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BEGIN:VEVENT
SUMMARY:Integrable matrix models in discrete space-time: A paradigm of Kar
dar-Parisi-Zhang physics
DTSTART;VALUE=DATE-TIME:20220330T120000Z
DTEND;VALUE=DATE-TIME:20220330T130000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-379@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Tomaz Prosen (University of Ljubljana)\nI will discu
ss a class of very simple integrable dynamics on a discrete space-time lat
tice\, which is generated by a 2-site matrix-valued rational map. \nThe ph
ase spaces of the matrix variable can be selected from diverse families of
symmetric spaces\, e.g. complex Grassmannians\, and are equipped with a n
atural symplectic structure.\nThis precise form of the map follows from a
simple consistency condition for a parallel transport (aka Lax zero curvat
ure condition) on a space-time lattice using \na minimalistic Lax operator
\, which is linear in the spectral and matrix variables. I will discuss th
e Yang-Baxter property and conservation laws of these maps.\n\nPhysically\
, the model represents an integrable discretization and SU(N) generalizati
on of Landau-Lifshitz magnet. Using numerical computations\, we have demon
strated that the\ntransport of Noether charges follows Kardar-Parisi-Zhang
universality with superdiffusive dynamical exponent 3/2. Most interesting
open questions will be discussed.\n\nhttps://konferenz.uni-hannover.de/ev
ent/36/contributions/379/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/379/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Universality and conformal invariance in percolation models
DTSTART;VALUE=DATE-TIME:20220330T150000Z
DTEND;VALUE=DATE-TIME:20220330T160000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-336@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Alexi Morin-Duchesne (Ghent University)\nIn this tal
k\, I will describe our investigations of the universal behaviour of two c
ritical percolation models: site percolation on the triangular lattice and
bond percolation on the square lattice. Both are Yang-Baxter integrable m
odels that can in principle be solved exactly. In the scaling limit\, they
are conformally invariant and described by non-unitary representations of
the Virasoro algebra. I will describe our calculation of the models' part
ition functions on the cylinder and torus. This is joint work with A. Klü
mper and P.A. Pearce.\n\nhttps://konferenz.uni-hannover.de/event/36/contri
butions/336/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/336/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lattice nonlinear Schroedinger equation and applications
DTSTART;VALUE=DATE-TIME:20220328T130000Z
DTEND;VALUE=DATE-TIME:20220328T141500Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-332@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Vladimir Korepin (Stony Brook University)\nQuantum l
attice nonlinear Schroedinger equation will be explained: history\, open p
roblems and applications [including nuclear physics].\n\nhttps://konferenz
.uni-hannover.de/event/36/contributions/332/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/332/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Generalized Hydrodynamics of the staircase model and higher spin c
urrents
DTSTART;VALUE=DATE-TIME:20220330T080000Z
DTEND;VALUE=DATE-TIME:20220330T083000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-337@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Michele Mazzoni (City University of London)\nThe sta
ircase model is an integrable modification of the sinh-Gordon model\, obta
ined by complexifying the coupling constant. A key feature of this theory
is the fact that the scaling function displays a roaming behaviour\, that
is\, it visits all the unitary minimal conformal models when varying the t
emperature. \nVia the generalized hydrodynamics (GHD) approach to iQFT\, w
e develop a more physical picture of interaction in the theory\, both at a
nd away from equilibrium\, relating this model to massless flows between c
onsecutive unitary minimal models.\nUsing this model as a case-study\, we
also investigate the average currents and densities of higher spin conserv
ed quantities in the partitioning protocol\, deriving a universal scaling
law which relates the spin to powers of the temperatures of the quenched s
ystems.\n\nhttps://konferenz.uni-hannover.de/event/36/contributions/337/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/337/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bipartite fidelity in the XXZ spin chain at the combinatorial poin
t
DTSTART;VALUE=DATE-TIME:20220330T130000Z
DTEND;VALUE=DATE-TIME:20220330T140000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-333@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Gilles Parez (CRM\, Université de Montréal)\nThe b
ipartite fidelity was introduced in 2011 by Stéphan and Dubail as an enta
nglement measure in quantum many-body systems. It is expressed in terms of
the overlap between the groundstate of the whole system and a tensor prod
uct of groundstates for two complementary subsystems. For one-dimensional
quantum critical systems\, the bipartite fidelity has an interpretation in
terms of conformal field theory (CFT)\, and its asymptotic behavior depen
ds on the conformal data of the underlying CFT.\n\nI will discuss the bipa
rtite fidelity for the XXZ spin chain at $\\Delta=-1/2$. The combinatorial
structure of the model allows us to derive exact finite-size expressions
for the overlaps\, and to investigate their asymptotic behavior. In partic
ular\, our results agree with the CFT predictions of Stéphan and Dubail.
