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BEGIN:VEVENT
SUMMARY:Martin Hairer (Imperial College London)
DTSTART:20200505T130000Z
DTEND:20200505T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/1
DESCRIPTION:Title: The Brownian castle\nby Martin Hairer (Imperial College L
ondon) as part of One world IAMP mathematical physics seminar\n\nAbstract:
TBA\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Philip Solovej (University of Copenhagen)
DTSTART:20200512T130000Z
DTEND:20200512T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/2
DESCRIPTION:Title: Universality in the structure of atoms and molecules\nby
Jan Philip Solovej (University of Copenhagen) as part of One world IAMP ma
thematical physics seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Clavier (University of Potsdam)
DTSTART:20200519T130000Z
DTEND:20200519T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/3
DESCRIPTION:Title: Borel-Ecalle resummation for a Quantum Field Theory\nby P
ierre Clavier (University of Potsdam) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nBorel-Ecalle resummation of resurgent fu
nctions is a vast generalisation of the well-known Borel-Laplace resummati
on method. It can be decomposed into three steps: Borel transform\, averag
ing and Laplace transform. I will start by a pedagogical introduction of e
ach of these steps. To illustrate the feasability of the Borel-Ecalle resu
mmation method I then use it to resum the solution of a (truncated) Schwin
ger-Dyson equation of a Wess-Zumino model. This will be done using known r
esults about this Wess-Zumino model as well as Sauzin's analytical bounds
on convolution of resurgent functions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sven Bachmann (University of British Columbia)
DTSTART:20200526T130000Z
DTEND:20200526T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/4
DESCRIPTION:Title: Adiabatic quantum transport\nby Sven Bachmann (University
of British Columbia) as part of One world IAMP mathematical physics semin
ar\n\n\nAbstract\nIn the presence of a spectral gap above the ground state
energy\, slowly driven condensed matter systems may exhibit quantized tra
nsport of charge. One of the earliest instances of this fact is the Laughl
in argument explaining the integrality of the Hall conductance. In this ta
lk\, I will discuss transport by adiabatic processes in the presence of in
teractions between the charge carriers. I will explain the central role pl
ayed by the locality of the quantum dynamics in two instances: the adiabat
ic theorem and an index theorem for quantized charge transport. I will als
o relate fractional transport to the anyonic nature of elementary excitati
ons\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihalis Dafermos (Cambridge University)
DTSTART:20200602T130000Z
DTEND:20200602T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/5
DESCRIPTION:Title: The nonlinear stability of the Schwarzschild metric without s
ymmetry\nby Mihalis Dafermos (Cambridge University) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nI will discuss an upco
ming result proving the full finite-codimension non-linear asymptotic stab
ility of the Schwarzschild family as solutions to the Einstein vacuum equa
tions in the exterior of the black hole region. No symmetry is assumed. Th
e work is based on our previous understanding of linear stability of Schwa
rzschild in double null gauge. Joint work with G. Holzegel\, I. Rodnianski
and M. Taylor.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Winter (Universitat Autònoma de Barcelona)
DTSTART:20200609T130000Z
DTEND:20200609T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/6
DESCRIPTION:Title: Energy-constrained diamond norms and the continuity of channe
l capacities and of open-system dynamics\nby Andreas Winter (Universit
at Autònoma de Barcelona) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nThe channels\, and more generally superoperators ac
ting on the trace class operators of a quantum system naturally form a Ban
ach space under the completely bounded trace norm (aka diamond norm). Howe
ver\, it is well-known that in infinite dimension\, the norm topology is o
ften "too strong" for reasonable applications. Here\, we explore a recentl
y introduced energy-constrained diamond norm on superoperators (subject to
an energy bound on the input states). Our main motivation is the continui
ty of capacities and other entropic quantities of quantum channels\, but w
e also present an application to the continuity of one-parameter unitary g
roups and certain one-parameter semigroups of quantum channels.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicola Pinamonti (University of Genova)
DTSTART:20200616T130000Z
DTEND:20200616T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/7
DESCRIPTION:Title: Equilibrium states for interacting quantum field theories and
their relative entropy\nby Nicola Pinamonti (University of Genova) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nDuring
this talk we will review the construction of equilibrium states for inter
acting\nscalar quantum field theories\, treated with perturbation theory\,
recently proposed by\nFredenhagen and Lindner.\nWe shall in particular se
e that this construction is a generalization of known\nresults valid in th
e case of C*-dynamical systems. We shall furthermore discuss some properti
es \nof these states and we compare them with known results in the physica
l literature.\nIn the last part of the talk\, we shall show that notions l
ike relative entropy or entropy\nproduction can be given for states which
are of the form discussed in the first part of talk.\nWe shall thus provid
e an extension to quantum field theory of similar concepts available\nin t
he case of C*-dynamical systems.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nilanjana Datta (University of Cambridge)
DTSTART:20200623T130000Z
DTEND:20200623T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/8
DESCRIPTION:Title: Discriminating between unitary quantum processes\nby Nila
njana Datta (University of Cambridge) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nDiscriminating between unknown objects i
n a given set is a fundamental task in experimental science. Suppose you a
re given a quantum system which is in one of two given states with equal p
robability. Determining the actual state of the system amounts to doing a
measurement on it which would allow you to discriminate between the two po
ssible states. It is known that unless the two states are mutually orthogo
nal\, perfect discrimination is possible only if you are given arbitrarily
many identical copies of the state.\n\nIn this talk we consider the task
of discriminating between quantum processes\, instead of quantum states. I
n particular\, we discriminate between a pair of unitary operators acting
on a quantum system whose underlying Hilbert space is possibly infinite-di
mensional. We prove that in contrast to state discrimination\, one needs o
nly a finite number of copies to discriminate perfectly between the two un
itaries. Furthermore\, no entanglement is needed in the discrimination tas
k. The measure of discrimination is given in terms of the energy-constrain
ed diamond norm and one of the key ingredients of the proof is a generaliz
ation of the Toeplitz-Hausdorff Theorem in convex analysis. Moreover\, we
employ our results to study a novel type of quantum speed limits which ap
ply to pairs of quantum evolutions.This work was done jointly with Simon
Becker (Cambridge)\, Ludovico Lami (Ulm) and Cambyse Rouze (Munich)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laure Saint-Raymond (ENS Lyon)
DTSTART:20200630T130000Z
DTEND:20200630T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/9
DESCRIPTION:Title: Fluctuation theory in the Boltzmann-Grad limit\nby Laure
Saint-Raymond (ENS Lyon) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nIn this talk\, I will discuss a long term project wit
h T. Bodineau\, I. Gallagher and S. Simonella on hard-sphere dynamics in t
he kinetic regime\, away from thermal equilibrium. \n\nIn the low density
limit\, the empirical density obeys a law of large numbers and the dynamic
s is governed by the Boltzmann equation. \n\nDeviations from this behavior
are described by dynamical correlations\, which can be fully characterize
d for short times. This provides both a fluctuating Boltzmann equation and
large deviation asymptotics.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Despré\;s (Sorbonne University)
DTSTART:20200707T130000Z
DTEND:20200707T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/10
DESCRIPTION:Title: Spectral-scattering theory and fusion plasmas\nby Bruno
Despré\;s (Sorbonne University) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nMotivated by fusion plasmas and Tokamaks
(ITER project)\, I will describe recent efforts on adapting the mathemat
ical theory of linear unbounded self-adjoint operators (Kato\, Lax\, Reed-
Simon\, ....) to problems governed by kinetic equations coupled with Maxw
ell equations.\n\nFirstly it will be shown that Vlasov-Poisson-Ampere equa
tions\, linearized around non homogeneous Maxwellians\, can be written in
the framework of abstract scattering theory (linear Landau damping is a co
nsequence). Secondly the absorption principle applied to the hybrid resona
nce will be discussed.\n\nAll results come from long term discussions and
collaborations with many colleagues (Campos-Pinto\, Charles\, Colas\, Heur
aux\, Imbert-Gérard\, Lafitte\, Nicolopoulos\, Rege\, Weder\, and many ot
hers).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hal Tasaki (Gakushuin University)
DTSTART:20200714T130000Z
DTEND:20200714T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/11
DESCRIPTION:Title: 'Topological' index and general Lieb-Schultz-Mattis theorems
for quantum spin chains\nby Hal Tasaki (Gakushuin University) as part
of One world IAMP mathematical physics seminar\n\n\nAbstract\nA Lieb-Schu
ltz-Mattis (LSM) type theorem states that a quantum many-body system with
certain symmetry cannot have a unique ground state accompanied by a nonzer
o energy gap. While the original theorem treats models with continuous U(
1) symmetry\, new LSM-type statements that only assume discrete symmetry h
ave been proposed recently in close connection with topological condensed
matter physics. Here we shall prove such general LSM-type theorems by usin
g the "topological" index intensively studied in the context of symmetry p
rotected topological phase. Operator algebraic formulation of quantum spin
chains plays an essential role in our approach. Here I do not assume any
advanced knowledge in quantum spin systems or operator algebra\, and illus
trate the ideas of the proof (which I believe to be interesting).\n
\nT
he talk is based on a joint work with Yoshiko Ogata and Yuji Tachikawa in
arXiv:2004.06458.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolas Rougerie (University of Grenoble Alpes)
DTSTART:20200728T130000Z
DTEND:20200728T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/12
DESCRIPTION:Title: Two modes approximation for bosons in a double well potentia
l\nby Nicolas Rougerie (University of Grenoble Alpes) as part of One w
orld IAMP mathematical physics seminar\n\n\nAbstract\nWe study the mean-fi
eld limit for the ground state of bosonic particles in a double-well poten
tial\, jointly with the limit of large inter-well separation/large potenti
al energy barrier. Two one-body wave-functions are then macroscopially occ
upied\, one for each well. The physics in this two-modes subspace is usual
ly described by a Bose-Hubbard Hamiltonian\, yielding in particular the tr
ansition from an uncorrelated "superfluid" state (each particle lives in b
oth potential wells) to a correlated "insulating" state (half of the parti
cles live in each potential well). \n\nThrough precise energy expansions
we prove that the variance of the number of particles within each well is
suppressed (violation of the central limit theorem)\, a signature of a co
rrelated ground state. \n\nQuantum fluctuations around the two-modes descr
iption are particularly relevant\, for they give energy contributions of t
he same order as the energy difference due to suppressed variances in the
two-modes subspace. We describe them in terms of two independent Bogoliubo
v Hamiltonians\, one for each potential well.\n\nJoint work with Alessandr
o Olgiati and Dominique Spehner\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hugo Duminil-Copin (IHES / University of Geneva)
DTSTART:20200721T130000Z
DTEND:20200721T140000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/13
DESCRIPTION:Title: Marginal triviality of the scaling limits of critical 4D Isi
ng and &phi\;_4^4 models\nby Hugo Duminil-Copin (IHES / University of
Geneva) as part of One world IAMP mathematical physics seminar\n\n\nAbstra
ct\nIn this talk\, we will discuss the scaling limits of spin fluctuations
in four-dimensional Ising-type models with nearest-neighbor ferromagnetic
interaction at or near the critical point are Gaussian and its implicatio
ns from the point of view of Euclidean Field Theory. Similar statements wi
ll be proven for the &lambda\;&phi\;4 fields over R^4 with a lattice ultra
violet cutoff\, in the limit of infinite volume and vanishing lattice spac
ing. The proofs are enabled by the models' random current representation\,
in which the correlation functions' deviation from Wick's law is expresse
d in terms of intersection probabilities of random currents with sources a
t distances which are large on the model's lattice scale. Guided by the an
alogy with random walk intersection amplitudes\, the analysis focuses on t
he improvement of the so-called tree diagram bound by a logarithmic correc
tion term\, which is derived here through multi-scale analysis.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antti Kupiainen (University of Helsinki)
DTSTART:20200908T140000Z
DTEND:20200908T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/14
DESCRIPTION:Title: Integrability of Liouville Conformal Field Theory\nby An
tti Kupiainen (University of Helsinki) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nA. Polyakov introduced Liouville Confor
mal Field theory (LCFT) in 1981 as a way to put a natural measure on the s
et of Riemannian metrics over a two dimensional manifold. Ever since\, the
work of Polyakov has echoed in various branches of physics and mathematic
s\, ranging from string theory to probability theory and geometry. In the
context of 2D quantum gravity models\, Polyakov’s approach is conje
cturally equivalent to the scaling limit of Random Planar Maps and through
the Alday-Gaiotto- Tachikava correspondence LCFT is conjecturally related
to certain 4D Yang-Mills theories. Through the work of Dorn\,Otto\, Zamol
odchikov and Zamolodchikov and Teschner LCFT is believed to be to a certai
n extent integrable. \n\nI will review a probabilistic construction of LCF
T developed together with David\, Rhodes and Vargas and recent proofs conc
erning the integrability of LCFT: \n-The proof in a joint work with Rhodes
and Vargas of the DOZZ formula (Annals of Mathematics\, 81-166\,191 (2020
) \n-The proof in a joint work with Guillarmou\, Rhodes and Vargas of the
bootstrap conjecture for LCFT (arXiv:2005.11530).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Victor Ivrii (University of Toronto)
DTSTART:20200915T140000Z
DTEND:20200915T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/15
DESCRIPTION:Title: Scott and Thomas-Fermi approximations to electronic density<
/a>\nby Victor Ivrii (University of Toronto) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nIn heavy atoms and molecules\, on
the distances $ a \\ll Z^{-1/2}$ from one of the nuclei (with a charge $Z
_m$)\, we prove that the ground state electronic density $\\rho_\\Psi (x)$
is approximated in $L^p$-norm by the ground state electronic density for
a single atom in the model with no interactions between electrons.\n\nFurt
her\, on the distances $a \\gg Z^{-1}$ from all of the nuclei (with a char
ge $Z_1\,\\ldots\, Z_m$) we prove that $\\rho_\\Psi (x)$ is approximated i
n $L^p$-norm\, by the Thomas-Fermi density. We cover both non-relativistic
and relativistic cases.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Giuliani (University Roma Tre)
DTSTART:20200929T140000Z
DTEND:20200929T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/16
DESCRIPTION:Title: Non-renormalization of the `chiral anomaly' in interacting l
attice Weyl semimetals\nby Alessandro Giuliani (University Roma Tre) a
s part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWeyl
semimetals are 3D condensed matter systems characterized by a degenerate F
ermi surface\, consisting of a pair of `Weyl nodes'. Correspondingly\, in
the infrared limit\, these systems behave effectively as Weyl fermions in
3+1 dimensions. We consider a class of interacting 3D lattice models for W
eyl semimetals and prove that the quadratic response of the quasi-particle
flow between the Weyl nodes\, which is the condensed matter analogue of t
he chiral anomaly in QED4\, is universal\, that is\, independent of the in
teraction strength and form. Universality\, which is the counterpart of th
e Adler-Bardeen non-renormalization property of the chiral anomaly for the
infrared emergent description\, is proved to hold at a non-perturbative l
evel\, notwithstanding the presence of a lattice\n(in contrast with the or
iginal Adler-Bardeen theorem\, which is perturbative and requires relativi
stic invariance to hold). The proof relies on constructive bounds for the
Euclidean ground state correlations combined with lattice Ward Identities\
, and it is valid arbitrarily close to the critical point where the Weyl p
oints merge and the relativistic description breaks down. Joint work with
V. Mastropietro and M. Porta.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nalini Anantharaman (Strasbourg)
DTSTART:20201103T140000Z
DTEND:20201103T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/17
DESCRIPTION:Title: The bottom of the spectrum of a random hyperbolic surface\nby Nalini Anantharaman (Strasbourg) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nI will report on work in progress with
Laura Monk\, where we study the bottom of the spectrum of the laplacian\,
on a compact hyperbolic surface chosen at random\, in the limit of growing
genus. We pick combinatorial ideas from the study of random regular graph
s\, to propose a strategy to prove that\, with high probability\, there ar
e no eigenvalues below $1/4-\\epsilon$.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Peter Hintz (MIT)
DTSTART:20201110T140000Z
DTEND:20201110T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/18
DESCRIPTION:Title: Linear stability of slowly rotating Kerr spacetimes\nby
Peter Hintz (MIT) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nI will describe joint work with Dietrich Häfner and András
Vasy in which we study the asymptotic behavior of linearized gravitationa
l perturbations of Schwarzschild or slowly rotating Kerr black hole spacet
imes. We show that solutions of the linearized Einstein equation decay at
an inverse polynomial rate to a stationary solution (given by an infinites
imal variation of the mass and angular momentum of the black hole)\, plus
a pure gauge term. The proof uses a detailed description of the resolvent
of an associated wave equation on symmetric 2-tensors near zero energy.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Nachtergaele (UC Davis)
DTSTART:20201027T140000Z
DTEND:20201027T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/19
DESCRIPTION:Title: Gapped ground state phases of lattice systems - Stability of
the bulk gap\nby Bruno Nachtergaele (UC Davis) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nI will give an overview of
stability results for the spectral gap above the ground states of quantum
lattice systems obtained in the past decade and explain the overall strat
egy introduced by Bravyi\, Hastings\, and Michalakis. A new result I will
present proves the stability of the bulk gap for infinite systems with an
approach that bypasses possible gapless boundary modes (joint work with Bo
b Sims and Amanda Young).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yoshiko Ogata (University of Tokyo)
DTSTART:20201215T140000Z
DTEND:20201215T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/20
DESCRIPTION:Title: Classification of symmetry protected topological phases in q
uantum spin systems\nby Yoshiko Ogata (University of Tokyo) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nA Hamiltonian
is in a SPT phase with a given symmetry if it cannot be \nsmoothly deform
ed into a trivial Hamiltonian without a phase transition\, \nif the deform
ation preserves the symmetry\,\nwhile it can be smoothly deformed into a t
rivial Hamiltonian without a \nphase transition\, if the symmetry is broke
n during the deformation.\nWe consider this problem for one- and two-dimen
sional quantum spin systems with on-site finite \ngroup symmetries.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeremy Quastel (University of Toronto)
DTSTART:20201020T140000Z
DTEND:20201020T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/21
DESCRIPTION:Title: Towards KPZ Universality\nby Jeremy Quastel (University
of Toronto) as part of One world IAMP mathematical physics seminar\n\n\nAb
stract\nThe 1-d KPZ universality class contains random interface growth mo
dels\nas well as random polymer free energies and driven diffusive systems
. \nThe KPZ fixed point has now been determined\, through the exact solut
ion of a special model\nin the class\, TASEP\, and is expected to describe
the asymptotic fluctuations for all models in the class.\nIt is an integr
able Markov process\, with transition probabilities described by a system
of integrable PDE's.\n
\nVery recently\, new techniques have become ava
ilable to prove \nthe convergence of the KPZ equation itself\, as well as
some non-integrable extensions\nof TASEP\, to the KPZ fixed point. This t
alk will be a gentle introduction to these developments\nwith no prior kno
wledge assumed. The results are\, variously\, joint works with \nDaniel R
emenik\, Konstantin Matetski\, and Sourav Sarkar.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roland Bauerschmidt (University of Cambridge)
DTSTART:20201124T140000Z
DTEND:20201124T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/22
DESCRIPTION:Title: The Coleman correspondence at the free fermion point\nby
Roland Bauerschmidt (University of Cambridge) as part of One world IAMP m
athematical physics seminar\n\n\nAbstract\nTwo-dimensional statistical and
quantum field theories are\nspecial in many ways. One striking instance o
f this is the equivalence\nof certain bosonic and fermionic fields\, known
as bosonization. I will\nfirst review this correspondence in the explicit
instance of the\nmassless Gaussian free field and massless Euclidean Dira
c fermions. I\nwill then present a result that extends this correspondence
to the\nnon-Gaussian `massless' sine-Gordon field on $\\R^2$ at $\\beta=4
\\pi$ and\nmassive Dirac fermions. This is an instance of Coleman's predic
tion that\nthe `massless' sine-Gordon model and the massive Thirring model
are\nequivalent. We use this correspondence to show that correlations of
the\n`massless' sine-Gordon model decay exponentially for $\\beta=4\\pi$.\
nThis is joint work with C. Webb (arXiv:2010.07096).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Svitlana Mayboroda (University of Minnesota)
DTSTART:20201013T140000Z
DTEND:20201013T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/23
DESCRIPTION:Title: The landscape law for the integrated density of states\n
by Svitlana Mayboroda (University of Minnesota) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nComplexity of the geometry\, r
andomness of the potential\, and many other irregularities of the system c
an cause powerful\, albeit quite different\, manifestations of localizatio
n\, a phenomenon of sudden confinement of waves\, or eigenfunctions\, to a
small portion of the original domain. In the present talk we show that be
hind a possibly disordered system there exists a structure\, referred to a
s a landscape function\, which can predict the location and shape of the l
ocalized eigenfunctions\, a pattern of their exponential decay\, and deliv
er accurate bounds for the corresponding eigenvalues. In particular\, we e
stablish the "landscape law"\, the first non-asymptotic estimates from abo
ve and below on the integrated density of states of the Schroedinger opera
tor using a counting function for the minima of the localization landscape
. The results are deterministic\, and rely on a new uncertainty principle.
