a triad, based on the observation that neighboring triad phases are weakly correlated. The resulting stochastic model can be solved analytically to find the triad phase probability distribution function (PDF). We validate the model's assumptions and predictions using an ensemble of two-dimensional turbulence simulations. From the triad phase PDF we develop a closure of the energy equation, and prove that the cascade directions are determined by the model without adjustable parameters and given only the energy spectrum. Triad phase dynamics occur in any quadratically nonlinear partial differential equation, making this a promising new direction in the study of strongly out-of-equilibrium systems. This is joint work with Santiago Benavides.
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Title:   Ballistic Transport and Drude Weight
Speaker:   Andreas Klümper
Abstract:   Transport phenomena are commonly described in terms of Ohm’s law and its extensions to time-dependent fields and dynamical conductivities. A particularly interesting regime is ballistic transport, in which currents persist without decay and dissipation is absent. Such behavior occurs in a variety of physical systems and is intimately related to conservation laws. For non-relativistic gases, the particle current operator is proportional to the total momentum, implying strictly ballistic particle transport. In this simple setting, the Drude weight admits two natural representations, one of which is expressed in terms of current fluctuations. I will discuss these formulations and explain why they are equivalent in canonical ensembles, while this equivalence need not persist in more general equilibrium states, such as generalized Gibbs ensembles. I will then turn to spin transport in the anisotropic spin-1/2 Heisenberg (XXZ) chain. Here, the notion of ballistic transport raises some subtle questions. In particular, I will discuss the interplay between the thermodynamic and long-time limits and how the resulting Drude weight may depend on the order in which these limits are taken.

Title:   Asymptotic analysis of form factor series for the
Lieb-Liniger Bose gas
Speaker:   Frank Göhmann
Abstract:   I will reflect on the problem of extracting the long-time
large-distance asymptotic behaviour of integrable models
from different form factor series expansions. Over the past
years we have pursued two different directions: direct
resummation and Riemann-Hilbert analysis. I will present
recent results on the Riemann-Hilbert analysis of the
Fredhom determinant of a generalized sine-kernel that
will allow us to analyse several two-point functions of the
Lieb-Liniger Bose gas. As a first concrete result I will present
new asymptotic formulae for the field-field correlators
of the impenetrable Bose gas in thermal and non-thermal
equlibrium and show that they are numerically efficient.

Speaker:   Renzo Ricca

Title:   Topological Hydrodynamics

Title:   Hydrodynamic decoupling and recoupling
Speaker:   Sarang Gopalakrishnan
Abstract:   TBD

Speaker:   Yash Deshmukh

Abstract:  
TBA

Title:   From Fractal Drude Weights to Full Counting Statistics: Integrable Transport in the Quantum Sine-Gordon Model
Speaker:   Gábor Takács
Abstract:   Integrable quantum many-body systems are generically characterized by ballistic transport due to their extensive sets of conservation laws. However, their fine-grained transport properties often exhibit subtle anomalous structures driven by the internal symmetries of quasiparticle scattering. In this talk, I will overview our results on the thermodynamic and hydrodynamic description of the quantum sine-Gordon field theory at generic couplings. We show that topological charge transport exhibits singular, fractal-like Drude weights and an interplay with diffusive processes driven by non-diagonal kink–antikink scattering. Finally, we demonstrate that these fractal features carry over to the full counting statistics (FCS) of conserved charges and their currents.

Title:   Dissipative dynamics with decoupled Bogoliubov hierarchies
Speaker:   Fabian Essler
Abstract:   TBD

Title:   Peaked Solitons in Integrable Systems
Speaker:   Zhijun Qiao
Abstract:   In this talk, I will introduce some integrable scalar models which possess peaked solitons (peakons), including the well-known Camassa-Holm (CH), the Degasperis-Procesi (DP), and other new peakon equations developed in recent years. I will take the CH case as a typical example to explain the details and show that the Camassa-Holm spectral problem yields two different integrable hierarchies of nonlinear evolution equations. In particular, the CH peakon equation is able to be extended to the DP, the b-family, the FORQ, the Novikov, the modified CH (MoCH), and other higher order models with peakons or pseudo-peakons. Open problems will also be addressed for discussion in the end. Part of work is joint with Dr. Baoqiang Xia and Dr. Enrique Reyes.