This talk is based on arXiv:2111.15223\, in collaboration with Christian H
agendorf.\n\nhttps://konferenz.uni-hannover.de/event/36/contributions/333/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/333/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Unstable Excitations in an Integrable Quantum Field Theory
DTSTART;VALUE=DATE-TIME:20220328T120000Z
DTEND;VALUE=DATE-TIME:20220328T130000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-314@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Aleksandra Ziolkowska (University of Oxford)\nScatte
ring processes in integrable theories are traditionally associated with pa
rticle number conservation. This is indeed the case for asymptotic states\
, yet at intermediate time-scales decaying excitations are allowed. The fa
mily of homogeneous sine-Gordon (HSG) models provides a rare example of an
integrable quantum field theory where both stable and unstable bound stat
es are present in the spectrum.\n\nIn my talk\, I will present a study of
a particular member of this family\, the $SU(3)_2$-HSG model\, following a
non-equilibrium quench. At high temperatures\, physical intuition suggest
s that unstable particles are constantly formed and destroyed\, and thus e
xist in finite proportions. As such\, they may be expected to have a stron
g effect on the dynamics far from equilibrium and at finite densities. Ado
pting the generalized hydrodynamic approach\, we identified the key signat
ures of unstable excitations which may serve as hallmarks for the finite-l
ived bound states formation. Furthermore\, we explored in considerable det
ail quantitative and qualitative dependence of the instability signatures
on the quench parameters.\n\nhttps://konferenz.uni-hannover.de/event/36/co
ntributions/314/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/314/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hydrodynamic description of multispecies TASEP
DTSTART;VALUE=DATE-TIME:20220329T100000Z
DTEND;VALUE=DATE-TIME:20220329T110000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-312@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Ali Zahra ()\nExclusion processes in one dimension f
irst appeared in the 70's and have since dragged much attention from commu
nities in different domains: stochastic processes\, out of equilibriums st
atistical physics and more recently integrable systems. While it is well k
nown that the hydrodynamic limit of the single species totally asymmetric
simple exclusion process (TASEP) is described by the Burger's equation\, m
uch less is known for multispecies generalizations\, which present a much
richer phenomenology. In this talk we shall present results for a version
of the TASEP\, containing two species of particles and a hierarchical dyna
mic depending on two parameters. By using results for the stationary measu
re of such model on ring domains\, we shall formulate the conservations la
ws associated to the different kind of particles. We show an explicit non-
linear decoupling of those equations which allows an in-depth discussion o
f their solutions (shocks\, Riemann problem\, etc.). Good agreement is fou
nd with numerical simulations.\n\nhttps://konferenz.uni-hannover.de/event/
36/contributions/312/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/312/
END:VEVENT
BEGIN:VEVENT
SUMMARY:3D Chern-Simons gravity and osp(1|2) CFT
DTSTART;VALUE=DATE-TIME:20220328T143000Z
DTEND;VALUE=DATE-TIME:20220328T150000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-331@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Juan Ramos Cabezas (Ariel University)\nIn this talk\
, I will talk about the holographic description of the osp(1|2) super conf
ormal blocks on the sphere and the torus. I will concentrate on the 2-poin
t and 3-point conformal blocks on the sphere and the 1-point and 2-point b
locks on the torus. I will present some results we have obtained in a work
in process (to be published soon). It is known that the holomorphic part