Narrowing down to the context of disordered potentials\, we derive the be
st currently available bounds on the integrated density of states for the
Anderson model.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Hollands (University of Leipzig)
DTSTART:20201117T140000Z
DTEND:20201117T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/24
DESCRIPTION:Title: (In)determinism Inside Black Holes\nby Stefan Hollands (
University of Leipzig) as part of One world IAMP mathematical physics semi
nar\n\n\nAbstract\nIn classical General Relativity\, the values of fields
on spacetime are\nuniquely determined by their initial values within its "
domain of\ndependence". However\, it may occur that the\nspacetime under c
onsideration extends beyond this domain\, and\nfields\, therefore\, are no
t entirely determined by their initial data. In fact\, such a naive\nfailu
re of determinism occurs inside all physically relevant black holes.\n\nTh
e boundary of the region determined by the initial data is\ncalled the "Ca
uchy horizon". Penrose has proposed ("strong cosmic censorship conjecture"
)\nthat the Cauchy horizon is actually unstable in the sense that the slig
htest perturbation caused\nby remnant fields convert it to a final singula
rity. Whether or not this is the case --\nand thus whether there is a real
problem with determinism -- has been put into question recently.\n\nIn th
is colloquium I ask wheter quantum effects will come to the rescue of stro
ng cosmic censorship.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ian Jauslin (Princeton University)
DTSTART:20200922T140000Z
DTEND:20200922T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/25
DESCRIPTION:Title: An effective equation to study Bose gasses at both low and h
igh densities\nby Ian Jauslin (Princeton University) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nI will discuss an eff
ective equation\, which is used to study the ground state\n of the interac
ting Bose gas. The interactions induce many-body correlations\n in the sys
tem\, which makes it very difficult to study\, be it analytically or\n num
erically. A very successful approach to solving this problem is Bogolubov\
n theory\, in which a series of approximations are made\, after which the\
n analysis reduces to a one-particle problem\, which incorporates the many
-body\n correlations. The effective equation I will discuss is arrived at
by making a\n very different set of approximations\, and\, like Bogolubov
theory\, ultimately\n reduces to a one-particle problem. But\, whereas Bog
olubov theory is accurate\n only for very small densities\, the effective
equation coincides with the\n many-body Bose gas at both low and at high d
ensities.\n\n I will show some\n theorems which make this statement more p
recise\, and present numerical\n evidence that this effective equation is
remarkably accurate for all\n densities\, small\, intermediate\, and large
. That is\, the analytical and\n numerical evidence suggest that this effe
ctive equation can capture many-body\n correlations in a one-particle pict
ure beyond what Bogolubov can accomplish.\n Thus\, this effective equation
gives an alternative approach to study the low\n density behavior of the
Bose gas (about which there still are many important\n open questions). In
addition\, it opens an avenue to understand the physics of\n the Bose gas
at intermediate densities\, which\, until now\, were only\n accessible to
Monte Carlo simulations.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Pizzo (University of Rome Tor Vergata)
DTSTART:20201201T140000Z
DTEND:20201201T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/26
DESCRIPTION:Title: Stability of gapped quantum chains under small perturbations
\nby Alessandro Pizzo (University of Rome Tor Vergata) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nWe consider a famil
y of quantum chains that has attracted much interest amongst people studyi
ng topological phases of matter. Their Hamiltonians are perturbations\, by
interactions of short range\, of a Hamiltonian consisting of on-site term
s and with a strictly positive energy gap above its ground-state energy. F
or interactions that are form-bounded w.r.t. the on-site Hamiltonian term
s\, we prove that the spectral gap of the perturbed Hamiltonian above its
ground-state energy is bounded from below by a positive constant uniforml
y in the length of the chain\, for small values of a coupling constant.\n\
nIn our proof we use a novel method based on local Lie-Schwinger conjugat
ions of the Hamiltonians associated with connected subsets of the chain\,
that can be also applied to complex Hamiltonians obtained by considering c
omplex values of the coupling constant.\n\nWe can treat fermions and boson
s on the same footing\, and our technique does not face a large field prob
lem\, even though bosons are involved\, in contrast to most approaches. Fu
rthermore the method can be extended to higher spatial dimensions.\n\n(Joi
nt work with S. Del Vecchio\, J. Fröhlich\, and S. Rossi.)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Katrin Wendland (Albert-Ludwigs-Universität Freiburg)
DTSTART:20201208T140000Z
DTEND:20201208T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/27
DESCRIPTION:Title: On invariants shared by geometry and conformal field theory<
/a>\nby Katrin Wendland (Albert-Ludwigs-Universität Freiburg) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nI will recall h
ow some conformal field theories can be given geometric interpretations. T
his can be useful from a practical point of view\, when geometric methods
are transferred from geometry to conformal field theory. I will in particu
lar focus on certain invariants that are shared by geometry and conformal
field theory\, including the complex elliptic genus. As we shall see\, thi
s invariant is also useful from a theoretical viewpoint\, since it capture
s information about generic properties of certain theories.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clotilde Fermanian-Kammerer (Université\; Paris Est - Cr&eac
ute\;teil Val de Marne)
DTSTART:20201006T140000Z
DTEND:20201006T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/28
DESCRIPTION:Title: Nonlinear quantum adiabatic approximation\nby Clotilde F
ermanian-Kammerer (Université\; Paris Est - Cré\;teil Val de M
arne) as part of One world IAMP mathematical physics seminar\n\n\nAbstract
\nWe will discuss generalization of the quantum adiabatic theorem to a non
linear setting. We will consider evolution equations where the Hamiltonian
operator depends on the time variable and on a finite number of parameter
s that are fixed on some coordinates of the unknown\, making the equation
non-linear. Under natural spectral hypotheses\, there exist special functi
ons that we call « Instantaneous nonlinear eigenvectors » such that\, in
the adiabatic limit\, the solutions of the nonlinear equations with those
initial data remain close to them\, up to a rapidly oscillating phase. We
will explain why this question arises\, discuss the proof of this result
and show how it can fail (works in collaboration with Alain Joye and Rémi
Carles).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabio Toninelli (Technical University Vienna)
DTSTART:20210112T140000Z
DTEND:20210112T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/29
DESCRIPTION:Title: The anisotropic KPZ equation and logarithmic super-diffusivi
ty\nby Fabio Toninelli (Technical University Vienna) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nThe AKPZ equation is
an anisotropic variant of the celebrated (two-dimensional) KPZ stochastic
PDE\, which is expected to describe the large-scale behavior of (2+1)-dime
nsional growth models whose average speed of growth is a non-convex funct
ion of the average slope (AKPZ universality class). Several interacting pa
rticle systems belonging to the AKPZ class are known\, notably a class of
two-dimensional interlaced particle systems introduced by A. Borodin and P
. Ferrari. In this talk\, I will show that the non-linearity of the AKPZ e
quation is marginally relevant in the Renormalization Group sense: in fact
\, while the 2d-SHE is invariant under diffusive rescaling\, for AKPZ the
diffusion coefficient diverges (logarithmically) for large times\, implyin
g marginal super-diffusivity. [Based on joint work with G. Cannizzaro and
D. Erhard]\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Seiringer (IST Austria)
DTSTART:20210119T140000Z
DTEND:20210119T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/30
DESCRIPTION:Title: Quantum fluctuations and dynamics of a strongly coupled pola
ron\nby Robert Seiringer (IST Austria) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nWe review old and new results on th
e Fröhlich polaron model. The discussion includes the validity of the (cl
assical) Landau--Pekar equations for the dynamics in the strong coupling l
imit\, quantum corrections to this limit\, as well as the divergence of th
e effective polaron mass.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Margherita Disertori (University of Bonn)
DTSTART:20210302T140000Z
DTEND:20210302T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/31
DESCRIPTION:Title: Supersymmetric transfer operators\nby Margherita Diserto
ri (University of Bonn) as part of One world IAMP mathematical physics sem
inar\n\n\nAbstract\nTransfer matrix approach is a powerful tool to study o
ne dimensional or quasi 1d statistical mechanical models. Transfer operato
r kernels arising in the context of quantum diffusion and the supersymme
tric approach display bosonic and fermionic components. For such kernels\,
the presence of fermion-boson symmetries allows to drastically simplify t
he problem. I will review the method and give some results for the case of
random band matrices.\n\nThis is joint work with Sasha Sodin and Martin L
ohmann.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Wehr (University of Arizona)
DTSTART:20210330T140000Z
DTEND:20210330T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/32
DESCRIPTION:Title: Aggregation and deaggregation of interacting micro swimmers<
/a>\nby Jan Wehr (University of Arizona) as part of One world IAMP mathema
tical physics seminar\n\n\nAbstract\nA swarm of light-sensitive robots is
moving in a planar region\, changing the direction of motion randomly. Ea
ch robot emits light\; in turn\, it adapts the speed of its motion to the
total intensity of the light shed on it by the other robots. The adaptati
on takes time---the sensorial delay. Using a natural approximation of the
equations of motion\, the robots may be programmed to make the sensorial
delay negative. In this case they are\, in some sense\, predicting the fu
ture. In a series of experiments by the Giovanni Volpe group and the Univ
ersity of Gothenburg (Sweden) it was shown that at a certain negative valu
e of the delay\, the collective behavior of the robots changes qualitative
ly from aggregation to deaggregation. I am going to explain this phenomen
on by an asymptotic analysis of the system of stochastic differential equa
tions\, describing the motion of a single robot in an inhomogeneous landsc
ape. \n\nThe results were obtained in a joint work with Giovanni Volpe\, M
ite Mijalkov and Austin McDaniel. They display an interesting feature: w
hile the original system is driven by a single noise source\, the limiting
one contains two independent ones. I will explain this by showing how on
e can generate two independent Wiener processes from a single one. Using
this fact to rigorously justify the asymptotic results is a work in progre
ss with Jeremiah Birrell.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jürg Fröhlich (ETH Zürich)
DTSTART:20210126T140000Z
DTEND:20210126T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/33
DESCRIPTION:Title: The Evolution of States as the Fourth Pillar of Quantum Mech
anics\nby Jürg Fröhlich (ETH Zürich) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nI present ideas about how to exten
d the standard formalism of Quantum\nMechanics in such a way that the theo
ry actually makes sense. My\ntentative extension is called\n\n
"ETH-Approach to Quantum Mechanics"\n\n(for "Events\, Trees and Histor
ies").\n\nThis approach supplies the last of four pillars QM can be constr
ucted upon\,\nwhich are:
\n(i) Physical quantities characteristic of
a physical system are represented\n by self-adjoint operators\;
\n
(ii) the time evolution of these operators is given by the Heisenberg equ
ation\;
\n(iii) meaningful notions of states and of "potential" and "ac
tual events" have\n to be introduced\; and
\n(iv) a general law fo
r the time evolution of states (superseding Schroedinger\n evolution\,
which is inadequate) must be formulated.\n\nBesides briefly sketching the
ETH-Approach in the setting of non-relativistic\nQM\, I present a family
of very simple models of a very heavy atom coupled to\nthe radiation field
in a limit where the speed of light tends to infinity\,\nAn analysis of t
hese models\, which illustrate the ETH Approach\, is the main\nsubject of
the talk.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tyler Helmuth (University of Durham)
DTSTART:20210223T140000Z
DTEND:20210223T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/34
DESCRIPTION:Title: Efficient algorithms for low-temperature spin systems\nb
y Tyler Helmuth (University of Durham) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nTwo fundamental algorithmic tasks assoc
iated to discrete statistical mechanics models are approximate counting an
d approximate sampling. At high temperatures Markov chains give efficient
algorithms\, but at low temperatures mixing times can become impractically
large\, and Markov chain methods may fail to be efficient. Recently\, exp
ansion methods (cluster expansions\, Pirogov--Sinai theory) have been put
to use to develop provably efficient low-temperature algorithms for some d
iscrete statistical mechanics models. I’ll introduce these algorithmic t
asks\, outline how expansion algorithms work\, and indicate some open dire
ctions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sylvia Serfaty (Courant Institute)
DTSTART:20210323T140000Z
DTEND:20210323T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/35
DESCRIPTION:Title: Ginzburg-Landau vortices\, old and new\nby Sylvia Serfat
y (Courant Institute) as part of One world IAMP mathematical physics semin
ar\n\n\nAbstract\nWe present a review of results on vortices in the 2D Gin
zburg-Landau model of superconductivity (also relevant for superfluidity a
nd Bose-Einstein condensates)\, their onset at critical fields\, interacti
on and patterns. We also report on recent joint work with Carlos Roman a
nd Etienne Sandier in which we study the onset of vortex lines in the 3D m
odel and derive an interaction energy for them.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Søren Fournais (Aarhus University)
DTSTART:20210105T140000Z
DTEND:20210105T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/36
DESCRIPTION:Title: The ground state energy of dilute Bose gases\nby Søren
Fournais (Aarhus University) as part of One world IAMP mathematical physic
s seminar\n\n\nAbstract\nThe rigorous calculation of the ground state ener
gy of dilute Bose gases has been a challenging problem since the 1950s. In
particular\, it is of interest to understand the extent to which the Bogo
liubov pairing theory correctly describes the ground state of this physica
l system.\nIn this talk I will report on a recent proof of the second term
in the energy expansion for dilute gases\, the so-called Lee-Huang-Yang t
erm\, and its relation to Bogoliubov theory.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Wu (NYU Shanghai)
DTSTART:20210202T140000Z
DTEND:20210202T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/37
DESCRIPTION:Title: Massless phases for the Villain model in $d \\geq 3$\nby
Wei Wu (NYU Shanghai) as part of One world IAMP mathematical physics semi
nar\n\n\nAbstract\nThe XY and the Villain models are mathematical idealiza
tion of real world models of liquid crystal\, liquid helium\, and supercon
ductors. Their phase transition has important applications in condensed ma
tter physics and led to the Nobel\nPrize in Physics in 2016. However we ar
e still far from a complete mathematical\nunderstanding of the transition.
The spin wave conjecture\, originally proposed by Dyson and by Mermin and
Wagner\, predicts that at low temperature\, large scale behaviors of thes
e models are closely related to Gaussian free fields. I will review the hi
storical background and discuss some recent progress on this conjecture in
$d \\geq 3$.\nBased on the joint work with Paul Dario (Tel Aviv).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gianluca Panati (University of Rome Sapienza)
DTSTART:20210316T140000Z
DTEND:20210316T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/38
DESCRIPTION:Title: The Localization Dichotomy in Solid State Physics\nby Gi
anluca Panati (University of Rome Sapienza) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nSolid state systems exhibit a subt
le intertwining between the topology of the\n"manifold" of occupied states
and the localization of electrons\, if the latter is appropriately define
d. \n
\nThis correspondence has been first noticed and proved\nin the c
ase of periodic gapped systems: for non interacting electrons\,\nlo
calization is measured via the localization of the Composite Wannier Bases
(CWBs)\nspanning the range of the Fermi projector $P_F$\, while the topol
ogical information is encoded \nin the (first) Chern class of the Fermi p
rojector. It has been proved\, for dimension $d \\leq 3$ \nthat only two r
egimes are possible:
\ni) either there exists an exponentially localiz
ed CWB\, and correspondingly the Chern \nclass of $P_F$ vanishes (ordinary
insulator)\;
\nii) or any possible choice of a CWB is delocali
zed\, in the sense that it \nyields an infinite expectation value for the
square of \nthe position operator\, and the Chern class is non zero (Chern
insulator).\n
\nMore recently\, the previous dichotomy has been reform
ulated in such a way that it applies\nalso to non-periodic systems\, and a
corresponding "Localization Dichotomy conjecture" for\nnon-periodic syste
ms has been stated. \n
\nIn my talk\, I will gently introduce the subje
ct\, starting from the periodic case\, and summarize the \nrecent attempts
\, by several groups\, to prove the Localization Dichotomy for non-periodi
c systems. \n
\nThe talk is based on work in collaboration with D. Mona
co\, M. Marcelli\, M. Moscolari\, \nA. Pisante\, and S. Teufel\, and on di
scussions with several colleagues.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gerald Dunne (University of Connecticut)
DTSTART:20210216T140000Z
DTEND:20210216T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/39
DESCRIPTION:Title: Resurgent Asymptotics and Non-perturbative Physics\nby G
erald Dunne (University of Connecticut) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nThere are several important conceptual
and computational questions concerning path integrals\, which have recent
ly been approached from new perspectives motivated by Ecalle's theory of r
esurgent functions\, a mathematical formalism that unifies perturbative an
d non-perturbative physics. I will review the basic ideas behind the conne
ctions between resurgent asymptotics and physics\, with examples from quan
tum mechanics and matrix models.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Herbert Spohn (TU Munich)
DTSTART:20210209T140000Z
DTEND:20210209T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/40
DESCRIPTION:Title: Generalised hydrodynamics of the Toda lattice\nby Herber
t Spohn (TU Munich) as part of One world IAMP mathematical physics seminar
\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Warzel (TU Munich)
DTSTART:20210309T140000Z
DTEND:20210309T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/41
DESCRIPTION:Title: An invitation to quantum spin glasses\nby Simone Warzel
(TU Munich) as part of One world IAMP mathematical physics seminar\n\n\nAb
stract\nQuantum spin glass models of mean-field type are prototypes of qua
ntum systems exhibiting phase transitions related to the spead of the eige
nstates in configuration space. \nOriginally motivated by spin glass phys
ics\, they are discussed in relation to many-body localisation phenomena\,
quantum adiabatic algorithms as well as in the context of models in mathe
matical biology. \nQuantum effects transform the rich phase diagram of cla
ssical spin glasses as described by Parisi’s theory into an even more co
lourful landscape of phases which range from purely quantum paramagnetic t
o intermediate behavior in which eigenstates occupy only a fraction of con
figuration space.\n\nIn this talk\, I will give an introduction to the mul
tifaceted motivations and challenges behind the study of these quantum gla
sses and explain existing and expected results.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech De Roeck (KU Leuven)
DTSTART:20210413T140000Z
DTEND:20210413T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/42
DESCRIPTION:Title: Impurities and boundaries for a class of gapped ground state
s\nby Wojciech De Roeck (KU Leuven) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nIn the last two decades\, a lot of rig
orous results have been proven for quantum ground states protected by a sp
ectral gap in their Hamiltonian. Think for example of decay of correlation
s\, the topological classification of states\, and area laws of entangleme
nt.\nFor all of those results\, the spectral gap is a necessary input\, bo
th on the conceptual and on the technical level. \nImagine now that we con
sider such a gapped Hamiltonian that is perturbed locally by a term that i
s not small\, such that we certainly cannot hope to preserve the global ga
p. Common sense dictates that\, far away from the perturbation\, the groun
d state should not be seriously affected by this perturbation. \nWhile we
cannot prove this in the generality in which it should be true\, I will de
scribe some results that go in this direction.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Carlen (Rutgers University)
DTSTART:20210420T140000Z
DTEND:20210420T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/43
DESCRIPTION:Title: Kac Master Equations\, Classical and Quantum\nby Eric Ca
rlen (Rutgers University) as part of One world IAMP mathematical physics s
eminar\n\n\nAbstract\nThis lecture will review recent progress and open pr
oblems concerning Kac Master Equations in both the classical and quantum s
etting. It will be based largely on recent papers written in collaboration
with Maria Carvalho\, Michael Loss and Bernt Wennberg.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bernard Helffer (Paris-Sud / Nantes)
DTSTART:20210406T140000Z
DTEND:20210406T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/44
DESCRIPTION:Title: Semiclassical methods and tunneling effects: old and new
\nby Bernard Helffer (Paris-Sud / Nantes) as part of One world IAMP mathem
atical physics seminar\n\n\nAbstract\nIn 1982-1983 the so-called symmetri
c double well problem was rigorously analyzed in any dimension in the semi
-classical context by B. Simon and Helffer-Sjöstrand.\nThis involves se
mi-classical Agmon estimates\, Harmonic approximation\, WKB constructions
and a very fine analysis of the so-called tunneling effect in order to est
ablish the splitting between the lowest eigenvalues.\n\nThe strategy follo
wed by Helffer-Sjöstrand appears to be quite efficient in many other con
texts. After recalling how it works on the initial double well problem\,\n
we will discuss in a rather impressionist way the main successes of the a
pproach along the years.\nFinally we will focus on a quite recent result b
y Bonnaillie-Hérau-Raymond devoted to the measure of a magnetic tunneling
in Surface Superconductivity and discuss open problems.\n\nThe presented
results correspond to contributions by various subsets of the following se
t of authors : Bonnaillie\, Fournais\, Helffer\, Hérau\, Kachmar\, Morame
\, Nier\,\nRaymond\, Simon\, Sjöstrand and many others...\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sabine Jansen (LMU Munich)
DTSTART:20210427T140000Z
DTEND:20210427T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/45
DESCRIPTION:Title: Virial expansion for mixtures: some examples & recent result
s\nby Sabine Jansen (LMU Munich) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nMayer's expansion is an expansion of the
pressure in powers of the activity (fugacity) in equilibrium statistical m
echanics\; the virial expansion is an expansion in powers of the density.