Title:   Tail-State RG Improvement for Hamiltonian Truncation in Sine-Gordon and Related Models
Speaker:   Marton Lajer
Abstract:   Numerical precision spectroscopy in perturbed conformal field theories provides an independent route for testing results from integrability. Hamiltonian truncation represents the interacting Hamiltonian in a finite-dimensional space of low-energy states of the unperturbed theory, with the dominant systematic error arising from the omitted high-energy Hilbert space.
Existing RG-improvement schemes partially account for these states, but either approximate the resulting nonlocal corrections using a limited number of OPE channels, or become computationally expensive when the full nonlocal contribution is retained. I will present a tail-state RG improvement for the compact boson that uses level-sum recursions to evaluate these finite-cutoff nonlocal corrections directly, without constructing the full high-energy Hilbert space, while preserving a manifestly variational formulation. Applied to sine-Gordon and multifrequency sine-Gordon models, the method substantially improves cutoff convergence over conventional OPE-based RG improvement, with the full cubic correction in some regimes differing significantly from its local approximation. The GPU-adapted algorithm applies to both eigenvalues and matrix elements, including highly excited states.

Title:   Sequential Circuit as Generalized Symmetry on Lattice
Speaker:   Xie Chen
Abstract:   Generalized symmetry extends the usual notion of symmetry to ones that are of higher form, acting on subsystems, non-invertible, etc. The concept was originally defined in the field theory context using the idea of topological defects. In this talk, we show that on the lattice, generalized symmetries are realized by a special type of quantum circuit called the Sequential Quantum Circuits. We show how to obtain the full, potentially non-invertible symmetry action from the unitary sequential circuit and how the connection to the sequential circuit constrains the properties of the generalized symmetries. Matrix product operator and Tensor product operator representations play an important role in our discussion.

Title:   Strong Zero Modes in Supersymmetry-Inspired Quantum Circuits
Speaker:   Kareljan Schoutens
Abstract:   We investigate discrete dynamics in quantum circuits with 2-qubit gates corresponding to the S-matrix of an integrable supersymmetric 1+1D quantum field theory. For a brick-wall configuration such circuits support both localized and delocalized dynamically conserved operators known as strong zero modes (SZM), the number of which depends on the parameter regime. While some of the SZM remain localized at boundaries, other SZM can be guided to propagate across the circuit, inspiring protocols for quantum information transport.

Speaker:   Theodore Drivas

Title:   Mathematics of turbulence part 2

Title:   Symmetry Enforced Entanglement From Projective Generalized Symmetries
Speaker:   Ho Tat Lam
Abstract:   The celebrated Lieb-Schultz-Mattis theorem dictates that projective symmetry forces a many-body system to possess long-range entanglement. In this talk, we will discuss the consequence of projective generalized symmetries on many-body entanglement. Surprisingly, unlike ordinary projective symmetries, projective generalized symmetries do not always enforce long-range entanglement. Nevertheless, when long-range entanglement is not required, the symmetries can still enforce non-trivial short-range entanglement and a nontrivial symmetry protected topological order.

Title:   Signatures of Topological Symmetries on a Noisy Quantum Simulator
Speaker:   Ananda Roy
Abstract:   Topological symmetries, invertible and otherwise, play a fundamental role in the investigation of quantum field theories. Despite their ubiquitous importance across a multitude of disciplines ranging from string theory to condensed matter physics, controlled realizations of models exhibiting these symmetries in physical systems are rare. Quantum simulators based on engineered solid-state devices provide a novel alternative to conventional condensed matter systems for realizing these models.
In this work, eigenstates of impurity Hamiltonians and loop operators associated with the topological symmetries for the Ising conformal field theory in two space-time dimensions are realized on IBM's Kingston simulator. The relevant states are created on the quantum device using a hybrid quantum-classical algorithm. The latter is based on a variation of the quantum approximate optimization algorithm ansatz combined with the quantum natural gradient optimization method. Signatures of the topological symmetry are captured by measuring correlation functions of different qubit operators with results obtained from the quantum device in reasonable agreement with those obtained from classical computations. The current work demonstrates the viability of noisy quantum simulators as platforms for investigating low-dimensional quantum field theories with direct access to observables that are often difficult to probe in conventional condensed matter experiments.