of primary superfields can be decomposed into two ordinary primary fields
(the even (bosonic) and odd part (fermionic))\, thus we can express the ge
neral correlation functions in terms of these ordinary primary fields (the
obtained terms we call them component of the correlation functions). I wi
ll show how these components of the correlation functions can be obtained
from the 3D Chern-Simons theory context. This idea of computing the confor
mal blocks from the 3D Chern-Simon theory has been proposed and developed
(for some specific algebras\, e.g. the sl(2) and sl(3) algebras ) in some
previous works of one the authors and other authors\, in this talk I will
talk about the case of the osp(1|2) algebra.\n\nhttps://konferenz.uni-hann
over.de/event/36/contributions/331/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/331/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dynamics of charge-imbalance-resolved entanglement negativity afte
r a quench in a free-fermion model
DTSTART;VALUE=DATE-TIME:20220331T070000Z
DTEND;VALUE=DATE-TIME:20220331T080000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-325@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Riccarda Bonsignori (Ruder Boskovic Institute (Zagre
b))\nThe presence of a global internal symmetry in a quantum many-body sys
tem is reflected in\nthe fact that the entanglement between its subparts i
s endowed with an internal structure\, namely\nit can be decomposed as sum
of contributions associated to each symmetry sector. The study of\nthe sy
mmetry resolution of entanglement measures provides a formidable tool to p
robe the outof-\nequilibrium dynamics of quantum systems. \nAs presented i
n the previous edition of this Workshop by my collaborator Gilles Parez\,
we initiated the study of the time evolution of the symmetry-resolved enta
nglement entropy after a global quench in the context of free-fermion syst
ems. In this talk\, I will present the results of our subsequent study of
the time evolution of its counterpart for non-complementary subsystems\, n
amely the charge-imbalance-resolved negativity\, in the same setting. We f
ind that the charge-imbalance-resolved logarithmic negativity shows an eff
ective equipartition in the scaling limit of large times and system size\,
with a perfect equipartition for early and infinite times. We also derive
and conjecture a formula for the dynamics of the so-called charged\nRény
i logarithmic negativities. We argue that our results can be understood in
the framework of\nthe quasiparticle picture for the entanglement dynamics
\, and provide a conjecture that we expect\nto be valid for generic integr
able models.\n\nhttps://konferenz.uni-hannover.de/event/36/contributions/3
25/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/325/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Weak integrability breaking and level spacing distribution
DTSTART;VALUE=DATE-TIME:20220330T093000Z
DTEND;VALUE=DATE-TIME:20220330T100000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-315@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Dávid Szász-Schagrin (Budapest University of Techn
ology and Economics\, Statistical Field Theory Research Group)\nRecently i
t was suggested that certain perturbations of integrable spin chains lead
to a weak breaking of integrability in the sense that integrability is pre
served at the first order in the coupling. Here we examine this claim usin
g level spacing distribution. We find that the volume dependent crossover
between integrable and chaotic level spacing statistics which marks the on
set of quantum chaotic behaviour\, is markedly different for weak vs. stro
ng breaking of integrability. In particular\, for the gapless case we find
that the crossover coupling as a function of the volume $L$ scales with a
$1/L^{2}$ law for weak breaking as opposed to the $1/L^{3}$ law previousl
y found for the strong case.\n\nhttps://konferenz.uni-hannover.de/event/36