Rigorous convergence results have been available for decades\, nevertheles
s for mixtures the theory of density expansions is less advanced than the
theory of activity expansions. I will review the setting\, and discuss som
e recent results for the virial expansion for mixtures (multi-species syst
ems) and illustrate them with three concrete models: mixtures of hard sphe
res of different sizes\, non-overlapping rods of different lengths\, and a
hierarchical mixture of cubes in $Z^d$. The last two examples are helpful
toy models for which concrete formulas are available and phase transition
s can be studied. Based in part on joint works with Tobias Kuna\, Stephen
Tate\, Dimitrios Tsagkarogiannis and Daniel Ueltschi.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Brydges (University of British Columbia)
DTSTART:20210511T140000Z
DTEND:20210511T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/46
DESCRIPTION:Title: Lace expansions and spin models\nby David Brydges (Unive
rsity of British Columbia) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nI will review lace expansions starting with their\n
relation to the other expansions in statistical mechanics and then\ndiscus
sing their application to spin models. Akira Sakai opened\nthis avenue in
2007 with his proof that in sufficiently high dimension\n$d$ the two point
function for the critical Ising model is asymptotic\nto $c_d |x-y|^{-(d-2
)}$. In arxiv.org/abs/1905.096
05 Tyler\nHelmuth\, Mark Holmes and I have introduced a different way
to derive\nlace expansions based on the Symanzik random walk representatio
n.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcel Griesemer (University of Stuttgart)
DTSTART:20210518T140000Z
DTEND:20210518T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/47
DESCRIPTION:Title: From Short-Range to Contact Interactions in Many-Body Quantu
m Systems\nby Marcel Griesemer (University of Stuttgart) as part of On
e world IAMP mathematical physics seminar\n\n\nAbstract\nMany-body quantum
systems with short-ranged two-body interactions\, such as ultracold quant
um gases are often described by simplified models with contact interaction
s (sometimes called delta-potentials). The merit of such models is their s
implicity\, solvability (to some extent) and lack of irrelevant or unknown
detail. They are also toy models of renormalization. On the other hand\,
in dimensions $d\\geq 2$ contact interactions are not small perturbations
of the free energy\, which makes their self adjoint implementation in the
case of $N>2$ particles a subtle business. This talk gives an introduction
to the mathematics of many-particle quantum systems with two-body contact
interactions and their approximation by Schrödinger operators.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constanza Rojas-Molina (Cergy Paris University)
DTSTART:20210525T140000Z
DTEND:20210525T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/48
DESCRIPTION:Title: Fractional random Schrödinger operators\, integrated densit
y of states and localization\nby Constanza Rojas-Molina (Cergy Paris U
niversity) as part of One world IAMP mathematical physics seminar\n\n\nAbs
tract\nWe will review some recent results on the fractional Anderson model
\, a random Schrödinger operator driven by a fractional laplacian. The in
terest of the latter lies in its association to stable Levy processes\, ra
ndom walks with long jumps and anomalous diffusion. We discuss the interpl
ay between the non-locality of the fractional laplacian and the localizati
on properties of the random potential in the fractional Anderson model\, i
n both the continuous and discrete settings. In the discrete setting we st
udy the integrated density of states and show a fractional version of Lifs
hitz tails. This coincides with results obtained in the continuous setting
by the probability community. This talk is based on joint work with M. Ge
bert (LMU Munich).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Fewster (University of York)
DTSTART:20210504T140000Z
DTEND:20210504T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/49
DESCRIPTION:Title: Measurement of quantum fields in curved spacetimes\nby C
hris Fewster (University of York) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nA standard account of the measurement chain
in quantum mechanics involves a probe (itself a quantum system) coupled te
mporarily to the system of interest. Once the coupling is removed\, the pr
obe is measured and the results are interpreted as the measurement of a sy
stem observable. Measurement schemes of this type have been studied extens
ively in Quantum Measurement Theory\, but they are rarely discussed in the
context of quantum fields and still less on curved spacetimes. \n\nIn thi
s talk I will describe how measurement schemes may be formulated for quant
um fields on curved spacetime within the general setting of algebraic QFT.
In particular\, I will show how measurements of probe observables corresp
ond to measurements of "induced" local system observables and describe the
role of state update rules. The framework is local and fully covariant\,
allowing the consistent description of measurements made in spacelike sepa
rated regions. Furthermore\, specific models can be given in which the fra
mework may be exemplified by concrete calculations. I will also explain ho
w this framework can shed light on an old problem due to Sorkin concerning
"impossible measurements" in which measurement apparently conflicts with
causality. Finally\, I will discuss new results indicating that the system
observables that can be induced by measurement schemes form a large subsp
ace of the algebra of all local observables.\n\nThe talk is based on work
with Rainer Verch [Leipzig]\, (Comm. Math. Phys. 378\, 851–889(2020)\, a
rXiv:1810.06512\; see also arXiv:1904.06944 for a summary)\, with Henning
Bostelmann and Maximilian Ruep [York] ( Phys. Rev. D 103 (2021) 025017\; a
rXiv:2003.04660) and work in progress with Ian Jubb [Dublin] and Maximilia
n Ruep.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Schlein (University of Zürich)
DTSTART:20210601T140000Z
DTEND:20210601T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/50
DESCRIPTION:Title: Correlation energy of weakly interacting Fermi gases\nby
Benjamin Schlein (University of Zürich) as part of One world IAMP mathem
atical physics seminar\n\n\nAbstract\nWe consider Fermi gases in a mean-fi
eld regime. To leading order\, the ground state energy is given by Hartree
-Fock theory. The correction to the Hartree-Fock energy\, produced by the
many-body interaction\, is known as correlation energy. In this talk\, we
obtain a formula for the correlation energy\, based on the observation tha
t\, energetically\, the main excitations of the Fermi sea are particle-hol
e pairs that behave\, approximately\, as bosons and can therefore be dealt
with through (bosonic) Bogoliubov theory. The talk is based on joint work
s with N. Benedikter\, P.T. Nam\, M. Porta and R. Seiringer.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laszlo Erdös (IST Austria)
DTSTART:20210608T140000Z
DTEND:20210608T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/51
DESCRIPTION:Title: Eigenstate thermalisation hypothesis and Gaussian fluctuatio
ns for Wigner matrices\nby Laszlo Erdös (IST Austria) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nWe prove that any
deterministic matrix is approximately\nthe identity in the eigenbasis of a
large random Wigner matrix W\nwith an optimal error inversely proportiona
l to the square root of the dimension.\nThis verifies a strong form of Qu
antum Unique Ergodicity \nwith an optimal convergence rate and we also pro
ve Gaussian fluctuations\naround this convergence.\nThe key technical tool
is a new multi-resolvent local law for Wigner\nensemble and the Dyson Bro
wnian motion for eigenvector overlaps.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gordon Slade (UBC Vancouver)
DTSTART:20210615T140000Z
DTEND:20210615T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/52
DESCRIPTION:Title: Mean-field tricritical polymers\nby Gordon Slade (UBC Va
ncouver) as part of One world IAMP mathematical physics seminar\n\n\nAbstr
act\nWe provide a full description of a tricritical phase diagram in the s
etting of a mean-field random walk model of a polymer density transition.
The model involves a continuous-time random walk on the complete graph in
the limit as the number of vertices N in the graph grows to infinity. The
walk has a repulsive self-interaction\, as well as a competing attractive
self-interaction whose strength is controlled by a parameter g. A chemical
potential ν controls the walk length. We determine the phase diagram in
the (g\,ν) plane\, as a model of a density transition for a single linear
polymer chain. The proof uses a supersymmetric representation for the ran
dom walk model\, followed by a single block-spin renormalisation group ste
p to reduce the problem to a 1-dimensional integral\, followed by applicat
ion of the Laplace method for an integral with a large parameter. The talk
is based on joint work with Roland Bauerschmidt\, Probability and Mathema
tical Physics 1\, 167-204 (2020)\; arXiv:1911.00395 .\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clément Tauber (University of Strasbourg)
DTSTART:20210622T140000Z
DTEND:20210622T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/53
DESCRIPTION:Title: Topological indices for shallow-water waves\nby Clément
Tauber (University of Strasbourg) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nIn this talk\, I will apply tools from topo
logical insulators to a fluid dynamics problem: the rotating shallow-water
wave model with odd viscosity. The bulk-edge correspondence explains the
presence of remarkably stable waves propagating towards the east along the
equator and observed in some Earth oceanic layers. The odd viscous term i
s a small-scale regularization that provides a well defined Chern number f
or this continuous model where momentum space is unbounded. Equatorial wav
es then appear as interface modes between two hemispheres with a different
topology. However\, in presence of a sharp boundary there is a surprising
mismatch in the bulk-edge correspondence: the number of edge modes depend
s on the boundary condition. I will explain the origin of such a mismatch
using scattering theory and Levinson’s theorem. This talk is based on a
series of joint works with Pierre Delplace\, Antoine Venaille\, Gian Miche
le Graf and Hansueli Jud.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mathieu Lewin (Paris Dauphine University)
DTSTART:20210629T140000Z
DTEND:20210629T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/54
DESCRIPTION:Title: Density Functional Theory: some recent results\nby Mathi
eu Lewin (Paris Dauphine University) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nThe quantum electrons in an atom or a mol
ecule are in principle described by the Schrödinger multi-particle linear
equation. Unfortunately\, in most cases it is essentially impossible to f
ind a sufficiently precise numerical approximation of the solution\, due t
o the very high dimensionality of the problem. It is absolutely necessary
to resort to approximate models\, most of which being nonlinear. Density F
unctional Theory (DFT) is probably the most successful and widely used met
hod in Chemistry and Physics. In this talk I will explain what DFT is and
outline its mathematical formulation. I will then describe some recent res
ults obtained in collaboration with Elliott H. Lieb (Princeton) and Robert
Seiringer (IST Austria).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikolaos Zygouras (University of Warwick)
DTSTART:20210706T140000Z
DTEND:20210706T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/55
DESCRIPTION:Title: On the 2d-KPZ\nby Nikolaos Zygouras (University of Warwi
ck) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\n
The Kardar-Parisi-Zhang (KPZ) equation in dimension 1 is by now fairly wel
l understood\, both in terms of its solution theory and its phenomenology.
But in the critical dimension 2\, the first steps of progress have only
recently been made\, which shows signs of a rich structure. In particular\
, a phase transition is observed when the noise is suitably scaled. Below
the critical scaling\, the 2d KPZ coincides with the Edwards-Wilkinson uni
versality\, while at the critical scaling and beyond\, its behaviour is st
ill mysterious. We will review joint works with F. Caravenna and R. Sun as
well as contributions by other groups\, and expose some of the tools used
\, including (discrete) stochastic analysis\, renewal theory\, and mathema
tical physics ideas from the study of disorder relevance and Schrodinger o
perators with point interactions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Malamud (Peoples Friendship University of Russia\, Moscow)
DTSTART:20210713T140000Z
DTEND:20210713T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/56
DESCRIPTION:Title: On the spectral theory of Schrodinger and Dirac operators wi
th point interactions and quantum graphs\nby Mark Malamud (Peoples Fri
endship University of Russia\, Moscow) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nModern concepts of extension theory of
symmetric operators\, including concepts of boundary triples\, correspondi
ng Weyl functions\, and boundary operators will be discussed. Applications
to Schrodinger and Dirac operators with point interactions\, as well as t
o quantum graphs\, will be demonstrated. It turns out that certain spectra
l properties of each of these operators (deficiency indices\, selfadjointn
ess\, discreteness\, lower semiboundedness\, etc) strictly correlate to th
at of a special difference operator. In the first two cases the correspond
ing difference operator is generated by a special Jacobi matrix. This matr
ix appears as a boundary operator of the corresponding Schrodinger and Dir
ac realization in an appropriate boundary triple. In the case of quantum g
raphs a similar role is played by a certain weighted discrete Laplacian on
the underlying discrete graph\, which also appears as a boundary operator
.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Phan Thành Nam (LMU Munich)
DTSTART:20210720T140000Z
DTEND:20210720T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/57
DESCRIPTION:Title: Bogoliubov excitation spectrum of dilute trapped Bose gases<
/a>\nby Phan Thành Nam (LMU Munich) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nIn 1947\, Bogoliubov proposed an approxim
ation for the low-lying eigenvalues of weakly interacting Bose gases and u
sed that to explain Landau’s criterion for superfluidity. We will discus
s a rigorous derivation of Bogoliubov’s approximation for a general trap
ped Bose gas in the Gross-Pitaevskii regime\, where the two-body scatterin
g process of particles leads to an interesting nonlinear effect. The talk
is based on joint work with Arnaud Triay.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eveliina Peltola (University of Bonn)
DTSTART:20210727T140000Z
DTEND:20210727T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/58
DESCRIPTION:Title: On large deviations of SLEs\, real rational functions\, and
zeta-regularized determinants of Laplacians\nby Eveliina Peltola (Univ
ersity of Bonn) as part of One world IAMP mathematical physics seminar\n\n
\nAbstract\nWhen studying large deviations (LDP) of Schramm-Loewner evolut
ion (SLE) curves\,\nwe recently introduced a ''Loewner potential'' that de
scribes the rate function for the LDP.\nThis object turned out to have sev
eral intrinsic\, and perhaps surprising\, connections to various fields.\n
For instance\, it has a simple expression in terms of zeta-regularized det
erminants of Laplace-Beltrami operators.\nOn the other hand\, minima of th
e Loewner potential solve a nonlinear first order PDE that arises\nin a se
miclassical limit of certain correlation functions in conformal field theo
ry\,\narguably also related to isomonodromic systems.\nFinally\, and perha
ps most interestingly\, the Loewner potential minimizers classify\nrationa
l functions with real critical points\, thereby providing a novel proof fo
r\na version of the now well-known Shapiro-Shapiro conjecture in real enum
erative geometry.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antti Knowles (University of Geneva)
DTSTART:20210831T140000Z
DTEND:20210831T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/59
DESCRIPTION:Title: The Euclidean phi^4_2 theory as a limit of an interacting Bo
se gas\nby Antti Knowles (University of Geneva) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nLocal Euclidean field theo
ries over d-dimensional space have been extensively studied in the mathema
tical literature since the sixties\, motivated by high-energy physics and
statistical mechanics. For d=2\, I explain how the complex scalar field th
eory with quartic interaction arises as a limit of an interacting Bose gas
at positive temperature\, when the density of the gas becomes large and t
he range of the interaction becomes small. The proof is based on a quantit
ative analysis of a new functional integral representation of the interact
ing Bose gas combined with a Nelson-type argument for a general nonlocal f
ield theory. Joint work with Jürg Fröhlich\, Benjamin Schlein\, and Vedr
an Sohinger.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Germain (New York University)
DTSTART:20210907T140000Z
DTEND:20210907T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/60
DESCRIPTION:Title: Derivation of the kinetic wave equation\nby Pierre Germa
in (New York University) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nThe kinetic wave equation (KWE) is to nonlinear waves
what the Boltzmann equation is to classical particles. The KWE is also ve
ry closely related to quantum versions of the Boltzmann equation. Finally\
, the KWE provides an entrypoint into turbulent phenomena\, since it is ai
med at describing weakly turbulent flows. For all these reasons\, the KWE
is an interesting object\, and the question of its validity a fundamental
one. I will review recent progress on this question.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniela Cadamuro (University of Leipzig)
DTSTART:20210810T140000Z
DTEND:20210810T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/61
DESCRIPTION:Title: Operator-algebraic construction of quantum integrable models
with bound states\nby Daniela Cadamuro (University of Leipzig) as par
t of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe rigoro
us construction of quantum field theories with self-interaction is one of
the longstanding problems of Mathematical Physics. Progress in this respec
t has been made in integrable field theories in 1+1 spacetime dimensions.
These are characterized by a factorizing scattering matrix\, where two-par
ticle interaction determines scattering completely.\n\nSpecifically\, some
of these theories (so-called scalar models without bound states) have bee
n successfully treated in the operator-algebraic approach\, which is based
on quantum fields localized in infinitely extended wedge regions. The exi
stence of strictly localized observables is then obtained by abstract W*-a
lgebraic arguments. This avoids dealing with the functional analytic prope
rties of pointlike interacting fields\, which are difficult to control due
to the convergence problem of the infinite series of their form factors.\
n\nIn extension of these results\, we consider S-matrices with poles in th
e physical strip (corresponding to the notion of `bound states’ in the
quantum mechanical sense). We exhibit wedge-local fields in these models\,
which arise as a deformation of those in the non-boundstate models by an
additive term\, the so called ``bound state operator''. This technique app
lies to a variety of theories\, e.g.\, the Bullough-Dodd model\, the Z(N)-
Ising model\, the affine Toda field theories and the Sine-Gordon model. Th
e link between these wedge-local fields and strictly local operator algebr
as is subject to ongoing research.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ron Peled (Tel Aviv University)
DTSTART:20210824T140000Z
DTEND:20210824T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/62
DESCRIPTION:Title: Quantitative estimates for the effect of disorder on low-dim
ensional lattice systems\nby Ron Peled (Tel Aviv University) as part o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nThe addition
of an arbitrarily weak random field to low-dimensional classical statistic
al physics models leads to the "rounding" of first-order phase transitions
at all temperatures\, as predicted in 1975 by Imry and Ma and proved rigo
rously in 1989 by Aizenman and Wehr. This phenomenon was recently quantifi
ed for the two-dimensional random-field Ising model (RFIM)\, proving that
it exhibits exponential decay of correlations at all temperatures and all
positive random-field strengths. The talk will present new results on the
quantitative aspects of the phenomenon for general systems with discrete a
nd continuous symmetries\, including Potts\, spin $O(n)$ and spin glass mo
dels. The discussion is further extended to real- and integer-valued heigh
t function models driven by a random field\, for which we study the fluctu
ations of the gradient and height variables. Among the challenges presente
d by the latter setup is a conjectured roughening transition in the random
-field strength for the three-dimensional integer-valued random-field Gaus
sian free field.\nJoint work with Paul Dario and Matan Harel.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sasha Sodin (Queen Mary University London)
DTSTART:20210817T140000Z
DTEND:20210817T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/63
DESCRIPTION:Title: Lower bounds on the eigenfunctions of random Schroedinger op
erators in a strip\nby Sasha Sodin (Queen Mary University London) as p
art of One world IAMP mathematical physics seminar\n\n\nAbstract\nIt is kn
own that the eigenfunctions of a random Schroedinger\noperator in a strip
decay exponentially. In some regimes\, the same is\ntrue in higher dimensi
ons. It is however not clear whether the\neigenfunctions have an exact rat
e of exponential decay. In the strip\,\nit is natural to expect that the r
ate should be given by the slowest\nLyapunov exponent\, however\, only the
upper bound has been previously\nestablished.\n\nWe shall discuss some re
cent progress on this problem\, and its\nconnection to a question\, perhap
s interesting in its own right\, in the\ntheory of random matrix products.