Title:   The c-d conjecture
Speaker:   German Sierra
Abstract:   We propose the c-d conjecture, which relates the long-distance degrees of freedom of a critical quantum chain to its microscopic local Hilbert space. For a unitary, local, nearest-neighbour Hamiltonian with local dimension d, whose low-energy limit is described by a conformal field theory of central charge c, the conjecture states that c <= d-1. We discuss its physical interpretation in terms of short- and long-range entanglement and examine its consistency with a variety of integrable spin chains, fermionic systems and anyonic models, as well as its extension to random critical chains. Finally, we introduce finite-size lattice c-functions constructed from lattice realizations of the Virasoro generators and test them in several critical and non-critical models.

Title:   Parastatistics in Interacting Periodic Chains Revealed by Peierls Phase Twists and Shifted Conformal Towers
Speaker:   Dirk Schuricht
Abstract:   We consider interacting paraparticle chains with a constant R matrix where the Hamiltonian sums over the internal degrees (flavors) of the paraparticles. For such flavor-blind Hamiltonians, we show a general factorization of the Hilbert space into occupation and flavor parts with the Hamiltonian acting nontrivially only on the former. For open boundaries, the spectrum therefore coincides with that of the occupation Hamiltonian with the flavor part merely adding degeneracies. For periodic boundaries, a cyclic reordering of the flavors leads to a separation of the occupation Hamiltonian into flux sectors at fixed particle number, thus making the parastatistics directly observable in the energy spectrum. For important exemplary cases, the occupation Hamiltonian reduces to the XXZ chain with flux, allowing for an exact solution. In the gapless regime, this solution shows flux-shifted conformal towers in the low-energy spectrum and a temperature-dependent chemical potential in the bulk thermodynamics.

Speaker:   Conghan Dong

Title:   Quintic Ginzburg-Landau description of M(2,7) minimal model
Speaker:   Andrei Katsevich
Abstract:   My talk will be devoted to Ginzburg-Landau descriptions of non-unitary minimal models. I will discuss dimensional continuation of the massless scalar field theory with the iφ^5 interaction term. It preserves the so-called PT symmetry, which acts by φ → −φ accompanied by i → −i. Below its upper critical dimension 10/3, this theory has interacting infrared fixed points. I will argue that the fixed point in d = 2 describes the non-unitary minimal conformal model M(2,7). I identify the operators φ and φ^2 with the Virasoro primaries φ_{1,2} and φ_{1,3}, respectively, and iφ^3 with a quasi-primary operator, which is a Virasoro descendant of φ_{1,3}. These identifications appear to be consistent with the operator product expansions and with considerations based on integrability. Using constrained Pade extrapolations, it can be obtained estimates of the critical exponents in d = 3. I will also comment on possible lattice descriptions of M(2,7) and discuss RG flows to and from this CFT. Finally, I will conjecture that the minimal models M(2,2n+1) are described by the massless scalar field theories with the iφ^{2n−1} interaction terms.

Title:   Charge gap in quantum many-body systems
Speaker:   Masaki Oshikawa
Abstract:   TBD

Title:   Quantum Algorithms for Classical Fluid Dynamics
Speaker:   Joe Bhaseen
Abstract:   Recent advances have shown the potential for quantum algorithms in the
numerical simulation of classical fluid dynamics. The use of tensor
networks allows for the compression of classical data and the
possibility of efficient simulation. Here we discuss recent work on the
solution of the discretised Navier-Stokes equation. We discuss the
potential for practical applications.

Title:   Thermodynamics of the quantum Nagle-Kardar model
Speaker:   Andrea Trombettoni
Abstract:   We study the thermodynamic phase diagram of a one-dimensional quantum spin chain subjected to both mean-field and nearest-neighbor interactions, and to a transverse magnetic field . The purpose is to determine the effect of the quantum fluctuations, due to the transverse field, on the phase diagram, in particular with respect to the occurrence of ensemble inequivalence. We denote our model as a quantum Nagle-Kardar model. To perform the calculation of the canonical partition function, we show that, due to the presence of the mean-field term, in the thermodynamic limit one can use the Hubbard-Stratonovich transformation in spite of the non-commutativity of the different operators appearing in the Hamiltonian, and we adopt a procedure of successive approximations that lead to the determination of the phase diagram thanks to a scaling property of the phase transition lines. The results show that the ensemble inequivalence, present in the classical Nagle-Kardar model, is removed above a threshold value hc for the transverse field. For h larger than hc the phase diagram exhibits only second-order phase transition lines, implying therefore restoration of ensemble equivalence.