/contributions/315/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/315/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Riemann surfaces for the totally asymmetric exclusion process with
open boundaries
DTSTART;VALUE=DATE-TIME:20220329T093000Z
DTEND;VALUE=DATE-TIME:20220329T100000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-326@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Ulysse Godreau (Laboratoire de Physique Théorique -
Université Toulouse III)\nThe totally asymmetric exclusion process (TASE
P) is a continuous time Markov process much studied in statistical physics
featuring particle with hard-core interaction hopping randomly on a one d
imensional lattice.\nThis talk will focus on the study of the fluctuations
of the particle current in the TASEP with open boundaries in the thermody
namic limit. More precisely\, the eigenvalues of a deformation of the Mark
ov matrix of the process\, connected to the cumulant generating function o
f the current\, are computed in two different ways. The first excited stat
es are recovered from the ground state eigenvalue (obtained by matrix prod
uct ansatz) by analytic continuation. They are then compared with the asym
ptotics of the Bethe ansatz equations. The eigenstates are put in correspo
ndance with the sheets of a Riemann surfaces\, which is the maximal domain
of definition of the analytic continuation of the ground states. Connecti
ons are made with KPZ universality and previous results on the TASEP with
periodic boundary conditions.\nThis work was done in collaboration with Sy
lvain Prolhac (LPT Toulouse)\n\nhttps://konferenz.uni-hannover.de/event/36
/contributions/326/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/326/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integrability breaking in the one dimensional Bose gas: Atomic los
ses and energy loss
DTSTART;VALUE=DATE-TIME:20220330T083000Z
DTEND;VALUE=DATE-TIME:20220330T090000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-316@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Arthur Hutsalyuk (Eötvös Loránd University (ELTE)
)\nThe one dimensional δ-function interacting Bose gas (the Lieb-Liniger
model) is an integrable system\, which can model experiments with ultra co
ld atoms in one dimensional traps. Even though the model is integrable\, i
ntegrability breaking effects are always present in the real world experim
ents. In this work we consider the integrability breaking due to atomic lo
ss\, which is the most relevant effect in the experiments. We set up a fra
mework for the exact computation of the losses of the canonical charges of
the model\, and compute an exact result for the energy loss due to the lo
cal K-body processes\, valid for arbitrary K.\n\nhttps://konferenz.uni-han
nover.de/event/36/contributions/316/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/316/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ergodicity of dual unitary permutation circuits
DTSTART;VALUE=DATE-TIME:20220331T093000Z
DTEND;VALUE=DATE-TIME:20220331T100000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-317@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Márton Borsi (Eötvös Loránd University\, Budapes
t)\nOne class of exactly solvable quantum many-body systems is the set of
dual unitary quantum circuits\, whose fundamental quantum gate is also uni
tary in the space direction. In these models the infinite temperature dyna
mical correlation functions can be calculated exactly both for integrable
and chaotic systems. For local dimension N=2 the complete classification i
s known\, and multiple general construction procedures were studied in the
case of higher N. One special class is formed by classical cellular autom
ata corresponding to cases when the quantum gate is simply a permutation.
Our recent study with Balázs Pozsgay focused on these models and led to s
ome unexpected results. The presence of conserved quantities induces non-e
rgodic behaviour\, which we studied by investigating the recurrence time.