Based on joint work with Ilya\nGoldsheid.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yvan Velenik (Université\; de Genè\;ve)
DTSTART:20210914T140000Z
DTEND:20210914T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/64
DESCRIPTION:Title: Fluctuations of a layer of unstable phase in the planar Isin
g model\nby Yvan Velenik (Université\; de Genè\;ve) as par
t of One world IAMP mathematical physics seminar\n\n\nAbstract\nI'll first
review some of the known results about phase separation\, fluctuations of
interfaces and (equilibrium) aspects of metastability in the planar Ising
model. This will naturally lead us to consider a setup in which an interf
ace separates a layer of unstable phase along the boundary of the system f
rom the stable phase occupying the bulk. I'll then describe a recent work\
, in which we prove that\, after a 1/3:2/3 scaling\, the distribution of t
his interface weakly converges to the distribution of the stationary traje
ctories of an explicit Ferrari-Spohn diffusion. The proof relies on a rigo
rous reduction to an effective interface model\, which I'll briefly sketch
.\n\nThis is based on a joint work with Dima Ioffe\, Sébastien Ott and Se
nya Shlosman\; arXiv:2011.11997 .\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rostyslav Hryniv (Ukrainian Catholic University)
DTSTART:20210928T140000Z
DTEND:20210928T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/65
DESCRIPTION:Title: Generalized soliton solutions of the Korteweg-de Vries equat
ion\nby Rostyslav Hryniv (Ukrainian Catholic University) as part of On
e world IAMP mathematical physics seminar\n\n\nAbstract\nThe Korteweg--de
Vries (KdV) equation is a non-linear dispersive equation describing shallo
w-water waves and possessing many intriguing properties. One of them is ex
istence of the so-called soliton solutions representing solitary waves tra
velling with constant speed and shape\, as well as a special way in which
several such solitons interact. Another interesting fact is that solutions
of the KdV equation can be obtained as solutions of the inverse scatterin
g problem for the family of associated Schroedinger operators\, as discove
red by S.Gardner\, J.Green\, M.Kruskal and R.Miura in 1967\, and the class
ical soliton solutions of the KdV correspond precisely to the so-called re
flectionless potentials (I.Kay and H.Moses\, 1956).\n\nThe aim of this tal
k is two-fold. Firstly\, we characterise the family of all Schroedinger op
erators with integrable reflectionless potentials and give an explicit for
mula producing all such potentials. Secondly\, we use the inverse scatteri
ng transform approach to describe all solutions of the KdV equation whose
initial (t=0) profile is an integrable reflectionless potential. Such solu
tions will stay integrable and reflectionless for all positive times and c
an be called generalized soliton solutions of KdV. \n\nThis research exte
nds and specifies in several ways the previous work on reflectionless pote
ntials by V.Marchenko\, C.Remling et al. and generalized soliton solutions
of the KdV equation introduced by V.Marchenko in 1991 and F.Gesztesy\, W.
Karwowski\, and Z.Zhao in 1992. The talk is based on a joint project with
B.Melnyk and Ya.Mykytyuk (Lviv Franko National University).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Loss (Georgia Institute of Technology)
DTSTART:20211005T140000Z
DTEND:20211005T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/66
DESCRIPTION:Title: Which magnetic fields support a zero mode?\nby Michael L
oss (Georgia Institute of Technology) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nI present some results concerning the si
ze of magnetic fields that support zero modes for the three dimensional Di
rac equation and related problems for spinor equations. The critical quant
ity\, is the $3/2$ norm of the magnetic field $B$. The point is that the s
pinor structure enters the analysis in a crucial way. This is joint work w
ith Rupert Frank at LMU Munich.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/66/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rupert L. Frank (California Institute of Technology and LMU Munich
)
DTSTART:20211019T140000Z
DTEND:20211019T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/67
DESCRIPTION:Title: Eigenvalue bounds for Schrodinger operators with complex pot
entials\nby Rupert L. Frank (California Institute of Technology and LM
U Munich) as part of One world IAMP mathematical physics seminar\n\n\nAbst
ract\nWe discuss open problems and recent progress concerning eigenvalues
of Schrodinger operators with complex potentials. We seek bounds for indiv
idual eigenvalues or sums of them which depend on the potential only throu
gh some L^p norm. While the analogues of these questions are (almost) comp
letely understood for real potentials\, the complex case leads to complete
ly new phenomena\, which are related to interesting questions in harmonic
and complex analysis.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Klaus Fredenhagen (Universität Hamburg)
DTSTART:20210921T140000Z
DTEND:20210921T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/68
DESCRIPTION:Title: Towards an algebraic construction of Quantum Field Theory\nby Klaus Fredenhagen (Universität Hamburg) as part of One world IAMP m
athematical physics seminar\n\n\nAbstract\nAlgebraic quantum field theory
provides a conceptual and mathematically precise framework for the analysi
s of structural features of quantum field theory.\nDuring the last decades
\, it has in addition provided a generalization of quantum field theory to
generic Lorentzian spacetimes\, and\, moreover\, an elegant reformulation
of renormalized perturbative quantum field theory. The principles used th
ere actually determine also a C*-algebraic formulation which is surprising
ly rich and leads to some nonperturbative results.\nIn particular\, the ti
me slice axiom can be derived\, a version of Noether's theorem is obtained
\, and the renormalization group flow caused by anomalies becomes visible
in the algebraic structure. The talk is based on joint work with Detlev Bu
chholz (2020) and on joint work with Romeo Brunetti\, Michael Dütsch and
Kasia Rejzner (2021).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Nurowski (Polish Academy of Sciences\, Warsaw)
DTSTART:20211116T140000Z
DTEND:20211116T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/69
DESCRIPTION:Title: Split real form of Lie group G2: simple\, exceptional and na
turally appearing in physics\nby Paweł Nurowski (Polish Academy of Sc
iences\, Warsaw) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nA simple exceptional Lie group G2 was predicted to exist by W
ilhelm Killing in 1887. Its geometric realization appeared later\, in 1893
\; it is due to Friedrich Engel and Elie Cartan. They realized this group
as a symmetry group of two quite different geometric structures on five ma
nifolds. \nIn my talk I will try to explain how the idea of these G2 symme
tric geometric structures could came to minds of Cartan and Engel. My expl
anation will be based on properties of the root diagram of G2. I will keep
my lecture self contained\, so I will define the G2 root diagram and will
explain how to use it. After nailing down the two 5-dimensional G2 -symme
tric geometries of Cartan and Engel\, I will show how they appear naturall
y in constrained classical mechanics.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christophe Garban (Université Lyon 1)
DTSTART:20211012T140000Z
DTEND:20211012T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/70
DESCRIPTION:Title: Continuous symmetry breaking along the Nishimori line\nb
y Christophe Garban (Université Lyon 1) as part of One world IAMP mathema
tical physics seminar\n\n\nAbstract\nI will discuss a new way to prove con
tinuous symmetry breaking for (classical) spin systems on Z^d\, d\\geq 3 w
hich does not rely on "reflection positivity". \nOur method applies to mo
dels whose spins take values in S^1\, SU(n) or SO(n) in the presence of a
certain quenched disorder called the Nishimori line. The proof of continuo
us symmetry breaking is based on two ingredients
\n1) the notion of "g
roup synchronization" in Bayesian statistics. In particular a recent resul
t by Abbe\, Massoulié\, Montanari\, Sly and Srivastava (2018) which prove
s group synchronization when d\\geq 3.
\n2) a gauge transformation on
both the disorder and the spin configurations due to Nishimori (1981).
\nI will end the talk with an application of these techniques to a deconf
ining transition for U(1) lattice gauge theory on the Nishimori line. \nTh
is is a joint work with Tom Spencer (https://arxiv.org/abs/2109.01617).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomaž Prosen (University of Ljubljana)
DTSTART:20211026T140000Z
DTEND:20211026T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/71
DESCRIPTION:Title: Random Matrix Spectral Fluctuations in Quantum Lattice Syste
ms\nby Tomaž Prosen (University of Ljubljana) as part of One world IA
MP mathematical physics seminar\n\n\nAbstract\nI will discuss the problem
of unreasonable effectiveness of random matrix theory for description of s
pectral fluctuations in extended quantum lattice systems. A class of inter
acting spin systems has been recently identified - specifically\, the so-c
alled dual unitary circuits - where the spectral form factor is proven to
match with circular ensembles of random matrix theory. The key ideas of no
vel methodology needed in the proofs will be discussed which are very diff
erent than the standard periodic-orbit based methods in quantum chaos of f
ew body semiclassical systems.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lea Bossmann (IST Austria)
DTSTART:20211102T140000Z
DTEND:20211102T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/72
DESCRIPTION:Title: Asymptotic expansion of low-energy excitations for weakly in
teracting bosons\nby Lea Bossmann (IST Austria) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nWe consider a system of N
bosons in the mean-field scaling regime in an external trapping potential.
We derive an asymptotic expansion of the low-energy eigenstates and the c
orresponding energies\, which provides corrections to Bogoliubov theory to
any order in 1/N. We show that the structure of the ground state and of t
he non-degenerate low-energy eigenstates is preserved by the dynamics if t
he external trap is switched off. This talk is based on joint works with S
ören Petrat\, Peter Pickl\, Robert Seiringer and Avy Soffer.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gaultier Lambert (University of Zurich)
DTSTART:20211109T140000Z
DTEND:20211109T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/73
DESCRIPTION:Title: Universality for free fermions point processes\nby Gault
ier Lambert (University of Zurich) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nI report on recent results obtained with A.
Deleporte on universality of local statistics for the ground state of a f
ree Fermi gas confined in a generic potential on ℝ^n. This model was int
roduced by Macchi in 1975 and it forms a determinantal point process whose
kernel is the spectral projector associated to a Schrödinger operator
−ℏ^2Δ+V. I will explain how to obtain the asymptotics of the kernel o
f this projector as ℏ→0 using methods from semiclassical analysis and
discuss some probabilistic consequences. In particular\, this implies univ
ersality of microscopic fluctuations\, both in the bulk and around regular
boundary points.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julian Sonner (University of Geneva)
DTSTART:20211123T140000Z
DTEND:20211123T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/74
DESCRIPTION:Title: Random matrices and black holes: new connections from hologr
aphic duality\nby Julian Sonner (University of Geneva) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nQuantum chaotic sys
tems are often defined via the assertion that their spectral statistics co
incides with\, or is well approximated by\, random matrix theory (RMT). In
turn\, the late-time ergodic behaviour of chaotic quantum systems is expe
cted to fall into a small number of universality classes of RMT dynamics.
Recent developments in holographic duality have made it possible to charac
terise the ergodic late-time behaviour of black holes in asymptotically an
ti de Sitter space in similar terms. In this talk I will start by introduc
ing the basic ideas and notions of holographic duality (also known as AdS/
CFT)\, before moving on to these more recent developments\, mostly focussi
ng on low-dimensional examples.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Niklas Beisert (ETH Zurich)
DTSTART:20211130T140000Z
DTEND:20211130T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/75
DESCRIPTION:Title: Planar Integrability and Yangian Symmetry in N=4 Supersymmet
ric Yang–Mills\nby Niklas Beisert (ETH Zurich) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nThe discovery and utilisa
tion of integrability in the planar limit of certain gauge and string theo
ry models has made available many exciting non-perturbative results and in
sights for the AdS/CFT correspondence. In this talk I will introduce the p
rototypical AdS/CFT duality between string theory on AdS₅×S⁵ and N=4
supersymmetric Yang–Mills theory\, and highlight the usefulness of plana
r integrability through some achievements. I will then present a formal no
tion of integrability as a hidden Yangian symmetry of the action. Importan
tly\, this symmetry is realised on field theory objects in a non-standard
fashion for which a rigorous framework to deal with its implications is la
cking. I will demonstrate that this symmetry indeed leads to non-trivial r
elations for quantum correlations functions of this model. In order to mak
e them work out\, I also show in what sense the symmetry is compatible wit
h BRST gauge fixing.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nina Holden (ETH Zurich)
DTSTART:20211207T140000Z
DTEND:20211207T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/76
DESCRIPTION:Title: Conformal welding in Liouville quantum gravity: recent resul
ts and applications\nby Nina Holden (ETH Zurich) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nLiouville quantum gravity
(LQG) is a natural model for a random fractal surface with origins in con
formal field theory and string theory. A powerful tool in the study of LQG
is conformal welding\, where multiple LQG surfaces are combined into a si
ngle LQG surface. The interfaces between the original LQG surfaces are typ
ically described by variants of the random fractal curves known as Schramm
-Loewner evolutions (SLE). We will present a few recent conformal welding
results for LQG surfaces and applications to the integrability of SLE and
LQG partition functions. Based on joint work with Ang and Sun and with Leh
mkuehler.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolai Reshetikhin (University of California\, Berkeley)
DTSTART:20211214T140000Z
DTEND:20211214T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/77
DESCRIPTION:Title: On the asymptotic behavior of character measures in large te
nsor powers of finite dimensional representations of simple Lie algebras\nby Nicolai Reshetikhin (University of California\, Berkeley) as part o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nLet $V$ be a
finite dimensional representation of a simple Lie algebra and $H$ be an po
sitive element of its Cartan subalgebra ("magnetic field"). On the space $
V^{\\otimes N}$ we have a natural density matrix $N\\exp(-H)$ where $H$ ac
ts diagonally: $H(x\\otimes y\\otimes z\\dots)=Hx\\otimes y\\otimes z\\dot
s+x\\otimes Hy\\otimes z\\dots+x\\otimes y\\otimes Hz\\dots+\\dots$. The s
pace $V^{\\otimes N}$ decomposes into a direct\nsum of irreducible subrepr
esentations:\n\\[\nV^{\\otimes N}\\simeq \\oplus_{\\lambda} V_\\lambda^{\\
oplus m(\\lambda\, N)}\n\\]\nwhere $\\lambda$ is the highest weight of the
representation $V_\\lambda$ and $m(\\lambda\, N)$\nis its multiplicity in
the tensor product. The character distribution assigns the probability \n
\\[\np_{\\lambda}(N\,H)=\\frac{m(\\lambda\, N)Tr_{V_\\lambda}(e^{-H)})}{(T
r_V(e^{-H}))^N}\n\\]\nto each $\\lambda$ in the decomposition of the tenso
r product.\n\nOne of the natural problems for this distribution is to find
its asymptotic \nin the limit $N\\to \\infty$ and $\\lambda\\to \\infty$
in the appropriate way.\nWhen $H=0$ the character distribution becomes a u
niform distribution.\nIn this case\, in such generality the asymptotic wa
s studied by Ph. Biane\, 1993 by T. Tate and S. Zelditch\, 2004. For tenso
r powers of vector representations the asymptotic was derived by S. Kerov
in 1986. When $H$ is generic\, i.e. when $H$ is strictly inside of the pri
ncipal Weyl chamber\nit was computed by O.Postnova and N.R. in 2018. This
talk is based on a joint work with O. Postnova and V. Serganova (to appear
on the arxiv).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudio Dappiaggi (Università\; di Pavia)
DTSTART:20220111T140000Z
DTEND:20220111T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/78
DESCRIPTION:Title: Stochastic Partial Differential Equations and Renormalizatio
n à la Epstein-Glaser\nby Claudio Dappiaggi (Università\; di Pa
via) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\
nWe present a novel framework for the study of a large class of nonlinear
stochastic partial differential equations\, which is inspired by the algeb
raic approach to quantum\nfield theory. The main merit is that\, by realiz
ing random fields within a suitable algebra of functional-valued distribut
ions\, we are able to use specific techniques proper of microlocal\nanalys
is. These allow us to deal with renormalization using an Epstein-Glaser pe
rspective\, hence without resorting to any specific regularization scheme.
As a concrete example we shall use this method to discuss the stochastic
$\\Phi^3_d$ model and we shall comment on its applicability to the stocha
stic nonlinear Schrödinger equation -- Joint work with Nicolò Drago\, Pa
olo Rinaldi and Lorenzo Zambotti.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcin Lis (University of Vienna)
DTSTART:20220118T140000Z
DTEND:20220118T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/79
DESCRIPTION:Title: An elementary proof of phase transition in the planar XY mod
el\nby Marcin Lis (University of Vienna) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nUsing elementary methods we obtai
n a power-law lower bound on the two-point function of the planar XY spin
model at low temperatures. This was famously first rigorously obtained by
Fröhlich and Spencer and establishes a Berezinskii-Kosterlitz-Thouless ph
ase transition in the model. Our argument relies on a new loop representat
ion of spin correlations\, a recent result of Lammers on delocalisation of
integer-valued height functions\, and classical correlation inequalities.