Title:   Limit shapes in measured many-particle quantum states in the large deviation regime
Speaker:   Jerome Dubail
Abstract:   TBD

Title:   Tractable model for a fractionalized Fermi liquid (FL$^*$) on
a square lattice
Speaker:   Alexei Tsvelik
Abstract:   Motivated by the continued interest in Fermi-surface reconstruction without symmetry breaking, we present an analytically tractable microscopic model of a fractionalized Fermi liquid (FL$^*$) on a square lattice and discuss its potential relevance to the cuprates. As in ancilla-qubit constructions, the model is related to Kondo lattice systems, but in this case, the conduction electrons interact with a $\mathbb{Z}_2$ spin liquid of the Yao--Lee type, with a Majorana Fermi surface. The associated $\mathbb Z_2$ gauge theory is static so that the model can be analytically solved to leading-logarithic accuracy. There are two phases: one in which the fractionalized fermions of the spin liquid hybridize with conduction electrons to form a common Fermi surface violating the naive Luttinger count, and one in which they remain decoupled. We discuss the salient features of the small Fermi-surface phase, including analytically derived momentum dependent coherence factors responsible for the appearance of Fermi arcs \`{a} la Yang-Rice-Zhang. We further discuss the impact of quantum and thermal fluctuations, including a strong diamagnetic response and a logarithmically divergent Sommerfeld coefficient at the onset of the pseudogap.

Title:   Symmetry-enhanced entanglement detection
Speaker:   Fei Yan
Abstract:   Entanglement depth, measuring the size of the largest entangled cluster in a quantum state, serves as a critical benchmark for validating quantum resources and has important applications in quantum metrology and quantum computing. While quantum Fisher information (QFI) has been shown to provide bounds on entanglement depth, existing criterion is often modest in certifying entanglement in real materials. In this talk, I will introduce sharpened QFI bounds which can certify entanglement depth more efficiently, utilizing symmetries that are already present in the underlying quantum system. I will also describe the application of such improved QFI bounds in neutron scattering experiments of quantum magnets.

Speaker:   Jason Starr

Abstract:  
For a family of smooth, projective varieties over a curve such that one fiber is a Fano complete intersection, does there exist a rational section of the family? In joint work with Zhiyu Tian we strengthen our earlier work with Ruhong Zong: there exist rational sections whenever the characteristic is at least as large as the degrees of the defining equations (of course this implies the characteristic zero case). We also prove new cases of "weak approximation", i.e., there exist enough rational sections to approximate power series / Laurent series sections to arbitrary order. For instance, this holds when the characteristic equals 0 and at least one fiber is "2-Fano": both the first and second graded pieces of the Chern character are positive.

Title:   Quantum computational resources in integrable models: non-Gaussianity, CFT, and noninvertible symmetry
Speaker:   Yuto Ashida
Abstract:   ‘Correlatedness’ plays a key role in many disciplines of condensed matter physics, but it remains largely unexplored how one can precisely quantify the degree of correlation in a given many-body state. In this talk, I will approach this question from both quantum information and condensed matter perspectives. Specifically, we provide an information-theoretic measure to quantify the non-Gaussianity of a fermionic/bosonic many-body state and reveal its universal aspects for a 1D critical state through the lens of CFT. We then give a unified perspective for non-Gaussianity and nonstabilizerness, which allows us to provide analytical predictions of their universal behaviors. I will present tensor network calculations of the prototypical integrable models (fermionic XXZ and Ising models) that validate these predictions. Time permitting, I will also talk about how nonstabilizerness measure can encode fusion rules of conformal defects, which might be useful to probe noninvertible symmetries.