We found models lacking the Yang-Baxter integrability structure but still
possessing an infinite number of charges. We also observed that maximally
chaotic circuits can show signs of non-ergodicity if they are constructed
from a linear map over finite fields.\n\nhttps://konferenz.uni-hannover.de
/event/36/contributions/317/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/317/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Solvable models in discrete space-time
DTSTART;VALUE=DATE-TIME:20220329T120000Z
DTEND;VALUE=DATE-TIME:20220329T130000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-349@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Balázs Pozsgay ()\nWe will discuss models on discre
te 1+1 dimensional space-time\, which display different versions of solvab
ility. The models include both classical and quantum mechanical systems. T
he two main mechanisms underlying solvability are the traditional forms of
integrability\, and the more recent idea of dual unitarity. We will explo
re these ideas and survey a number of different integrable models.\n\nhttp
s://konferenz.uni-hannover.de/event/36/contributions/349/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/349/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Folded XXZ model and hard rod deformations
DTSTART;VALUE=DATE-TIME:20220330T100000Z
DTEND;VALUE=DATE-TIME:20220330T110000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-318@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Levente Pristyák ()\nIntegrable models are special
quantum many-body systems because they posses a large number of conserved
charges\, which enables one to treat these models with analytic tools. How
ever\, in usual integrable systems (e.g. XXZ model) certain computations -
for example the calculation of correlation functions - are very difficult
to tackle exactly. Therefore in recent years \,\,simpler'' integrable mod
els were constructed and treated. In my talk I will consider one such syst
em\, the so called folded XXZ model. I will present some results regarding
the dynamics of this system and its connection to hard rod deformations a
nd other simple integrable systems.\n\nhttps://konferenz.uni-hannover.de/e
vent/36/contributions/318/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/318/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On the critical behaviour of the inhomogeneous six-vertex model
DTSTART;VALUE=DATE-TIME:20220329T070000Z
DTEND;VALUE=DATE-TIME:20220329T080000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-320@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Gleb Kotousov (DESY)\nThe inhomogeneous six-vertex m
odel is a multi-parametric integrable 2D statistical system. With the anis
otropy parameter |q|=1\, the model is critical and is expected to exhibit
a variety of interesting universal behaviour. In this talk we discuss the
scaling limit of the homogeneous and so-called staggered cases and mention
some applications to QFT. We also describe a conjecture from arXiv:2106.0
1238 that predicts the critical behaviour of the general inhomogeneous six
-vertex model and its spin J = 1\, 3/2\, 2\, … generalizations in a cert
ain regime of the anisotropy q.\n\nhttps://konferenz.uni-hannover.de/event
/36/contributions/320/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/320/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integrability and Yangian Symmetry in 4-dimensional QFTs
DTSTART;VALUE=DATE-TIME:20220328T100000Z
DTEND;VALUE=DATE-TIME:20220328T110000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-321@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Julian Miczajka (Max-Planck-Institut fuer Physik)\nI
n this talk I provide an overview on the appearance of integrability - esp
ecially in the form of Yangian symmetry - in the context of several diffe
rent quantities in four-dimensional quantum field theories. In particular\
, I discuss how superconformal Yangian symmetry shows up in different form
s in the context of planar N=4 super-Yang-Mills (SYM) theory\, whose spect
ral problem famously maps to an integrable spin-chain. \nI proceed by desc
ribing how these structures leave imprints on more generic quantum field t
heories. Recently\, it was found that Yangian symmetry survives certain do
uble-scaling deformations of planar N=4 SYM theory\, and shows up in certa
in ubiquitous classes of massless and massive Feynman integrals. I sketch
how we connected these surprising symmetry structures to a - presumably in
tegrable - massive fishnet theory and how they can be used to set up a boo
tstrap algorithm that allows to calculate the integrals from scratch.\n\nh
ttps://konferenz.uni-hannover.de/event/36/contributions/321/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/321/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The relevant excitations for the one-body function in the Lieb-Lin
iger model
DTSTART;VALUE=DATE-TIME:20220328T093000Z
DTEND;VALUE=DATE-TIME:20220328T100000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-323@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Felipe Sant'Ana (Faculty of Physics\, University of