This is joint work with Diederik van Engelenburg.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Schweigert (Universität Hamburg)
DTSTART:20211221T140000Z
DTEND:20211221T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/80
DESCRIPTION:Title: More about CFT correlators\nby Christoph Schweigert (Uni
versität Hamburg) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nI will explain two recent developments concerning bulk fiel
ds in\ntwo-dimensional rational conformal field theories: the importance o
f\nthe relative Serre functor to study bulk fields for logarithmic\nconfor
mal field theories and the use of stringnet techniques to\nsimplify the co
nstruction of correlators for semisimple modular\ntensor categories.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vojkan Jaksic (McGill University)
DTSTART:20220322T140000Z
DTEND:20220322T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/81
DESCRIPTION:Title: Approach to equilibrium in translation-invariant quantum sys
tems: some structural results\nby Vojkan Jaksic (McGill University) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe for
mulate the problem of approach to equilibrium in algebraic quantum statist
ical mechanics and study some of its structural aspects\, focusing on the
relation between the zeroth law of thermodynamics (approach to equilibrium
) and the second law (increase of entropy). Our main result is that approa
ch to equilibrium is necessarily accompanied by a strict increase of the s
pecific (mean) entropy. In the course of our analysis\, we introduce the c
oncept of quantum weak Gibbs state which is of independent interest.\n\nTh
is is a joint work with C. Tauber and C.-A. Pillet\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Schiavina (ETH Zürich)
DTSTART:20220125T140000Z
DTEND:20220125T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/83
DESCRIPTION:Title: Ruelle Zeta Function from Field Theory\nby Michele Schia
vina (ETH Zürich) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nI will discuss a field-theoretic interpretation of Ruelle's
zeta function\, which "counts" prime geodesics on hyperbolic manifolds\,
as the partition function for a topological field theory (BF) with an unus
ual gauge fixing condition available on contact manifolds. This suggests a
rephrasing of a conjecture due to Fried\, on the equivalence between Ruel
le's zeta function (at zero) and the analytic torsion\, as gauge-fixing in
dependence in the Batalin--Vilkovisky formalism.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daisuke Shiraishi (Kyoto University)
DTSTART:20220201T140000Z
DTEND:20220201T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/84
DESCRIPTION:Title: Recent progress on loop-erased random walk in three dimensio
ns\nby Daisuke Shiraishi (Kyoto University) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nLoop-erased random walk (LERW)
is a model for a random simple path\, which is created by running a simpl
e random walk and\, whenever the random walk hits its path\, removing the
resulting loop and continuing. LERW was originally introduced by Greg Lawl
er in 1980. Since then\, it has been studied extensively both in mathemati
cs and physics literature. Indeed\,\nLERW has a strong connection with oth
er models in statistical physics\, especially the uniform spanning tree wh
ich arises in statistical physics in conjunction with the Potts model. In
this talk\, I will talk about some recent progress on LERW while focusing
on the three-dimensional case. This is joint work with Xinyi Li.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Makiko Sasada (University of Tokyo)
DTSTART:20220308T140000Z
DTEND:20220308T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/85
DESCRIPTION:Title: Topological structures and the role of symmetry in the hydro
dynamic limit of nongradient models\nby Makiko Sasada (University of T
okyo) as part of One world IAMP mathematical physics seminar\n\n\nAbstract
\nRecently\, we introduce a general framework in order to systematically i
nvestigate hydrodynamics limits of various microscopic stochastic large sc
ale interacting systems in a unified fashion. In particular\, we introduce
d a new cohomology theory called the uniformly cohomology to investigate t
he underlying topological structure of the interacting system. Our theory
gives a new interpretation of the macroscopic parameters\, the role played
by the group action on the microscopic system\, and the origin of the dif
fusion matrix associated to the macroscopic hydrodynamic equation. Further
more\, we rigorously formulate and prove for a relatively general class of
models Varadhan’s decomposition of closed forms\, which plays a key rol
e in the proof of hydrodynamic limits of nongradient models. Our result is
applicable for many important models including generalized exclusion proc
esses\, multi-species exclusion processes\, exclusion processes on crystal
lattices and so on. Based on joint papers with Kenichi Bannai and Yukio K
ametani \n(https://arxiv.org/abs/2009.04699\, https://arxiv.org/abs/21
11.08934).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/85/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Serena Cenatiempo (GSSI L'Aquila)
DTSTART:20220329T140000Z
DTEND:20220329T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/86
DESCRIPTION:Title: Trial states for the zero temperature dilute Bose gas\nb
y Serena Cenatiempo (GSSI L'Aquila) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nNon-relativistic interacting bosons at zer
o temperature\, in two and three dimensions\, are expected to exhibit a fa
scinating critical phase\, famously known as condensate phase. Even though
a proof of Bose-Einstein condensation in the thermodynamic limit is still
beyond reach of the current available methods\, the mathematical physics
community has recently gained an enhanced comprehension of other aspects o
f the macroscopic behavior of low temperature Bose gases\, in several inte
resting regimes. In this talk we review part of these advances\, by descri
bing trial states for the dilute three dimensional Bose gas\, capturing th
e celebrated Lee-Huang-Yang sub-leading correction to the ground state ene
rgy. We conclude with some open questions and perspectives.\n\nBased on jo
int works with G. Basti\, C. Boccato\, C. Brennecke\, C. Caraci\, A. Olgia
ti\, G. Pasqualetti and B. Schlein.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jerzy Lewandowski (University of Warsaw)
DTSTART:20220315T140000Z
DTEND:20220315T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/87
DESCRIPTION:Title: Horizon equations\nby Jerzy Lewandowski (University of W
arsaw) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\nThe extremity assumptions imposes a set of non-trivial equations on the
\nintrinsic and extrinsic geometry of the horizon. Some of them already\ng
ot more attention since they are applied in the near horizon geometries\n(
NHG)\, some other are less know. All of them are very important for the\ne
xistence and uniqueness of extremal black hole solutions to Einstein's\neq
uations. In 4d spacetime\, an integrability condition for the NHG\nequatio
n is available that is satisfied by the family of non-extremal\nhorizon ge
ometries\, namely by those that are of the Petrov type D. What\nis special
about that equation\, is that its solutions exhibit similar\nproperties t
o those proved in the global black hole spacetime theory:\nspherical topol
ogy of horizon cross sections\, rigidity\, no-hair.\n\nExtension of the re
search to the horizons that had a Hopf bundle\nstructure led to interestin
g results about the global structure of the\nKerr-NUT-(A)dS spaces. Misne
r's construction was generalised to the\ncase when none of the three para
meters (NUT\, Kerr\, and the cosmological\nconstant) vanishes. The resulti
ng family contains also exact solutions\nto Einstein's equations that admi
t no horizon or nowhere time like\nKilling vector and describe a topologic
ally spherical universe evolving\nfrom the past scry to the future scry i
n a non-singular manner.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martin Zirnbauer (University of Cologne)
DTSTART:20220215T140000Z
DTEND:20220215T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/88
DESCRIPTION:Title: Field theory of Anderson transitions reviewed: Color-Flavor
Transformation\nby Martin Zirnbauer (University of Cologne) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nThis talk is i
n two parts. First\, the field-theoretic approach to (de-)localization in
Anderson-type models for disordered electrons is reviewed\, with emphasis
placed on the presence of a hyperbolic target-space sector and the expecte
d pattern of spontaneous symmetry breaking. The second part is a review of
the "Color-Flavor (CF) Transformation" (MZ\, 1996). Conceived as a varian
t of the Efetov-Wegner supersymmetry method\, the CF Transformation is tai
lored to quantum systems with disorder distributed according to Haar measu
re for any compact Lie group of classical type (A\, B\, C\, or D). It has
been applied to Dyson's Circular Ensembles\, random-link network models\,
quantum chaotic graphs\, disordered Floquet dynamics\, and more. It is rev
iewed here as a rigorous tool to derive the effective field theory for sys
tems in the metallic regime.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Skibsted (Aarhus University)
DTSTART:20220208T140000Z
DTEND:20220208T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/89
DESCRIPTION:Title: Stationary scattering theory\, the N-body long-range case\nby Erik Skibsted (Aarhus University) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nWithin the class of Dereziński-Enss p
air-potentials which includes Coulomb potentials and for which asymptotic
completeness is known\, we show that all entries of the N-body quantum sca
ttering matrix have a well-defined meaning at any given non-threshold ener
gy. As a function of the energy parameter the scattering matrix is weakly
continuous. This result generalizes a similar one obtained previously by Y
afaev for systems of particles interacting by short-range potentials. As f
or Yafaev’s works we do not make any assumption on the decay of channel
eigenstates. The main part of the proof consists in establishing a number
of Kato-smoothness bounds needed for justifying a new formula for the scat
tering matrix. Similarly we construct and show strong continuity of channe
l wave matrices for all non-threshold energies. The set of so-called stati
onary complete energies has full measure. We show that the scattering and
channel wave matrices constitute a well-defined ‘scattering theory’ at
such energies\, in particular at any stationary complete energy the scatt
ering matrix is unitary\, strongly continuous and characterized by asympto
tics of minimum generalized eigenfunctions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marek Biskup (UCLA)
DTSTART:20220301T140000Z
DTEND:20220301T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/90
DESCRIPTION:Title: Extremal points of random walks on planar and tree graphs\nby Marek Biskup (UCLA) as part of One world IAMP mathematical physics s
eminar\n\n\nAbstract\nI will review recent progress on the description of
points heavily visited by paths of random walks. The focus will be on the
situations where the random walk has an approximate scale-invariant struct
ure and the associated local time process is thus logarithmically correlat
ed in space. Two geometric settings will be considered: the simple random
walk on finite subsets of the square lattice and the random walk on homoge
neous trees of finite depth. In the former case\, a full description will
be given of the scaling limit of thick\, thin and avoided points for the w
alk run up to the times proportional to the cover time. For the latter set
ting\, the law of the most frequently visited leaf-vertex\, and the time s
pent there\, will be given in the limit of the tree depth tending to infin
ity. In both cases\, the spatial laws will be determined by a correspondin
g multiplicative chaos measure. Based on joint papers with Y. Abe\, S. Lee
and O. Louidor.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenzo Taggi (Sapienza Università di Roma)
DTSTART:20220222T140000Z
DTEND:20220222T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/91
DESCRIPTION:Title: Macroscopic loops in the interacting Bose gas\, Spin O(N) an
d related models\nby Lorenzo Taggi (Sapienza Università di Roma) as p
art of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe consi
der a general system of interacting random loops which includes several mo
dels of interest\, such as the spin O(N) model\, the double dimer model\,
random lattice permutations\, and is related to the loop O(N) model and to
the interacting Bose gas in discrete space. We present an overview on the
se models\, introduce some of the main open questions about the size and t
he geometry of the loops\, and present some recent results about the occur
rence of macroscopic loops in dimensions d > 2 as the inverse temperature
is large enough.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edward Witten (IAS)
DTSTART:20220412T140000Z
DTEND:20220412T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/92
DESCRIPTION:Title: Black Hole Entropies and Algebras\nby Edward Witten (IAS
) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nI
will review the idea of black hole entropy\, as originally discovered by B
ekenstein and Hawking roughly half a century ago\, and then explain how to
interpret black hole entropy in terms of an appropriate algebra of observ
ables.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/92/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Deepak Dhar (IISER Pune)
DTSTART:20220426T140000Z
DTEND:20220426T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/93
DESCRIPTION:Title: Hard rigid rods on hypercubical lattices\nby Deepak Dhar
(IISER Pune) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nI consider a system of hard rigid rods of length $k$ and width
$1$\, on $d$-dimensional hypercubic lattices. \nI will show that in the l
imit of large $k$\, the entropy per site at full packing $ s(d\,k)$ for $
d=2$ satisfies \n$$ \\lim_{k \\rightarrow \\infty} \\frac { s(d\,k) k^2
}{\\log k} =1\, $$\nand give heuristic arguments that this result would
be true also for all dimensions $d>2.$\n\nIf $k$ is large enough ($ k> 6
$ in $2$-d\, and $k>4$ in $3$-d)\, this model is known to undergo two ph
ase transitions when chemical potential is increased: from a low density i
sotropic phase to an intermediate density nematic phase\, and on further
increase to a high-density phase with no orientational order. I will pre
sent evidence to suport the conjecture that\, for large $k$\, the second
phase transition is a first order transition with a discontinuity in densi
ty as a function of the chemical potential\, in all dimensions greater th
an 1\, and if the chemical potential per rod at the transition is $\\mu^*(
k\,d)$\, and the density of holes jumps from a value $\\epsilon_1(k\,d)$
to $\\epsilon_2(k\,d)$\, we have for all $d \\geq 2$\n$$\\lim_{ k \\right
arrow \\infty} \\frac{ \\epsilon_1(d\, k) k^2}{\\log k} =1\,$$\n$$\\lim_{k
\\rightarrow \\infty} \\frac{ \\exp\\left[ \\frac{\\mu^*(d\, k)}{k} \\rig
ht] \\log k}{k} =1\,$$\n$$\\lim_{k \\rightarrow \\infty} \\frac{\\epsilo
n_2(d\,k) k ^m}{\\epsilon_1(d\,k)} =0\, ~{\\rm for~ all}~m>0.$$\n\nReferen
ces: Deepak Dhar and R. Rajesh\, Phys. Rev. E 103\, 042130 (2021)\;\n Aag
am Shah\, D. Dhar and R. Rajesh\, Phys. Rev. E. 105\, 034103 (2022).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech Dybalski (Adam Mickiewicz University)
DTSTART:20220517T140000Z
DTEND:20220517T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/94
DESCRIPTION:Title: Interacting massless excitations in 1+1 dimensional QFT\
nby Wojciech Dybalski (Adam Mickiewicz University) as part of One world IA
MP mathematical physics seminar\n\n\nAbstract\nMassless 1+1 dimensional qu
antum field theories have a peculiar\nscattering theory. Since the motion
of the excitations is dispersionless\, \nonly the distinction between left
-movers and right-movers is meaningful. \nThus complete particle interpret
ation (asymptotic completeness) can be expected already at the level of tw
o-body scattering. This effect will be illustrated by certain wedge-local
models of interacting Wigner particles. In the second part of the talk I w
ill move to the more exotic case of infraparticles\, i.e.\, excitations wh
ich are not of Wigner type. It is known that infraparticles abound in 1+1
massless QFT\, even in the familiar case of free field theory. A natural d
efinition of a scattering amplitude for infraparticles will be proposed an
d tested in this latter model. Paradoxically\, infraparticles in free fiel
d theory exhibit non-trivial scattering. \n\nThe talk is based on joint wo
rks with Yoh Tanimoto (CMP 305\, 427-440 (2011)) and Jens Mund (arXiv:2109
.02128).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vieri Mastropietro (University of Milan)
DTSTART:20220510T140000Z
DTEND:20220510T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/95
DESCRIPTION:Title: Anomalies and non-perturbative QFT\nby Vieri Mastropietr
o (University of Milan) as part of One world IAMP mathematical physics sem
inar\n\n\nAbstract\nAdler and Bardeen in 1969 established the non-renormal
ization of the chiral anomaly\, writing it as a perturbative expansion whi
ch is order by order vanishing\; since then\, this property has found unco
untable applications\, including the Standard Model consistence via the an
omaly cancellation condition (Bouchiat\, Iliopoulos\, Meyer 1972). After
reviewing briefly this notion\, we prove the anomaly non renormalization a
t a non-perturbative level in the case of lattice vector boson-fermion mod
els in d=1+1 (uniformly in the lattice) and in d=3+1 (up to a cut-off of t
he order of the inverse coupling). The proof relies on bounds on the large
distance decay of correlations and Ward Identities\, both exact and emerg
ing. In the case of chiral models\, like the effective electroweak theory
with quartic Fermi interaction in d=3+1\, some Ward Identites are violated
and the anomaly can be proved to vanish up to subdominant corrections whi
ch are rigorously bounded\, under the cancellation condition on charges an
d with a cut-off of the order of the inverse coupling. Open problems and c
onjectures will be finally discussed.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Saffirio (University of Basel)
DTSTART:20220621T140000Z
DTEND:20220621T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/96
DESCRIPTION:Title: Mean-field evolution and semiclassical limit of many interac
ting fermions\nby Chiara Saffirio (University of Basel) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nWe will review rec
ent progresses in the derivation of effective evolution equations for the
dynamics of many weakly interacting fermions. We will focus on the mean-fi
eld regime and couple it with a semiclassical limit to obtain\, as the num
ber of particles goes to infinity\, the Hartree-Fock and the Vlasov equati
ons. We will comment on the class of singular interactions and quantum sta
tes that we are able to treat\, drawing a comparison with the PDE theory o
f the limiting equations.\nBased on joint works with J. Chong and L. Lafl
èche.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Doyon (King's College London)
DTSTART:20220531T140000Z
DTEND:20220531T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/98
DESCRIPTION:Title: Ergodicity\, large-scale correlations and hydrodynamics in m
any-body systems\nby Benjamin Doyon (King's College London) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nLong-time beha
viours in statistical ensembles of many-body systems are notoriously diffi
cult to access. Hydrodynamics\, which is the theory for the emergent large
-scale dynamics\, gives a lot of information\, such as exact asymptotics o
f correlation functions. It turns out that at the Euler scale\, the emerge
nt theory for extended systems is largely universal. I will discuss a numb
er of such universal results in one dimension of space. Some can be shown
rigorously: a notion of ergodicity at all frequencies hold for correlation
functions in stationary states of all short-range quantum spin chains. Th
e Boltzmann-Gibbs principle\, where local observables project onto hydrody
namic modes in two-point functions\, and the linearised Euler equations\,
are also established. The complete space of hydrodynamic modes is the spac
e of ``extensive conserved quantities”\, which is defined unambiguously.
I will illustrate these concepts in integrable systems\, using generalise
d hydrodynamics. For correlations in non-stationary states\, much less is
established. I will describe a macroscopic fluctuation theory for the Eule
r scale which provides a framework for these. In particular\, I will expla
in how a new type of long-range correlations\, hitherto not observed\, app
ear when the system is subject to fluid motion\, which breaks the paradigm
that separate fluid cells are not correlated.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Owen Gwilliam (University of Massachusetts Amherst)
DTSTART:20220628T140000Z
DTEND:20220628T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/99
DESCRIPTION:Title: Observables in the Batalin-Vilkovisky formalism: from Feynma
n diagrams to commutative diagrams\nby Owen Gwilliam (University of Ma
ssachusetts Amherst) as part of One world IAMP mathematical physics semina
r\n\n\nAbstract\nThis talk will discuss a convergence between perturbative
QFT and higher algebra\, in the sense of homological algebra\, operads\,
and higher categories\, although we do not expect the listener to have any
expertise in those topics. A key notion here is a factorization algebra\,
which captures the local-to-global nature of the observables of a field t
heory and which is due to Beilinson and Drinfeld. With a focus on the exam
ple of Chern-Simons theory\, we will discuss how the BV/factorization pack
age offers a new view on the emergence of algebraic structures\, like brai
ded monoidal categories\, from physics.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/99/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Correggi (Politecnico di Milano)
DTSTART:20220705T140000Z
DTEND:20220705T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/100
DESCRIPTION:Title: Ground State Properties in the Quasi-Classical Regime\n
by Michele Correggi (Politecnico di Milano) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nWe study the ground state energy a
nd ground states of systems coupling non-relativistic quantum particles an
d force-carrying Bose fields\, such as radiation\, in the quasi-classical
approximation. The latter is very useful whenever the force-carrying field
has a very large number of excitations\, and thus behaves in a semiclassi
cal way\, while the non-relativistic particles\, on the other hand\, retai
n their microscopic features. We prove that the ground state energy of the
fully microscopic model converges to the one of a nonlinear quasi classic
al functional depending on both the particles' wave function and the class
ical configuration of the field. Equivalently\, this energy can be interpr
eted as the lowest energy of a Pekar-like functional with an effective non
linear interaction for the particles only. If the particles are confined\,
the ground state of the microscopic system converges as well\, to a proba
bility measure concentrated on the set of minimizers of the quasi classica
l energy.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello (Perimeter Institute)
DTSTART:20220524T140000Z
DTEND:20220524T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/101
DESCRIPTION:Title: Form factors of gauge theory as correlators of a vertex alg
ebra\nby Kevin Costello (Perimeter Institute) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nForm factors are scattering
amplitudes in the presence of a local operator. I will explain that\, for
certain gauge groups\, form factors of self-dual Yang-Mills theory (with s
ome additional fields) are the correlators of a vertex algebra. This is jo
int work with Natalie Paquette\, and is closely related to the celestial h
olography program.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hirosi Ooguri (Caltech & Kavli IPMU)
DTSTART:20220419T140000Z
DTEND:20220419T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/102
DESCRIPTION:Title: Symmetry in QFT and Gravity\nby Hirosi Ooguri (Caltech
& Kavli IPMU) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nI will review aspects of symmetry in quantum field theory and co
mbine them with the AdS/CFT correspondence to derive constraints on symmet
ry in quantum gravity. The quantum gravity constraints to be discussed inc
lude the no-go theorem on global symmetry\, the completeness of gauge char
ges\, and the decomposition of high energy states into gauge group represe
ntations.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jacob Shapiro (Princeton)
DTSTART:20220405T140000Z
DTEND:20220405T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/103
DESCRIPTION:Title: Continuum and strongly disordered topological insulators\nby Jacob Shapiro (Princeton) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nA natural question to ask in the field of topo
logical insulators is whether continuum descriptions on L^2(R^d) and effec
tive discrete descriptions on l^2(Z^d) agree\, at the level of the long ti
me dynamics and at the level of the topological indices. This is shown to
be the case at least for a class of models of the integer quantum Hall eff
ect. The basic tool to approach the problem is homotopies of Fredholm oper
ators. This same tool is also shown to apply to other problems in topologi
cal insulators\, such as the bulk-edge correspondence for Z_2 time-reversa
l invariant strongly disordered discrete systems. This talk is based on jo
int works with Michael I. Weinstein and with Jeff Schenker and Alex Bols.\
n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Teufel (University of Tübingen)
DTSTART:20220712T140000Z
DTEND:20220712T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/104
DESCRIPTION:Title: A slightly different look at the bulk-edge correspondence i
n quantum Hall systems\nby Stefan Teufel (University of Tübingen) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe bul
k-edge correspondence of transport coefficients in quantum Hall systems is
usually shown for systems with a (mobility) gap in the bulk and at zero t
emperature. I will present recent results showing equality of magnetizatio
n in the bulk and edge current in microscopic models without and with inte
raction between electrons. This equality holds at positive temperature and
without assuming a (mobility) gap in the bulk\, and is robust to perturba
tions near the edges. I then discuss how the equality of transport coeffic
ients can be recovered from this form of bulk-edge correspondence\, at lea
st in some cases. My talk is based on joint work with Horia Cornean\, Jona
s Lampart\, Massimo Moscolari\, and Tom Wessel.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Ueltschi (University of Warwick)
DTSTART:20220503T140000Z
DTEND:20220503T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/105
DESCRIPTION:Title: Random loop models and their universal behaviour in dimensi
on 3+\nby Daniel Ueltschi (University of Warwick) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nI will discuss several l
oop soup models that represent classical or quantum systems\nof statistica
l physics. These systems undergo phase transitions that are characterised\
nby the occurrence of macroscopic loops. \n\nAs it turns out\, the joint d
istribution of the loop lengths exhibits a universal behaviour:\nIn 3+ dim
ension it is always given by a Poisson-Dirichlet distribution. The heurist
ics\nis based on the fact that the loops are so intertwined that they beha
ve effectively in\nmean-field fashion. Hence the connection to the split-m
erge process\, whose invariant\nmeasure is Poisson-Dirichlet.\n\nI will al
so discuss consequences about symmetry breaking in certain quantum spin\ns
ystems.\n\nThis talk is based on collaborations over the years with D. Gan
dolfo\, J. Ruiz\, C. Goldschmidt\,\nP. Windridge\, V. Betz\, S. Grosskinsk
y\, A. Lovisolo\, C. Benassi\, J. Bjö\;rnberg\,\nJ. Frö\;hlich.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Aizenman (Princeton)
DTSTART:20220607T140000Z
DTEND:20220607T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/106
DESCRIPTION:Title: A new perspective on a pair of two dimensional phenomena: d
elocalization in random height functions and the Berezinskii-Kosterlitz-Th
ouless phase of O(2) symmetric spin models\nby Michael Aizenman (Princ
eton) as part of One world IAMP mathematical physics seminar\n\n\nAbstract
\nDelocalization in integer-restricted Gaussian field\, and other random h
eight functions formulated over planar doubly-periodic lattices\, is shown
to imply slow (power law) decay of correlations in the corresponding dual
O(2) symmetric two-component spin model. The link proceeds through a lowe
r bound on the spin-spin correlation in terms of the probability of their
sites being on a common level loop of the dual random height function. Mo
tivated by this observation\, we have extended the recent proof by P. Lamm
ers of delocalization transition in two dimensional graphs of degree three
\, to all doubly periodic graphs\, in particular to Z^2. The extension is
established through a monotonicity argument based on lattice inequalities
of O. Regev and N. Stephens-Davidowitz. Taken together the results yield
a new perspective on the BKT phase transition in O(2)-invariant models and
complete a new proof of delocalization in two-dimensional integer-valued
height functions. (Both phenomena are unique to two dimension\, and have b
een previously proven and studied by other means). \nThat talk is based o
n a joint work by M. Aizenman\, M. Harel J. Shapiro and R. Peled.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Camillo De Lellis (IAS)
DTSTART:20221129T140000Z
DTEND:20221129T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/107
DESCRIPTION:Title: Anomalous dissipation for the forced Navier-Stokes equation
s\nby Camillo De Lellis (IAS) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nConsider smooth (or at least Leray) solution
s to 3d Navier-Stokes\n\\[\n\\left\\{\n\\begin{array}{ll}\n\\partial_t u^\
\varepsilon + {\\rm div}\\\, (u^\\varepsilon \\otimes u^\\varepsilon ) + \
\nabla p^\\varepsilon = \\varepsilon \\Delta u^\\varepsilon\\\\ \\\\\nu^\\
varepsilon (0\, \\cdot) = u^\\varepsilon_0\\\, .\n\\end{array}\\right.\n\\
]\nWhile the balance of the energy is\n\\[\n\\frac{d}{dt} \\frac{1}{2} \\i
nt |u|^2 (x\,t)\\\, dx = - \\varepsilon \\int |Du|^2 (x\,t)\\\, dx\\\, \,\
n\\]\nit is a tenet of the theory of fully developed turbulence that in a
variety of situations the left hand side should typically be independent o
f $\\varepsilon$: the mechanism is not supposed to be ignited by high osci
llations in the initial data\, which would trigger an ``immediate'' dissip
ation through the viscosity\, but it is rather thought to be an effect of
the quadratic nonlinearity. It is on the other hand very challenging to pr
oduce rigorous examples. If the bounds on $u_0^\\varepsilon$ are too stron
g\, the well-posedness theory for Euler obstructs the anomalous dissipatio
n up until the first blow-up time of Euler. With sufficiently coarse bound
s Euler can be shown to have a variety of dissipative solutions\, but it i
s very difficult to prove the convergence of Navier-Stokes to any of them.