Title:   Universal energy-space localization and stable quantum phases against time-dependent perturbations
Speaker:   Tzu-Chieh Wei
Abstract:   Stability against perturbations is a defining property of quantum many-body phases of matter. However, most rigorous stabilities are only established for static perturbations; whether any system can remain stable against generic time-dependent perturbations is largely elusive. Here, we identify a universal phenomenon, where the evolving state driven by time-dependent q-local Hamiltonians can be exponentially localized in an energy window of instantaneous spectrum, and prove its survival under generic time-dependent perturbations. Applying such energy-space localization to classical and quantum LDPC codes whose codewords are separated by extensive energy barriers, we show that the system remains localized near the original codeword for an exponentially long time under generic time-dependent perturbations. For classical optimization problems with clustered solution spaces, the stability becomes an obstacle for quantum Hamiltonian-based algorithms to escape local minima. Our work provides a new lens for analyzing quantum non-equilibrium dynamics and tools for establishing stability and designing quantum algorithms.

Speaker:   Theodore Drivas
Title:   Mathematics of turbulence - Part 2

Title:   DMRG in the generalized Landau paradigm
Speaker:   Frank Verstraete
Abstract:   TBD

Title:   A toy model for entanglement spreading in diffusive systems
Speaker:   Vincenzo Alba
Abstract:   TBD

Title:   Quantum multicritical point with non-invertible symmetries in a simple spin chain
Speaker:   Nathanan Tantivasadakarn
Abstract:   I will construct a simple qubit spin chain with Rep(D₈) symmetry and discuss exact and numerical results of the phase diagram, including evidence that it hosts a multicritical point connecting all gapped phases with this symmetry.

Title:   Proliferation of non-invertible symmetries in the Q-state Potts model
Speaker:   Arkya Chatterjee
Abstract:   TBD

Title:   Observing quantum criticality at finite temperature through nonanalytic correlation times
Speaker:   Marton Kormos
Abstract:   I will report recent results on the finite-temperature dynamical correlation function of the magnetization operator in the quantum Ising spin chain. Using methods based on hydrodynamic fluctuations, I will show that the decay rate exhibits non-analytic behavior as the magnetic field, space-time direction, and temperature are varied. As a function of the magnetic field, the non-analyticity occurs at a value that continuously approaches the zero-temperature quantum critical point as the velocity is decreased. Inside the light cone, it reaches the critical point itself, where we find a new, temperature-independent logarithmic divergence. I will argue that the same phenomenon also occurs in the interacting sine-Gordon field theory. These results demonstrate that collective effects induced by quantum fluctuations can persist in the dynamics of local observables even at finite temperature.

Title:   Quantum hard rods: a minimal model for complex quantum gases
Speaker:   Miłosz Panfil
Abstract:   The classical gas of hard rods has long served as a simple and exactly solvable model in the statistical physics of interacting particles. In contrast, its quantum counterpart has attracted relatively little attention. In this talk, I will argue that, while computationally simpler, the quantum hard-rod model exhibits a level of complexity comparable to the Lieb–Liniger model, which has been a fundamental exactly solvable quantum gas for over 60 years. I will support this claim by presenting our recent results on the exact dynamic correlation functions, non-equilibrium dynamics and Fermi-Bose hard rods mixtures.

Title:   Correlation and entanglement dynamics of free fermions in disguise
Speaker:   Juan Pablo Bayona Pena
Abstract:   We study the nonequilibrium dynamics following a quantum quench in spin chains that can be solved via a mapping to free fermions in disguise. These models feature an exponential degeneracy of all energy eigenvalues, raising the question of the validity of the established framework describing the properties of integrable systems out of equilibrium. We present two main results. First, we develop an analytic method to compute the quasi-momentum distribution function characterizing the generalized Gibbs ensemble, and derive an analytic formula to compute the corresponding expectation values for special observables. Second, we adapt the standard formula for the entanglement growth based on the quasi-particle picture, discussing how our constructions do not explicitly make use of the zero-energy auxiliary free fermions responsible of the exponential degeneracies. We test our theoretical predictions against numerical tensor-network computations for different initial states and Hamiltonian parameters. For the local observables, we find excellent agreement. For the entanglement dynamics, we find small deviations suggesting that the standard quasi-particle picture is only approximately correct for the initial state considered. Our results represent a first step towards the extension of the established framework of integrable systems out of equilibrium to models hosting free fermions in disguise.

Speaker:   Adi Glucksam

Abstract:  
TBA