Warsaw)\nWe study the ground state one-body correlation function in the Li
eb-Liniger model. In the spectral representation\, correlations are built
from contributions stemming from different excited states of the model. We
aim to understand which excited states carry significant contributions\,
specifically focusing on the small energy-momentum part of the dynamic one
-body function. We conjecture that relevant excitations take form similar
to two-spinon states known from XXZ spin chain. We validate this hypothesi
s by numerical evaluation of the correlator with ABACUS algorithm and by a
nalytical computations in the strongly interacting regime.\n\nhttps://konf
erenz.uni-hannover.de/event/36/contributions/323/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/323/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Symmetry resolved entanglement in excited states in QFT
DTSTART;VALUE=DATE-TIME:20220331T080000Z
DTEND;VALUE=DATE-TIME:20220331T090000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-324@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Lucia Santamaria-Sanz (University of Valladolid)\nIn
this talk the excess entanglement resulting from exciting a finite number
of quasiparticles above the ground state of a free integrable quantum fie
ld theory in 1+1D with an internal U(1) symmetry will be studied. It will
be shown both for bosons and fermions theories that the ratio of charged m
oments between the excited and ground states take a extremely simple and u
niversal form depending on the number and statistics of the excitations an
d on the charges associated to the underlying U(1) symmetry. The formulae
obtained for this ratio of charged moments can be numerically checked for
some lattice models.\n\nhttps://konferenz.uni-hannover.de/event/36/contrib
utions/324/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/324/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integrability as a new method for exact results on quasinormal mod
es of black holes
DTSTART;VALUE=DATE-TIME:20220328T150000Z
DTEND;VALUE=DATE-TIME:20220328T160000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-327@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Daniele Gregori (University of Bologna)\nIn this tal
k\, I will show a new connection we found between quantum integrable model
s and black holes perturbation theory. After a brief introduction to quasi
normal modes and their role in gravitational waves observations\, I will c
onnect their mathematically precise definition with the integrability stru
ctures derived from the differential equation associated to the black hole
perturbation. More precisely\, I will derive the full system of functiona
l and non linear integral equations (Thermodynamic Bethe Ansatz) typical o
f quantum integrability and prove that the quasinormal modes verify differ
ent equivalent exact quantization conditions. As a consequence\, it follow
s a new simple and effective method to numerically compute quasinormal mod
es\, namely the Thermodynamic Bethe Ansatz\, which I will compare with oth
er methods. I will also give a mathematical explanation of the recently fo
und connection between quasinormal modes and N=2 supersymmetric gauge theo
ries\, through the further connection we previously found of these to quan
tum integrable models. All this I will show for a generalization of extrem
al Reissner-Nordström (charged) black holes\, but in the end I will expla
in how it should be possible to generalize it to many other black holes\,
branes\, fuzzballs\, etc. and thus provide a new effective tool for the st
udy of quantum gravity and gravitational waves. (Based on: ArXiv:2112.114
34)\n\nhttps://konferenz.uni-hannover.de/event/36/contributions/327/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/327/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sausage Model and the Generalised Hydrodynamic Formalism
DTSTART;VALUE=DATE-TIME:20220331T120000Z
DTEND;VALUE=DATE-TIME:20220331T123000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-329@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Mario Flores ()\nOn this talk we'll review the basic
concepts of non-linear sigma models and in \nparticular the one-parameter
integrable deformation of the 2d O(3) sigma model. \nWe'll explore the so
lutions of this system via thermodynamic bethe ansatz\, Y-systems and Dynk
in TBA and how to apply this techniques on a Field theory as the one we ar
e dealing with here. \n In the second part of this presentation we'll cons
truct a partition protocol with two semi-infinite\, disconnected\, reservo
irs at different temperatures at $t_{0}$ that became connected at some la
ter time $t$ that realize non-equilibrium states on the sausage model. We
'll discuss the numerical results of this simulation.\n\n Furthermore\, th
e deformed O(3) sigma model exhibits an outstanding characteristic that wi
ll be stress during the talk: \nits duality with sine-Liouville theory and
its interpretation as a 2d black hole.\n\nhttps://konferenz.uni-hannover.