\nIn a recent joint work with Elia Bruè we study the forced version of
the equation and we can prove rigorously that\, as soon as the regularity
of the force drops below the known thresholds for the well-posedness of cl
assical Euler\, it is in fact possible to show anomalous dissipation.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karol Kozlowski (ENS Lyon)
DTSTART:20221018T140000Z
DTEND:20221018T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/109
DESCRIPTION:Title: Towards an exact rigorous construction of the Sinh-Gordon q
uantum field theory in 1+1 dimensions\nby Karol Kozlowski (ENS Lyon) a
s part of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe b
ootstrap program was devised in the late 70s/early 80s as a possible path
for a fully explicit construction of numerous massive integrable quantum f
ield theories in 1+1 dimensions. Ultimately\, it allows one to express the
physically pertinent observables in these models --- the multi-point corr
elation functions also called Wightman functions --- in terms of form fact
or series expansion. On technical grounds\, the latter correspond to fully
explicit series of multiple integrals in which the $n^{\\rm th}$ summand
is given by a $n$-fold integral. The well definiteness of such a construct
ion amounts to proving the convergence of these series expansions and this
was a basically an open problem.\n\nIn this talk\, I will review the boos
trap approach to the construction of the Sinh-Gordon quantum field theory.
In particular\, I will discuss the type of representations one gets for t
he multi-point correlation functions in this model. Then\, I will discuss
the recent progress I achieved on the convergence problem for the form fac
tor series arising in the description of space-like separated two-point fu
nctions. The proof of the convergence of amounts to obtaining a sufficient
ly sharp estimate on the leading large-$n$ behaviour of the $n$-fold integ
ral arising in those series. This appeared possible by refining some of th
e techniques that were fruitful in the analysis of the large-$n$ behaviour
of integrals over the spectrum of $n\\times n$ random Hermitian matrices.
\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/109/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dorothea Bahns (Georg-August-Universität Göttingen)
DTSTART:20220927T140000Z
DTEND:20220927T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/110
DESCRIPTION:Title: The Sine Gordon Model in hyperbolic signature\nby Dorot
hea Bahns (Georg-August-Universität Göttingen) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nI will review some recent res
ults in the construction of the Sine Gordon\nmodel in hyperbolic signature
in the setting of perturbative algebraic\nquantum field theory. One focus
is on the construction of a Haag Kastler\nnet of observables (of operator
s on a Hilbert space)\, the other will be\nto explain how the adiabatic sw
itching function can be removed in\nexpectation values in thermal states.
The methods presented are a\nmixture of "old and new" in constructive and
algebraic quantum field theory.\n\nThis is joint work with Kasia Rejzner\,
Klaus Fredenhagen\, and Nicola\nPinamonti.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Slava Rychkov (IHES)
DTSTART:20220920T140000Z
DTEND:20220920T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/111
DESCRIPTION:Title: Tensor Renormalization Group at Low Temperatures\nby Sl
ava Rychkov (IHES) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nTensor RG is a real-space approach to renormalization in la
ttice models. It shows impressive numerical results\, but its rigorous the
ory is still in its infancy. I will start by reminding the basics of Tenso
r RG\, and what makes it potentially more powerful than Wilson-Kadanoff ap
proach. I will then explain how Tensor RG can be used to understand the Is
ing model in nonzero magnetic field at low temperatures. This gives an alt
ernative to the Pirogov-Sinai theory and to the renormalization group meth
ods in the contour representation from the 1980’s. Joint work with Tom K
ennedy\, to appear soon.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomohiro Sasamoto (Tokyo Institute of Technology)
DTSTART:20220719T140000Z
DTEND:20220719T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/112
DESCRIPTION:Title: Mapping macroscopic fluctuation theory for the symmetric si
mple exclusion process to a classically integrable system\nby Tomohiro
Sasamoto (Tokyo Institute of Technology) as part of One world IAMP mathem
atical physics seminar\n\n\nAbstract\nThe large deviation principle for sy
mmetric simple exclusion process(SEP) had been established by \nKipnis\, O
lla\, Varadhan in 1989 [1]. A somewhat different formulation\, known as th
e macroscopic \nfluctuation theory (MFT)\, was initiated and developed by
Jona-Lasinio et al in 2000’s [2]. The basic \nequations of the theory\,
MFT equations\, are coupled nonlinear partial differential equations and \
nhave resisted exact analysis except for stationary situation. In this tal
k we introduce a novel \ngeneralization of the Cole-Hopf transformation an
d show that it maps the MFT equations for SEP \nto the classically integra
ble Ablowitz-Kaup-Newell-Segur(AKNS) system. This allows us to solve \nthe
equations exactly in time dependent regime by adapting standard ideas of
inverse scattering method. \n\nThe talk is based on a joint work with Kiro
ne Mallick and Hiroki Moriya [3]. \n\nReferences\n\n[1] C. Kipnis\, S. Oll
a\, S. R. S. Varadhan\, \nHydrodynamics and large deviations for simple ex
clusion processes\, Comm. Pure Appl. Math.\, 42:115–137\, 1989.\n\n[2] L
. Bertini\, A. De Sole\, D. Gabrielli\, G. Jona-Lasinio\, and C. Landim\,\
nMacroscopic fluctuation theory\, Rev. Mod. Phys.\, 87:593–636\, 2015.\n
\n[3] Kirone Mallick\, Hiroki Moriya\, Tomohiro Sasamoto\,\nExact solution
of the macroscopic fluctuation theory for the symmetric exclusion process
\,\narXiv: 2202.05213\, to appear in Phys. Rev. Lett.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/112/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sohei Ashida (Gakushuin University)
DTSTART:20221025T140000Z
DTEND:20221025T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/113
DESCRIPTION:Title: Mathematics of molecular structures and dynamics\nby So
hei Ashida (Gakushuin University) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nI will talk about mathematically rigorous re
sults concerned with studies\nof molecules. The subject corresponds to N-b
ody problems of the\nSchrödinger equation from the standpoint of mathemat
ics. First\, we will\nconsider the spectrum and long-time asymptotic behav
iors\, focusing on\nscattering matrices of N-body Schrödinger equation. N
ext we will\nconsider quantitative studies based on the Born-Oppenheimer\n
approximation. Results related to estimates of electronic energy levels\ns
uch as the upper bound of electronic density and results concerned with\nt
he Hartree-Fock equation will be presented.\n\nReferences: [1] Kyushu J.\n
Math. 75\, 277-294 (2021) (arXiv:2002.07426) [2] Hiroshima Math. J.\, 52\,
\n177-216 (2022) (arXiv:1811.07527) [3] arXiv:2012.09397 to appear in\nToh
oku Math. J. [4] arXiv:2112.09521 to appear in Hokkaido Math. J. [5]\narXi
v:2205.10300\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Duch (Adam Mickiewicz University)
DTSTART:20221004T140000Z
DTEND:20221004T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/114
DESCRIPTION:Title: Flow equation approach to singular stochastic PDEs\nby
Paweł Duch (Adam Mickiewicz University) as part of One world IAMP mathema
tical physics seminar\n\n\nAbstract\nMost stochastic PDEs arising in physi
cs\, such as the KPZ equation describing the motion of a growing interface
or the stochastic quantization equation of the $\\Phi^4$ Euclidean QFT\,
are ill-posed in the classical analytic sense due to irregular nature of r
andom terms. Equations of this type are called singular. Regularization an
d renormalization are usually necessary to give mathematical meaning to su
ch equations. In the talk\, I will present a novel technique of solving si
ngular stochastic PDEs. The technique is based on the renormalization grou
p flow equation. It is applicable to a large class of parabolic or ellipti
c SPDEs with fractional Laplacian\, additive noise and polynomial non-line
arity. It covers equations in the whole super-renormalizable regime. A nic
e feature of the method is that it avoids the algebraic and combinatorial
problems arising in different approaches. Based on arXiv:2109.11380 and ar
Xiv:2201.05031.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Kopper (Ecole Polytechnique)
DTSTART:20221011T140000Z
DTEND:20221011T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/115
DESCRIPTION:Title: On asymptotically free scalar fields\nby Christoph Kopp
er (Ecole Polytechnique) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nI present recent work (Annales Henri Poincaré 2022)
analysing the flow equations of the renormalisation group in the mean fiel
d approximation. There it is shown that these equations for scalar fields
in four dimensional euclidean space\, have solutions which are UV asymptot
ically free. I comment on this result\, also in view of the literature\, i
n particular with regard to the triviality of \\varphi^4_4-theory. We clos
e with an outlook on future perspectives.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jian Ding (Peking University)
DTSTART:20220830T140000Z
DTEND:20220830T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/116
DESCRIPTION:Title: Repeated emergence of 4/3-exponent\nby Jian Ding (Pekin
g University) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nIn this talk\, I will describe the emergence of the 4/3-exponent
in two seemingly unrelated\nmodels: random distance of Liouville quantum
gravity and correlation length for the two-dimensional random field Ising
model. I will then explain that such 4/3-exponent\, while being unexpected
among respective communities even from a physics perspective\, has in fac
t been hinted in Leighton-Shor (1989) and Talagrand (2014) where the 4/3-e
xponent emerges in a random matching problem. Finally\, I will present the
heuristic computation which leads to the emergence of the 4/3-exponent.\n
\nWhile I will review related progress on these topics\, the two papers fe
aturing 4/3-exponent are with Subhajit Goswami and with Mateo Wirth.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Strohmaier (University of Leeds)
DTSTART:20220726T140000Z
DTEND:20220726T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/117
DESCRIPTION:Title: A mathematical analysis of Casimir interactions and determi
nant formulae\nby Alexander Strohmaier (University of Leeds) as part o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nI will explai
n a mathematical treatment of Casimir interactions of perfect conductors i
n which the Casimir energy is written as the trace of an operator without
the need for regularisations. I will also show some consequences of this a
pproach\, relations to microlocal analysis\, and will prove a trace formul
a that allows to compute the Casimir energy in terms of determinants of si
ngle layer operators. Such formulae have been derived by other methods in
the physics literature and we will show that all these approaches give the
same well defined Casimir energy.\n\n(Based on joint work with F. Hanisch
and A. Waters\, as well as numerical work with T. Betcke and X. Sun).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giovanni Felder (ETH Zürich)
DTSTART:20221101T140000Z
DTEND:20221101T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/118
DESCRIPTION:Title: Boltzmann's billiard and table tennis\nby Giovanni Feld
er (ETH Zürich) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nIn Boltzmann's billiard a particle moves in a half-plane subj
ect to a central force and is reflected elastically when it hits the bound
ary. Boltzmann took the central force to be the sum of a gravitational inv
erse-square-law force and a centrifugal term proportional to the\ninverse
cube of the distance to the centre. He formulated the expectation that exc
ept for special values of the parameters the system would be chaotic and w
ould obey his Ergodic Hypothesis. Recently Gallavotti and Jauslin showed t
hat the system is integrable if the\ncentrifugal term is omitted: it has a
second conserved quantity besides the energy. I will review this result a
nd show that this integrable Boltzmann system has the Poncelet property: i
f in a level set of the conserved quantities a trajectory is periodic then
all trajectories on the level set are periodic. As for the classical Ponc
elet theorem on inscribed-circumscribed polygons in Jacobi's interpretatio
n\, the result relies on the theory of elliptic curves. I will also presen
t some work in progress with Misha Feigin on Boltzmann's table tennis\, th
e three dimensional version of Boltzmann's integrable system\, and the rel
ation to QRT maps on biquadratic plane curves.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Dimock (SUNY at Buffalo)
DTSTART:20220816T140000Z
DTEND:20220816T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/119
DESCRIPTION:Title: Ultraviolet Stability for Quantum Electrodynamics in d=3\nby Jonathan Dimock (SUNY at Buffalo) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nWe report on results for quantum elect
rodynamics on a finite\nvolume Euclidean spacetime in dimension $d=3$. The
theory is formulated as a\nfunctional integral on a fine toroidal lattice
involving both fermion fields and\nabelian gauge fields. The main result
is that\, after renormalization\, the partition\nfunction is bounded unifo
rmly in the lattice spacing. This is a first step toward\nthe construction
of the model. The result is obtained by renormalization group\nanalysis p
ioneered by Balaban. A single renormalization group transformation\ninvolv
es block averaging\, a split into large and small field regions\, and an i
dentification of effective actions in the small field regions via cluster
expansions.\nThis leads to flow equations for the parameters of the theory
. Renormalization\nis accomplished by fine-tuning the initial conditions f
or these equations. Large\nfield regions need no renormalization\, but are
shown to give a tiny contribution.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martin Fraas (UC Davis)
DTSTART:20220802T140000Z
DTEND:20220802T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/120
DESCRIPTION:Title: Projections\, parallel transport and adiabatic theory\n
by Martin Fraas (UC Davis) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nI will give an overview of adiabatic theory with th
e focus on a geometric point of view. The talk will cover traditionally ad
iabatic theory\, adiabatic theory in many-body systems\, and a recent work
with W. De Roeck and A. Elgart on the adiabatic theory for disordered sys
tems.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anton Alekseev (University of Geneva)
DTSTART:20221115T140000Z
DTEND:20221115T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/121
DESCRIPTION:Title: Virasoro Hamiltonian spaces\nby Anton Alekseev (Univers
ity of Geneva) as part of One world IAMP mathematical physics seminar\n\n\
nAbstract\nIn this talk\, we consider Hamiltonian actions of the group of
diffeomorphisms of the circle. This is a semiclassical countepart of Viras
oro algebra actions in Conformal Field Theory. The main examples include V
irasoro coadjoint orbits (previously studied by Segal\, Kirillov\, Witten
and others) and moduli spaces of hyperbolic metrics on surfaces with bound
ary. Our study is motivated by recent progress in Jackiw-Teitelboim quantu
m gravity. In particular\, we give mathematical interpretation of some 2D
- 1D duality phenomena.\n\nThe talk is based on work in progress with Eckh
ard Meinrenken.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Avramidi (New Mexico Tech)
DTSTART:20221122T140000Z
DTEND:20221122T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/122
DESCRIPTION:Title: Spectral Asymptotics of Elliptic Operators on Manifolds
\nby Ivan Avramidi (New Mexico Tech) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nThe study of spectral properties of natur
al geometric elliptic partial differential operators acting on smooth sect
ions of vector bundles over Riemannian manifolds is a central theme in glo
bal analysis\, differential geometry and mathematical physics. Instead of
studying the spectrum of a differential operator $L$ directly one usually
studies its spectral functions\, that is\, spectral traces of some functio
ns of the operator\, such as the spectral zeta function $\\zeta(s)=\\Tr L^
{-s}$ and the heat trace $\\Theta(t)=\\Tr\\exp(-tL)$. The kernel $U(t\;x\,
x')$ of the heat semigroup $\\exp(-tL)$\, called the heat kernel\, plays a
major role in quantum field theory and quantum gravity\, index theorems\,
non-commutative geometry\, integrable systems and financial mathematics.
We review some recent progress in the study of spectral asymptotics. We st
udy more general spectral functions\, such as $\\Tr f(tL)$\, that we call
quantum heat traces. Also\, we define new invariants of differential opera
tors that depend not only on the their eigenvalues but also on the eigenfu
nctions\, and\, therefore\, contain much more information about the geomet
ry of the manifold. Furthermore\, we study some new invariants\, such as $
\\Tr\\exp(-tL_+)\\exp(-sL_-)$\, that contain relative spectral information
of two differential operators. Finally we show how the convolution of the
semigroups of two different operators can be computed by using purely alg
ebraic methods.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sinya Aoki (YITP\, Kyoto University)
DTSTART:20221213T140000Z
DTEND:20221213T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/123
DESCRIPTION:Title: Lattice QCD: Introduction\, results and challenges\nby
Sinya Aoki (YITP\, Kyoto University) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nLattice QCD is a non-perturbative definit
ion of QCD (Quantum ChromoDynamics) on a discrete spacetime.\nI first give
a comprehensive review on lattice QCD from the continuum QCD to numerica
l simulations.\nAs a representative of lattice QCD investigations\, I intr
oduce hadron mass calculations including an extraction of a hadron mass f
rom the hadron propagator\, its quark mass dependence and its extrapolat
ion to a zero lattice spacing limit. I also present the latest results on
hadron spectra including electromagnetic corrections.\nFinally I explain a
recent challenge in lattice QCD\, an extraction of hadron interactions su
ch as nuclear forces\, starting from a definition of potentials in QCD to
numerical results on scattering phase shifts.\nThroughout my talk\, I comm
ent on degrees of rigorousness of the lattice QCD method from time to time
.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Razvan Gurau (Universität Heidelberg)
DTSTART:20221108T140000Z
DTEND:20221108T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/124
DESCRIPTION:Title: Melonic field theories\nby Razvan Gurau (Universität H
eidelberg) as part of One world IAMP mathematical physics seminar\n\n\nAbs
tract\nLike random matrices\, random tensors exhibit a 1/N expansion\, but
their large N limit is more amenable to analytic computations. In particu
lar tensor field theories provide a new class of large N theories\, the so
called melonic theories. In this talk I will present an overview of recen
t results on such theories and discuss their implications.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Imbrie (University of Virginia)
DTSTART:20221206T140000Z
DTEND:20221206T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/125
DESCRIPTION:Title: On the Many-Body Localization Transition\nby John Imbri
e (University of Virginia) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nA quantum system is said to be many-body localized
(MBL) if it fails\nto thermalize. This can be understood as a consequence
of the\nexistence of an extensive set of local integrals of motion (LIOMs)
. In\n2016\, I showed that there is an MBL phase by constructing LIOMs at\
nstrong disorder (the proof depended on a certain assumption on level\nsta
tistics). The nature of the transition out of the MBL phase has\nbeen a su
bject of study and conjecture. In recent work with\nMorningstar and Huse (
PRB\, 2020)\, we utilize a series of\napproximations to develop specific R
G flow equations. These are\nsimilar to the Kosterlitz-Thouless (KT) flow
equations\, but there are\nimportant differences that place the MBL transi
tion in a new\nuniversality class.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Massimiliano Gubinelli (University of Oxford)
DTSTART:20221220T140000Z
DTEND:20221220T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/126
DESCRIPTION:Title: A stochastic analysis of EQFTs: the forward-backwards equat
ion for Grassmann measures\nby Massimiliano Gubinelli (University of O
xford) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\nI will report on a research program to use ideas from stochastic analys
is in the context of constructive quantum field theories. Stochastic analy
sis can be summarized as the study of measures on path space via push-forw
ard from Gaussian measures. The basic example is the Ito map which sends B
rownian motion to a Markov diffusion process solution to a stochastic diff
erential equation. Parisi-Wu stochastic quantisation can be understood as
a stochastic analysis of an Euclidean quantum field\, in the above sense.