de/event/36/contributions/329/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/329/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anomalous fluctuations in integrable systems
DTSTART;VALUE=DATE-TIME:20220329T133000Z
DTEND;VALUE=DATE-TIME:20220329T143000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-313@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Žiga Krajnik (University of Ljubljana)\nWe discuss
anomalous fluctuations recently observed in the (anisotropic) Landau-Lifhs
itz model in equilibrium\, a paradigmatic integrable model of interacting
classical spins. Typical fluctuations of the time-integrated spin current
on sub-ballistic scales are non-Gaussian and the cumulants are found to gr
ow with different (algebraic) exponents\, unlike in the "standard" scenari
o of the theory of large deviations\, where the existence of a scaled cumu
lant generating functions implies finite scaled cumulants.\n\nSimilar phen
omenology is observed in a simple interacting cellular automaton\, where a
n analytical computation of the full counting statistics is feasible. Asym
ptotic analysis of the exact solution gives access to the current distribu
tion on all scales and explicit cumulant asymptotics. The scaled cumulant
generating function does not generate scaled cumulants. Our findings hint
at novel types of dynamical universality classes in deterministic many-bod
y systems.\n\n 1. Ž. Krajnik\, E. Ilievski\, T. Prosen\, *Absence of Norm
al Fluctuations in an Integrable Magnet*\, arXiv:[2109.13088][1] (2021)\n
2. Ž. Krajnik\, J. Schmidt\, V. Pasquier\, E. Ilievski\, T. Prosen\, *Exa
ct anomalous current fluctuations in a deterministic interacting model*\,
arXiv:[2201.05126][2] (2022)\n\n [1]: https://arxiv.org/abs/2109.13088\n
[2]: https://arxiv.org/abs/2201.05126\n\nhttps://konferenz.uni-hannover.d
e/event/36/contributions/313/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/313/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bound state production in the 1d Bose gas
DTSTART;VALUE=DATE-TIME:20220328T080000Z
DTEND;VALUE=DATE-TIME:20220328T090000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-322@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Rebekka Koch ()\nOut-of-equilibrium phases of matter
have triggered a lot of attention in the last decade\, since new and inte
resting physical phenomena with no equilibrium counter parts can arise. Th
e 1d interacting Bose-gas for example possesses bound states for attractiv
e interactions but is experimentally highly unstable at equilibrium. Howev
er\, these bound states become stable out-of-equilibrium since the 1d Bose
-gas is integrable and thus\, thermalization is absent. \nStrongly interac
ting systems are notoriously hard to tackle\, but due to integrability we
can analytically investigate slow interaction changes from the repulsive t
o the attractive regime using the framework of Generalized Hydrodynamics (
GHD). We obtain exact predictions for the bound state production and compl
etely characterize the non-equilibrium state.\nWhile in the quantum realm
numerical checks are often absent\, we can translate this protocol to the
semi-classical analogue of the 1d Bose-gas – the non-Linear-Schroedinger
equation (NLS) – and exploit Monte Carlo methods for numerical benchma
rks. By taking the semi-classical limit new technical challenges arise\, b
ut they are accompanied with new insight into the thermodynamical descript
ion of the NLS model.\nFinally\, as the 1d interacting Bose-gas is realize
d in state-of-the art experiments with cold atoms\, our analytic results c
an already be applied to describe signatures of bound-states.\n\nhttps://k
onferenz.uni-hannover.de/event/36/contributions/322/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/322/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Measurement catastrophes in quantum jammed states
DTSTART;VALUE=DATE-TIME:20220331T100000Z
DTEND;VALUE=DATE-TIME:20220331T110000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-328@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Saverio Bocini (LPTMS - Université Paris-Saclay)\nL
ocal measurements can sometimes lead to unexpected macroscopic behaviours.