In this talk I will focus on another way to introduce such an “Ito map
” which has connection to the continuous renormalization group a la Polc
hinski and which uses a forward-backwards stochastic differential equation
. In order to be able to give a full non-perturbative construction I will
focus on the case of Grassmann measures seen as instances of non-commutati
ve random fields.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Dereziński (University of Warsaw)
DTSTART:20230110T140000Z
DTEND:20230110T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/127
DESCRIPTION:Title: Dirac-Coulomb Hamiltonians\nby Jan Dereziński (Univers
ity of Warsaw) as part of One world IAMP mathematical physics seminar\n\n\
nAbstract\nI will discuss the theory of Dirac operators perturbed by the C
oulomb potential in an arbitrary dimension. These operators are interestin
g for several reasons:\n\n– They have obvious applications to atomic phy
sics.\n\n– If one neglects the mass term\, they are formally homogeneous
.\n\n– Depending on the coupling constant and dimension\, they exhibit s
everal distinct scaling behaviors (or if you prefer the high energy jargon
\, various “renormalization group flows”).\n\n– Their definition inv
olves subtle boundary conditions.\n\n– They are exactly solvable in term
s of Whittaker functions.\n\nMy talk will be based on recent joint work wi
th Błażej Ruba.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/127/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amanda Young (Technical University of Munich)
DTSTART:20230307T140000Z
DTEND:20230307T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/128
DESCRIPTION:Title: A bulk gap in the presence of edge states for a truncated H
aldane pseudopotential\nby Amanda Young (Technical University of Munic
h) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nI
n this talk\, we discuss the bulk gap for a truncated\n1/3-filled Haldane
pseudopotential for the fractional quantum Hall\neffect in the cylinder ge
ometry. In the case of open boundary\nconditions\, a lower bound on the sp
ectral gap (which is uniform in the\nvolume and particle number) accuratel
y reflects the presence of edge\nstates\, which do not persist into the bu
lk. A uniform lower bound for\nthe Hamiltonian with periodic boundary cond
itions is also obtain. Both\nof these bounds are proved by identifying inv
ariant subspaces to which\nspectral gap and ground state energy estimating
methods originally\ndeveloped for quantum spin Hamiltonians are applied.
Customizing the gap\ntechnique to the invariant subspace\, however\, we ar
e able to avoid the\nedge states and establish a more precise estimate on
the bulk gap in the\ncase of periodic boundary conditions. The same approa
ch can also be\napplied to prove a bulk gap for the analogously truncated
Haldane\npseudopotential with maximal half filling\, which describes a str
ongly\ncorrelated system of spinless bosons in a cylinder geometry. This i
s\nbased off joint work with S. Warzel.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lingrui Ge (University of California\, Irvine)
DTSTART:20230404T140000Z
DTEND:20230404T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/129
DESCRIPTION:Title: Multiplicative Jensen’s formula and quantitative global t
heory for ID quasiperiodic operators\nby Lingrui Ge (University of Cal
ifornia\, Irvine) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nWe prove multiplicative Jensen’s formula and establish qua
ntitative global theory for analytic one-frequency Schrodinger operators.
We will also discuss the motivations and further applications.\nThis is ba
sed on a joint work with Jiangong You\, Svetlana Jitomirskaya and Qi Zhou.
\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Maes (KU Leuven)
DTSTART:20230221T140000Z
DTEND:20230221T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/130
DESCRIPTION:Title: Nonequilibrium extension of Third Law\nby Christian Mae
s (KU Leuven) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nThe Nernst-Planck Postulate (Third Law of Thermodynamics stating
that the entropy becomes zero at zero temperature) has a different status
from the other Laws: it is not a consequence of the general structure of
statistical thermodynamics\, it can fail\, and it does not carry a straig
htforward dynamic or kinetic derivation when it does hold. In this talk w
e consider the latter question\, by extending the Third Law to nonequilibr
ium jump processes. We give sufficient conditions in a Nonequilibrium Ner
nst Theorem\, that the operationally defined excess heat vanishes at absol
ute zero\, and from counter examples\, we understand that those conditions
are well on target. We give an example of a zero-temperature nonequilibr
ium transition where the heat capacity abruptly diverges as a function of
the chemical potential. The main ingredients in the proof are a formulati
on of the quasistatic relaxation between nonequilibrium steady conditions\
,d a combined application of the matrix tree and the matrix forest theorem
.\n\nJoint work with Faezeh Khodabandehlou and Karel Netocny.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/130/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Elgart (Virginia Tech)
DTSTART:20230207T140000Z
DTEND:20230207T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/131
DESCRIPTION:Title: Localization of the random XXZ spin chain in fixed energy i
ntervals\nby Alexander Elgart (Virginia Tech) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nA Schrödinger operator $H$
is known to exhibit quasi-locality: Matrix elements of analytic functions
of $H$ decay exponentially away from the diagonal. Localization for a rand
om Schrödinger operator can be expressed as an extension of this feature
to Borel measurable functions with support in the region of localization.\
n\n\nWe show that the spin-$\\frac12$ XXZ random chain Hamiltonian $H_{XXZ
}$ manifests a suitably defined notion of quasi-locality as well. We explo
it this property to prove that $H_{XXZ}$ exhibits localization in any fixe
d energy interval (expressed as quasi-locality for Borel measurable functi
ons of $H_{XXZ}$ with support in the energy interval). Localization is pr
oved in a nontrivial region of the parameter space\, which includes weak i
nteraction and strong disorder regimes\, and is independent of the size of
the system\, depending only on the energy interval.\n\n\nBased on a joint
work with Abel Klein\, https://arxiv.org/abs/2210.14873\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/131/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Hainzl (Mathematisches Institut der Universität Münche
n)
DTSTART:20230124T140000Z
DTEND:20230124T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/132
DESCRIPTION:Title: Correlation energy of an electron gas in the mean-field app
roximation\nby Christian Hainzl (Mathematisches Institut der Universit
ät München) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nThe correlation energy of a high density fermionic Coulomb gas\,
called Jellium\, is expected to be given by the Gell-Mann Brueckner formu
la. I will discuss an analogue of this formula for the mean-field regime.
I present a rigorous upper bound established by variational methods in the
case of Coulomb interaction. I will further review similar results for mo
re regular potentials\, which is meanwhile well understood for particles i
n a fixed box. The talk is based on joint work with Martin Christiansen an
d P. T. Nam.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/132/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hermann Schulz-Baldes (Friedrich-Alexander-Universitaet Erlangen-N
uernberg)
DTSTART:20230321T140000Z
DTEND:20230321T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/133
DESCRIPTION:Title: Pseudo-gaps for random hopping models\nby Hermann Schul
z-Baldes (Friedrich-Alexander-Universitaet Erlangen-Nuernberg) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nFor one-dimensi
onal random Schrödinger operators\, the integrated density of states\nis
known to be given in terms of the (averaged) rotation number of the Pr¨uf
er phase\ndynamics. This paper develops a controlled perturbation theory f
or the rotation number\naround an energy at which all the transfer matrice
s commute and are hyperbolic. Such\na hyperbolic critical energy appears i
n random hopping models. The main result is a\nHölder continuity of the r
otation number at the critical energy that implies the existence\nof a pse
udo-gap. The proof uses renewal theory. The result is illustrated by numer
ics.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/133/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Toninelli (Univ. Paris Dauphine)
DTSTART:20230516T140000Z
DTEND:20230516T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/134
DESCRIPTION:Title: Bootstrap percolation and kinetically constrained models: u
niversality results\nby Cristina Toninelli (Univ. Paris Dauphine) as p
art of One world IAMP mathematical physics seminar\n\n\nAbstract\nRecent y
ears have seen a great deal of progress in understanding the behavior of b
ootstrap percolation (BP) models\, a particular class of monotone cellular
automata. In the initial configuration sites are occupied with probabilit
y p. The evolution of BP occurs at discrete times: empty sites stay empty
and occupied sites are emptied iff a certain model dependent neighborhood
is already empty. In the Euclidean lattice there is now a complete underst
anding of the large time evolution with a universality picture for the cri
tical behavior. Much less is known for their non-monotone stochastic count
erpart\, namely kinetically constrained models (KCM). In KCM each vertex i
s updated independently at rate p (respectively 1-p) to occupied (respect
ively empty) iff it could be emptied in the next step by the bootstrap mod
el. In the last two decades KCM have been the subject of intensive researc
h both in physics and mathematics literature. The main motivation is that\
, for certain choices of the constraints\, when p goes to zero KCM display
some of the most striking features of the liquid/glass transition. Indeed
\, they were originally introduced in the 80's to support the free volume
theories and later on used as the simplest lattice models reproducing the
dynamical facilitation scenario. In this seminar I will discuss some recen
t rigorous results on the characteristic time scales of KCM as p goes to
zero as well as the connection with the critical behavior of the correspon
ding BP models.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Flora Koukiou (Cergy–Pontoise University)
DTSTART:20230530T140000Z
DTEND:20230530T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/135
DESCRIPTION:Title: Freezing and Entropy of the Log-correlated Random fields\nby Flora Koukiou (Cergy–Pontoise University) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nFreezing is a concept that
was introduced more than thirty years ago and has since been\nstudied in t
he context of statistical mechanics and\, more recently\, has been related
to multifractality and\nextreme value statistics.\nIn this talk\, after a
short survey\, we define freezing in relation to the behaviour of the e
ntropy of the Gibbs measures for several mean-field models.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scott Armstrong (New York University)
DTSTART:20230613T140000Z
DTEND:20230613T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/136
DESCRIPTION:Title: Anomalous diffusion for passive scalar equations by fractal
homogenization\nby Scott Armstrong (New York University) as part of O
ne world IAMP mathematical physics seminar\n\n\nAbstract\nIn this talk I w
ill describe the main ideas in a recent joint work with Vlad Vicol. We con
struct an explicit divergence-free vector field on the torus\, which is Ho
lder continuous with exponent almost 1/3 in space and time\, such that the
corresponding advection-diffusion equation admits anomalous diffusion\, f
or all initial data\, along a subsequence of diffusivities tending to zero
. The construction builds into the vector field a countable sequence of "a
ctive scales" which have resonances with the scalar\, resulting in a casca
de of energy moving to smaller scales. The proof is a renormalization sche
me\, based on homogenization methods.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/136/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michał Wrochna (Cergy Paris University)
DTSTART:20230418T140000Z
DTEND:20230418T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/137
DESCRIPTION:Title: Thermodynamics of quantum fields on rotating black hole spa
cetimes\nby Michał Wrochna (Cergy Paris University) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nWhat is the final qua
ntum state arising from black hole collapse\, and what are its thermodynam
ical properties? In somewhat idealized models like the Kerr metric\, the c
onjectural candidate is the Unruh state. While it is not an equilibrium st
ate\, asymptotically one expects the occurrence of Hawking temperature. In
this talk I will review recent results that give a rigorous definition an
d construction based on scattering theory. While the case of bosonic field
s on Kerr spacetime is still open\, it turns out that it is possible to pr
ove many physical properties of the Unruh state for instance for massless
fermions. The talk is based on joint work with Christian Gérard and Dietr
ich Häfner.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikita Nekrasov (Simons Center for Geometry and Physics)
DTSTART:20230502T140000Z
DTEND:20230502T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/138
DESCRIPTION:Title: Qouroboros: Quantum mechanics from supersymmetric quantum f
ield theory\nby Nikita Nekrasov (Simons Center for Geometry and Physic
s) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nW
avefunctions of the stationary states of some quantum mechanical systems c
an be exactly computed using supersymmetric gauge theory in dimension 4. I
will explain theory and practice of the method.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Huse (Princeton)
DTSTART:20230919T140000Z
DTEND:20230919T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/139
DESCRIPTION:Title: Many-body localization\nby David Huse (Princeton) as pa
rt of One world IAMP mathematical physics seminar\n\n\nAbstract\nMany-body
localization (MBL) is Anderson localization of many interacting quantum\n
degrees of freedom in highly-excited states at conditions that correspond
to a nonzero entropy\ndensity at thermal equilibrium. The opposite of MBL
is thermalization\, where the isolated\nquantum many-body system successfu
lly acts as a thermal bath for itself\, bringing all of its\nsmall subsyst
ems to thermal equilibrium with each other via the unitary quantum dynamic
s of\nthe closed system. For finite systems with short-range interactions
the transition from\nthermalization to MBL occurs in two stages as the int
eractions are reduced: First is a smooth\ncrossover to a “glassy” pret
hermal MBL regime\, where the thermalization time of a large\nsystem becom
es extremely large but not infinite. Then\, at still weaker interaction is
the\ndynamical phase transition in to the MBL phase\, which in many cases
occurs at a strength of\ninteractions that is so small that it is thermod
ynamically insignificant in the limit of large\nsystems\, even though it h
as strong long-time dynamical effects.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/139/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcello Porta (SISSA)
DTSTART:20230905T140000Z
DTEND:20230905T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/140
DESCRIPTION:Title: Universality of Transport in Many-Body Lattice Models\n
by Marcello Porta (SISSA) as part of One world IAMP mathematical physics s
eminar\n\n\nAbstract\nIn this talk I will discuss rigorous results about t
he charge transport properties of gapless interacting fermionic lattice mo
dels\, with a particular emphasys on the emergence of universality at the
macroscopic scale. I will outline a strategy that has been used over the y
ears to compute response functions for a class of gapless models\, includi
ng one-dimensional metals and two and three-dimensional semimetals. The ap
proach is based on the combination of: analytic continuation of real-time
response functions to imaginary times\; renormalization group analysis of
imaginary-time correlations and resolution of the scaling limit\; lattice
conservation laws and Ward identities to prove universality of transport c
oefficients. I will focus on the application to the edge response function
of interacting 2d quantum Hall systems\, defined starting from the linear
response ansatz. In the last part of the talk\, I will discuss how the fr
amework can be used go beyond linear response\, for gapped systems at low
temperatures.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Lemm (University of Tübingen)
DTSTART:20230627T140000Z
DTEND:20230627T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/141
DESCRIPTION:Title: Light cones for open quantum systems\nby Marius Lemm (U
niversity of Tübingen) as part of One world IAMP mathematical physics sem
inar\n\n\nAbstract\nWe consider non-relativistic Markovian open quantum dy
namics (MOQD) in continuous space. We show that\, up to small-probability
tails\, the supports of quantum states evolving under MOQD propagate with
finite speed in any finite-energy subspace. More precisely\, if the initia
l quantum state is localized in space\, then any finite-energy part of the
solution of the von Neumann-Lindblad equation is approximately localized
inside an energy-dependent light cone. We also obtain an explicit upper bo
und on the slope of this light cone (i.e.\, on the maximal speed). The gen
eral method can be used to derive propagation bounds for a variety of othe
r quantum systems including Lieb-Robinson bounds for lattice bosons. Based
on joint works with S. Breteaux\, J. Faupin\, D.H. Ou Yang\, I.M. Sigal\,
and J. Zhang.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Horng-Tzer Yau (Harvard)
DTSTART:20231031T140000Z
DTEND:20231031T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/142
DESCRIPTION:Title: Spectral gap and two point function estimates for mean-f
ield spin glass models\nby Horng-Tzer Yau (Harvard) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nIn this lecture\, we
’ll review some recent results regarding spectral gaps and logarithmic
Sobolev inequality for Glauber dynamics of mean-field spin glass models
. In particular\, we will present a method to prove that the spectral gap
of the Glauber dynamics is of order one at sufficiently high temperature
. In addition\, we will review certain estimates on two point functions
for the SK model satisfying a modified AT condition.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sourav Chatterjee (Stanford)
DTSTART:20231003T140000Z
DTEND:20231003T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/143
DESCRIPTION:Title: Spin glass phase in the Edwards-Anderson model at zero temp
erature\nby Sourav Chatterjee (Stanford) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nWhile the analysis of mean-field
spin glass models has seen tremendous progress in the last twenty years\,
lattice spin glasses have remained largely intractable. I will talk about
recent progress on this topic\, giving the first proof of glassy behavior
in the Edwards-Anderson model of lattice spin glasses.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alberto Cattaneo (University of Zurich)
DTSTART:20231017T140000Z
DTEND:20231017T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/144
DESCRIPTION:Title: A cohomological view of quantum field theory\nby Albert
o Cattaneo (University of Zurich) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nI will review the Batalin–Vilkovisky forma
lism and its\ncognates which present classical and quantum field theory vi
a a\nflexible formalism in which spaces of fields are presented as\ncomple
xes whose cohomology returns the physical content. Different but\nequivale
nt complexes may be used\, which turns out to be important\nconceptuallly
and in practice. Examples will be discussed.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/144/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nguyen Viet Dang (Sorbonne University)
DTSTART:20231114T140000Z
DTEND:20231114T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/145
DESCRIPTION:Title: The Phi43 measure on Riemannian manifolds\nby Nguyen Vi
et Dang (Sorbonne University) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nI will describe a joint work with Bailleul\, Fer
dinand and To where we construct the $\\phi^4_3$ quantum field theory meas
ure on compact Riemannian 3-manifolds\, as invariant measure of some stoch
astic partial differential equation\, I will try to motivate the approach
and show many examples. This gives an example of nonperturbative\, interac
ting\, non topological quantum field theory constructed on 3 manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Torben Krüger (Erlangen)
DTSTART:20231212T140000Z
DTEND:20231212T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/146
DESCRIPTION:Title: Merging Singularity in the Normal Matrix Model\nby Torb
en Krüger (Erlangen) as part of One world IAMP mathematical physics semin
ar\n\n\nAbstract\nThe two-dimensional one-component plasma is a particle s
ystem in the plane with long-range logarithmic interactions. At a specific
temperature the system is equivalent to the eigenvalue ensemble of a norm
al random matrix model. In equilibrium the particles form droplets when pl
aced in an external potential. Using the Riemann-Hilbert approach we deter
mine the local statistical behaviour of the particles at the merging point
of droplets and observe an anisotropic scaling behaviour with particles b
eing much further apart in the direction of merging than the perpendicular
direction\, effectively generating a one dimensional particle system. Ver
y close to the point of merger this leads to correlations described by the
Painleve II kernel that is also present in certain unitary matrix ensembl
es. Furthermore\, in the vicinity of the singularity sine kernel statistic
s\, Ginibre edge and bulk statistics\, as well as the local statistics of
a Coulomb gas confined to a small strip are observed. Our comprehensive de
scription of the merging singularity lends support to the conjecture that
the hierarchy of local particle statistics at singularities of the particl
e density within two-dimensional Coulomb gases can be characterised in ter
ms of the corresponding hierarchy for one-dimensional invariant ensembles.