Such “measurement catastrophes” in integrable models go beyond genera
lized hydrodynamics\, that is arguably the most effective large-scale desc
ription of dynamics in integrable models in the presence of inhomogeneitie
s. A noteworthy occurrence of this phenomenon is found in systems exhibiti
ng quantum jamming. I will provide a simple and solvable example by consid
ering a particular class of the jammed states of the large-anisotropy limi
t of the Heisenberg magnet. That will allow me to present the microscopic
dynamics behind the emergence of ballistic profiles of local observables f
ollowing a local measurement in that particular model.\n\nhttps://konferen
z.uni-hannover.de/event/36/contributions/328/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/328/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Absence of string excitations in the low-T spectrum of the quantum
transfer matrix of the XXZ chain
DTSTART;VALUE=DATE-TIME:20220330T140000Z
DTEND;VALUE=DATE-TIME:20220330T143000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-319@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Saskia Faulmann (Bergische Universität Wuppertal)\n
The eigenvalues of the quantum transfer matrix (QTM) of the XXZ spin-1/2 c
hain in the Trotter limit are parameterized by solutions of non-linear int
egral equations (NLIEs). We analyze these equations in the low-temperature
limit for the model in the antiferromagnetic massless regime at finite ma
gnetic field. To leading order in T the solutions of the NLIEs are determi
ned by the dressed energy\, which\, in turns\, is the solution of a linear
Fredholm integral equation of the second kind. A rigorous characterizatio
n of the properties of the dressed energy in different regions of the comp
lex plane\, in conjuction with a thorough study of the subsidiary conditio
ns that determine the excitation parameters in the solutions of the NLIEs\
, allows us to show that the excited states of the QTM are all of particle
-hole type and that there are no string excitation in the low-T limit\, as
long as the magnetic field is kept finite.\n\nhttps://konferenz.uni-hanno
ver.de/event/36/contributions/319/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/319/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ballistic Fluctuation theory: correlation functions and entangleme
nt entropy
DTSTART;VALUE=DATE-TIME:20220330T070000Z
DTEND;VALUE=DATE-TIME:20220330T080000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-330@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Giuseppe Del Vecchio Del Vecchio (King’s College L
ondon)\nIn integrable models when an operator couples to a conserved charg
e its decay will be algebraic along rays in spacetime due to few-body scat
tering processes giving rise to 'sound waves' ballistically propagating. T
here are example of operators that do not produce these waves but still en
code fundamental information. Remarkable examples are the so called twist
fields\, present whenever there is an internal symmetry. Twist fields are
responsible for exponential decay of order parameter dynamical correlation
functions in spin chains and are directly related to entanglement entropy
. Ballistic Fluctuation Theory(BFT) is the theory of large deviations for
ballistic transport. When a conserved charge is transported through the sy
stem\, Euler equations for macroscopic densities and currents give a hydro
dynamic description of the quasi-particle excitations. For integrable mode
ls BFT provides an exact expression of current fluctuations which in turn
determine the spacetime behavior of correlations of the aforementioned twi
st fields. As a simple demonstration\, I will show the application of thes
e ideas to two cases: the calculation of dynamical correlation functions o
f order parameters in the XX model and computation of entanglement entropi
es in free theories. If time allows I will sketch the more complicated sit
uation of interacting theories.\n\nhttps://konferenz.uni-hannover.de/event
/36/contributions/330/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/330/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The open U(sl(2))-invariant staggered six-vertex model and the CFT
behind it
DTSTART;VALUE=DATE-TIME:20220329T080000Z
DTEND;VALUE=DATE-TIME:20220329T090000Z
DTSTAMP;VALUE=DATE-TIME:20240224T162824Z
UID:indico-contribution-36-334@konferenz.uni-hannover.de
DESCRIPTION:Speakers: Sascha Gehrmann ()\nThe finite-size spectrum of the
critical alternating Z2-staggered spin-1/2 XXZ model with quantum group in
variant boundary conditions is presented. For all values of the staggering
parameter the continuum limit has been found to be described in terms of
the non-compact SU(2\, R)/U(1) Euclidean black hole conformal field theory
(CFT) whose scaling dimensions include a continuous component. In additio
n\, we find that levels from the discrete part of the spectrum of this CFT
emerge as the anisotropy is varied. The finite size amplitudes of both th
e continuous and the discrete levels are related to the corresponding eige
nvalues of a quasi-momentum operator which commutes with the Hamiltonian a
nd the transfer matrix of the model.\n\nhttps://konferenz.uni-hannover.de/
event/36/contributions/334/
LOCATION:
URL:https://konferenz.uni-hannover.de/event/36/contributions/334/
END:VEVENT
END:VCALENDAR