\n\nThis is joint work with Meng Yang and Seung-Yeop Lee\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei-Min Wang (Shanghai / CNRS)
DTSTART:20240206T140000Z
DTEND:20240206T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/147
DESCRIPTION:Title: On the dynamics of nonlinear random and quasi-periodic syst
ems\nby Wei-Min Wang (Shanghai / CNRS) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nWe discuss time evolution of
nonlinear random and quasi-periodic systems and\nelaborate on their simila
rities. Examples of such systems include the nonlinear random \nand the no
nlinear quasi-periodic Schr\\"odinger equations on the lattice. These prob
lems \nare related to and are partly motivated by many body localization.\
n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Charles Newman (NYU -- Courant)
DTSTART:20240109T140000Z
DTEND:20240109T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/148
DESCRIPTION:Title: Brownian Excursions\, Ising Models and the Riemann Hypothes
is -- Possible Connections\nby Charles Newman (NYU -- Courant) as part
of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe distrib
ution of the maximum of a Brownian excursion (BE)\,\nknown explicitly sinc
e 1976\, is related\nto the Riemann zeta and ksi functions. We discuss how
if one could\n*properly* relate either ksi or BE to an\nIsing model (IM)\
, the Riemann Hypothesis would follow from the 1952\ntheorem of Lee and Ya
ng about zeros of\nIM partition functions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sebastien Ott (EPFL)
DTSTART:20231128T140000Z
DTEND:20231128T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/149
DESCRIPTION:Title: Asymptotic expansion for classical O(N) models\nby Seba
stien Ott (EPFL) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nthe spin O(N) model on the cubic lattice at small temperature
can be seen (at least at a formal level) as a perturbation of a (N-1) vec
torial GFF on the lattice. As a result\, one expects that it is possible t
o extract precise informations about many observables from the GFF. A firs
t result going in this direction is to establish that one can expand quant
ities such as the spontaneous magnetisation in Taylor series (in the tempe
rature)\, and that the coefficients of this series are the one obtained by
formal power series expansion.\nThis was acheived in 1981 by Bricmont\, F
ontaine\, Lebowitz\, Lieb\, and Spencer in the abelian case of the XY (O(2
)) model\, using a regularized version of Gaussian integration by part and
infrared bounds coming from reflection positivity of the model. I will br
iefly review their approach\, and will present an extension to general N i
n dimension 3 and higher\, highlighting what are the requiered new inputs.
\nBased on joint work with A.Giuliani\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rainer Verch (Leipzig)
DTSTART:20240305T140000Z
DTEND:20240305T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/150
DESCRIPTION:Title: Moving away from equilibrium\nby Rainer Verch (Leipzig)
as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe
seminar takes up on several aspects related to the Unruh effect. \nIn a n
utshell\,\n a mathematically rigorous treatment of the Unruh effect by de
Biévre \nand Merkli has shown\n that a quantum mechanical\, finite-ener
gy level "detector" system \nwhich moves with constant\n acceleration wit
h respect to an inertial system\, and is locally \ncoupled to a quantum fi
eld\n in the inertial vacuum state\, will asymptotically for large times
\napproximate a Gibbs (thermal\n equilibrium) state. In a new work with A
.G. Passegger\, we show that \nthe behaviour of such\n a detector system
is quite different if it moves with constant \nvelocity with respect to\n
an inertial system in which a quantum field is in a KMS state\, and \nto
which the detector is\n locally coupled. Concretely\, combining previous
results known in the \nliterature\, we show that\n for any quantum field
theory in Minkowski spacetime\, two primary \nstates KMS states with respe
ct\n to different inertial frames are disjoint (belong to inequivalent \n
folia of states) if they fulfill\n a suitable clustering condition. The q
uantized free scalar field is \nan example where the conditions\n are ful
filled. Put differently\, Lorentz symmetry is broken (not \nunitarily impl
ementable) in\n quantum field theory in inertial thermal (KMS) representa
tions. \n(This seems to belong to "general wisdom"\,\n but appears to hav
e never been fully proved in the literature.) We \nargue\, along the lines
of G. Sewell\,\n that the detector moving with constant velocity against
the thermal \nbackground of a quantum field\n in an inertial KMS state\,
will not asymptotically thermalize - at \nleast the return to equilibrium
\n arguments are not applicable in this context because of the broken \nL
orentz symmetry in inertial\n KMS states. We also argue that this corrobo
rates the view expressed \nby D. Buchholz and R. Verch\, and others\,\n t
hat the Unruh effect is not due to thermal contact of the detector \nwith
a "heat bath" supplied by the\n quantum field\, but is rather due to conv
ersion of work to heat \nthrough the coupling of the\n detector to the qu
antum field and the externally driven motion of \nthe detector.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/150/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claude-Alain Pillet (Toulon)
DTSTART:20240319T140000Z
DTEND:20240319T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/151
DESCRIPTION:Title: Adiabatic Time Evolution and Quasi-Static Processes in Tran
slation-Invariant Quantum Systems\nby Claude-Alain Pillet (Toulon) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe stud
y the slowly varying\, non-autonomous dynamics of a translation-invariant
quantum spin system on the lattice Z^d . This system is assumed to be init
ially in thermal equilibrium\, and we consider realizations of quasi-stati
c processes in the adiabatic limit. By combining the Gibbs variational pri
nciple with the notion of quantum weak Gibbs states\, we establish a numbe
r of general structural results regarding such realizations. In particular
\, we show that such a quasi-static process is incompatible with the prope
rty of approach to\nequilibrium as discussed by V. Jaksic in his talk on M
arch 22\, 2022.\n\nThis is a joint work with V. Jaksic and C. Tauber\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/151/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yoh Tanimoto (Tor Vergata)
DTSTART:20240123T140000Z
DTEND:20240123T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/152
DESCRIPTION:Title: Wightman fields for two-dimensional conformal field theory<
/a>\nby Yoh Tanimoto (Tor Vergata) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nFor a class of two-dimensional full conform
al field theory\, we construct\nWightman fields generating the whole theor
y. The construction is based\non non-local charged primary fields that int
ertwine superselection\nsectors of the chiral components. We discuss the c
orresponding Schwinger\nfunctions that should satisfy the Osterwalder-Schr
ader axioms and\nrelations with possibly massive models by the perturbatio
n of the\nspacetime symmetry.\n(joint with M.S. Adamo\, L. Giorgetti\, C.
Jäkel and Y. Moriwaki)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/152/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kasia Rejzner (York)
DTSTART:20240416T140000Z
DTEND:20240416T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/153
DESCRIPTION:Title: Renormalisation of gauge theories in perturbative algebraic
quantum field theory\nby Kasia Rejzner (York) as part of One world IA
MP mathematical physics seminar\n\n\nAbstract\nIn this talk I will briefly
introduce the framework of\nperturbative algebraic quantum field theory (
pAQFT) and explain how it\ncan be used in quantisation of gauge theories.
This requires methods\nfrom functional analysis as well as homological alg
ebra. Some new\ndevelopments in this area involve treatment of theories on
manifolds\nwith boundary\, including the "boundary at infinity." The latt
er case\nallows the discussion of asymptotic symmetries\, e.g. in quantum\
nelectrodynamics.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/153/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Stottmeister (Hannover)
DTSTART:20240220T140000Z
DTEND:20240220T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/154
DESCRIPTION:Title: Embezzlement of entanglement\, quantum fields\, and the cla
ssification of von Neumann algebras\nby Alexander Stottmeister (Hannov
er) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\n
We discuss the embezzlement of entanglement in the setting of von Neumann
algebras and its relation to the classification of the latter\, as well as
its application to relativistic quantum field theory. Embezzlement (of en
tanglement)\, introduced by van Dam and Hayden\, denotes the task of produ
cing any entangled state to arbitrary precision from a shared entangled re
source state\, the embezzling state\, using local operations without commu
nication while perturbing the resource arbitrarily little. \nWe show that
Connes' classification of type III von Neumann algebras can be given a qua
ntitative operational interpretation in terms of embezzlement. In particul
ar\, this quantification implies that all type III factors\, apart from so
me type III_0 factors\, host embezzling states. In contrast\, semifinite f
actors (type I or II) cannot host embezzling states. \nSpecifically\, type
III_1 factors are characterized as "universal embezzlers“\, meaning eve
ry normal state is embezzling. The latter observation provides a simple ex
planation as to why relativistic quantum field theories maximally violate
Bell inequalities.\nOur results follow from a one-to-one correspondence be
tween embezzling states and invariant states on the flow of weights.\n\nTh
is is joint work with Lauritz van Luijk\, Reinhard F. Werner\, and Henrik
Wilming.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/154/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aernout van Enter (Groningen)
DTSTART:20240430T140000Z
DTEND:20240430T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/155
DESCRIPTION:Title: Dyson models: One-sided and two-sided aspects\nby Aerno
ut van Enter (Groningen) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nI will discuss Dyson models\, long-range one-dimensio
nal Ising spin systems with ferromagnetic pair interactions.\nI first will
discuss how they provide an example for non-equivalence of one-sided and
two-sided regularity properties.\nThe switching between one-sided and tw
o-sided descriptions lies at the base of Thermodynamic Formalism\, which d
escribes various Dynamical Systems as one-dimensional statistical mechanic
s models\, usually with fast decaying interactions..\nIn particular at low
temperatures there can be differences in continuity properties between
a measure's one-sided and two-sided conditional probabilities. Gibbs mea
sures for summable interactions can be characterised by the continuity of
their two-sided (from both left and right) conditional probabilities\, Th
e one-sided analogue\, where a spin depends continuously on the left only
(the past)\, forms the class of g-measures. It was known before that a
g-measure need not be a Gibbs measure. We show the opposite\, that a Gibbs
measure for a summable interaction\, and in particular for a low-tempera
ture Dyson interaction\, can fail to be a g-measure.\n\nIn a somewhat di
fferent usage\, one-sided versus two-sided systems describes models on a
half-line as compared with the model on the whole line.\nOne can consider
the model on the whole line as a model on two half-lines with a coupling
term between the half-lines.\nProperties of this coupling term\, connecti
ng either ordered or disordered half-lines\, such as its boundedness\, and
integrability\, explain the properties of the "metastates" -- the dis
tribution over limit states- of the model with random boundary conditions
at low temperatures.\nAlso they explain the continuity\, or the lack ther
eof\, of the eigenfunctions of Ruelle transfer operators at high temperatu
res.\nContinuity of these eigenfunctions is a sufficient\, but not necessa
ry\, condition for continuity of the one-sided conditional probabilities.
\nWe show that in certain circumstances the Radon-Nikodym density on the
half-line\, between coupled and decoupled Gibbs measures -- which is equa
l to the transfer operator eigenfunction--\, can have stronger regularity
properties than the analogous Radon-Nikodym density on the whole line.\n\
nThe talk is based on joint works with Rodrigo Bissacot\, Eric Endo\, Ro
berto Fernández\, Arnaud Le Ny\, Mirmukhsin Makhmudov and Evgeny Verbitsk
iy\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephan De Bièvre (Lille)
DTSTART:20240618T140000Z
DTEND:20240618T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/156
DESCRIPTION:Title: Assessing optical nonclassicality with the quadrature coher
ence scale\nby Stephan De Bièvre (Lille) as part of One world IAMP ma
thematical physics seminar\n\n\nAbstract\nIn quantum optics\, a state is s
aid to be ``classical’’ if it is a mixture of coherent states. Equival
ently\, such states have a positive Glauber-Sudarshan P-function. It is a
longstanding problem in quantum optics\, that has attracted renewed attent
ion in the context of quantum information theory\, to efficiently identify
/characerize the convex set of all such states. After reviewing some of th
e history of this problem\, we shall in this talk present the ``quadrature
coherence scale’’\, which provides a measure of non-classicality (in
the above sense)\, and detail some of its merits. We will further briefly
discuss the analogous problems of determining the set of all Wigner-positi
ve states and of all Kirkwood-Dirac positive states.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noé Cuneo (LPSM)
DTSTART:20240402T140000Z
DTEND:20240402T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/157
DESCRIPTION:Title: Large deviations of return times and related entropy estima
tors on shift spaces\nby Noé Cuneo (LPSM) as part of One world IAMP m
athematical physics seminar\n\n\nAbstract\nThe study of return times in dy
namical systems has a long history\, and their role as entropy estimators
is well established. While considerable attention has been devoted to the
corresponding Law of Large Numbers\, Central Limit Theorem and pressure fu
nction in the literature\, surprisingly little was known about their large
deviations. In fact\, only local versions of the Large Deviation Principl
e (LDP) were obtained\, under some rather restrictive assumptions. I will
talk about a recent work in collaboration with Renaud Raquépas (arXiv:230
6.05277\, to appear in Commun. Math. Phys.)\, where we prove that return t
imes satisfy the full LDP for a large class of invariant measures on shift
spaces. Our assumptions cover in particular irreducible Markov chains\, e
quilibrium measures for Bowen-regular potentials\, invariant Gibbs states
for absolutely summable interactions in statistical mechanics (including i
n the phase-transition regime)\, and some repeated quantum measurement pro
cesses. As we will see in a striking example\, the rate function governing
the LDP can be nonconvex.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/157/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roderich Tumulka (Tübingen)
DTSTART:20240514T140000Z
DTEND:20240514T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/158
DESCRIPTION:Title: Time evolution of closed macroscopic quantum systems toward
s thermal equilibrium\nby Roderich Tumulka (Tübingen) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nSuppose we make a h
ot brick and a cold brick touch each other and\nisolate them from the rest
of the world. Then\, of course\, energy will be\ntransported from the hot
ter to the cooler until they reach the same\ntemperature. This example ill
ustrates the sense in which an isolated\,\nmacroscopic quantum system in a
pure state will approach thermal\nequilibrium. Here\, different macro-sta
tes correspond to mutually\northogonal subspaces of Hilbert space\, each o
f very high dimension\,\nthermal equilibrium to one of these subspaces\, a
nd entropy to the\nlogarithm of the dimension. I will describe results con
cerning the\nunitary time evolution of such systems towards thermal equili
brium\, the\nrole played by a version of the eigenstate thermalization hyp
othesis\,\nand some open questions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/158/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Niels Benedikter (Milan)
DTSTART:20240604T140000Z
DTEND:20240604T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/159
DESCRIPTION:Title: Bosonization of Large Systems of Interacting Fermions\n
by Niels Benedikter (Milan) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nThe behavior of electrons in a metal presents a wi
de variety of emergent behavior including a number of phase transitions. T
he mean-field scaling limit acts as a simplified model capturing part of t
his complexity. In this limit\, results going beyond the precision of Hart
ree-Fock theory have recently been obtained by bosonization methods. I wil
l review the expansion of the ground state energy and present results exte
nding to the dynamics and momentum distribution of excitations.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Wald (Chicago)
DTSTART:20240730T140000Z
DTEND:20240730T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/160
DESCRIPTION:Title: The Memory Effect and Infrared Divergences\nby Robert W
ald (Chicago) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nThe "memory effect" is the permanent relative displacement of te
st particles after the passage of gravitational radiation. It is associate
d with both the propagation of massive bodies out to timelike infinity ("o
rdinary memory") or the propagation of radiation out to null infinity ("nu
ll memory"). The memory effect can be characterized by the failure of the
shear tensor at order 1/r to return to zero at late times\, even though it
is "pure gauge." Closely analogous effects occur in electromagnetism\, wh
ere the vector potential at order 1/r fails to return to zero even though
it is "pure gauge." In both cases\, the Fourier transform of the radiative
field has divergent behavior at low frequencies. This gives rise to infra
red divergences (i.e.\, infinite numbers of "soft" gravitons/photons) in t
he quantum field theory description if one attempts to describe these stat
es as vectors in the usual Fock Hilbert space representation. To obtain a
mathematically sensible quantum scattering theory\, one must allow states
with nonvanishing memory in the "in" and "out" Hilbert spaces. An elegant
solution to this problem in massive quantum electrodynamics was given by K
ulish and Fadeev\, who constructed a Hilbert space of incoming/outgoing ch
arged particle states that are "dressed" with radiative fields of correspo
nding memory\, so as to yield vanishing large gauge charges at spatial inf
inity. However\, we show that this type of construction fails in quantum g
ravity. The primary underlying reason is that the ``dressing'' contributes
to null memory\, thereby invalidating the construction of eigenstates of
large gauge charges. In quantum gravity\, there does not appear to be any
choice of (separable) Hilbert space of incoming/outgoing states that can a
ccommodate all scattering states.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/160/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Mitrouskas (ISTA)
DTSTART:20240924T140000Z
DTEND:20240924T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/161
DESCRIPTION:Title: Low-Energy Properties of the Strongly Coupled Polaron\n
by David Mitrouskas (ISTA) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nThe Fröhlich Hamiltonian models an electron intera
cting with a polarizable medium\, described by a nonrelativistic quantum f
ield. In the strong coupling regime\, the ground state energy of the quant
um model is known to converge to that of its semiclassical counterpart\, w
here the field is treated classically. This talk will review recent result
s on the low-energy properties of the Fröhlich Hamiltonian in this regime
. The discussion includes an asymptotic series expansion for the eigenvalu
es in the confined model\, and the existence of excited bound states in th
e translation-invariant model at fixed total momentum.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/161/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sky Cao (MIT)
DTSTART:20240910T140000Z
DTEND:20240910T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/162
DESCRIPTION:Title: Global well-posedness of stochastic Abelian-Higgs in two di
mensions\nby Sky Cao (MIT) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nThere has been much recent progress on the loca
l solution theory for geometric singular SPDEs. However\, the global theor
y is still largely open. In my talk\, I will discuss the global well-posed
ness of the stochastic Abelian-Higgs model in two dimensions\, which is a
geometric singular SPDE arising from gauge theory. The proof is based on a
new covariant approach\, which consists of two parts: First\, we introduc
e covariant stochastic objects\, which are controlled using covariant heat
kernel estimates. Second\, we control nonlinear remainders using a covari
ant monotonicity formula\, which is inspired by earlier work of Hamilton.
Joint work with Bjoern Bringmann.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/162/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simon Becker (ETH Zürich)
DTSTART:20241022T140000Z
DTEND:20241022T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/163
DESCRIPTION:Title: Magic moire materials\nby Simon Becker (ETH Zürich) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nI will
review recent advancements in the field of twistronics. \nTwistronics inv
estigates how varying the angle between layers of two-dimensional material
s can significantly alter their electrical properties.\nNotably\, twisted
bilayer graphene exhibits a broad spectrum of different strongly correlate
d phases of matter\, ranging from non-conductive to superconductive\, depe
nding on the specific twist angle between its layers. \nThese remarkable e
ffects are observed at particular angles known as magic angles.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Angela Capel Cuevas (Cambridge)
DTSTART:20241105T140000Z
DTEND:20241105T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/164
DESCRIPTION:Title: Rapid thermalisation of quantum dissipative many-body syste
ms\nby Angela Capel Cuevas (Cambridge) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nQuantum systems typically reach the
rmal equilibrium when in weak contact with a large external bath. Understa
nding the speed of this thermalisation is a challenging problem\, especial
ly in the context of quantum many-body systems where direct calculations a
re intractable. The usual way of bounding the speed of this process is by
estimating the spectral gap of the dissipative generator\, but this does n
ot always yield a reasonable estimate for the thermalisation time. When th
e system satisfies instead a modified logarithmic Sobolev inequality (MLSI
)\, the thermalisation time is at most logarithmic in the system size\, y
ielding wide-ranging applications to the study of many-body in and out-of-
equilibrium quantum systems\, such as stability against local perturbation
s (in the generator)\, efficient preparation of Gibbs states (the equilibr
ia of these processes)\, etc.\n\nIn this talk\, I will present an overview
on a strategy to prove that a system satisfies a MLSI provided that corre
lations decay sufficiently fast between spatially separated regions on the
Gibbs state of a local\, commuting Hamiltonian. This will allow us to con
clude that any Davies or Schmidt dissipative generator converging to a 2-l
ocal\, commuting Hamiltonian at high-enough temperature thermalises in a t
ime logarithmic in the system size.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/164/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech De Roeck (KU Leuven)
DTSTART:20241203T140000Z
DTEND:20241203T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/166
DESCRIPTION:Title: Absence of Normal Heat Conduction in Strongly Disordered In
teracting Quantum Chains\nby Wojciech De Roeck (KU Leuven) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nWe prove that i
n strongly disordered\, interacting\, quantum chains\, the conductance of
a chain of length L vanishes faster than 1/L. This means that transport is
anomalous in such chains. This phenomenon was first claimed in 2005 in se
minal work by Basko\, Aleiner and Altshuler and a pioneering mathematical
treatment was given by Imbrie in 2014. The proof largely relies on prov
ing a stronger property for some rare intervals on the chain\, whose locat
ion depends on the realization of disorder. This stronger property is cal
led 'Many-Body Localization' and it is of independent interest.\n(joint wo
rk with Lydia Giacomin\, Francois Huveneers\, Oskar Prosniak)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/166/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wendelin Werner (Cambridge)
DTSTART:20250114T140000Z
DTEND:20250114T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/167
DESCRIPTION:Title: Percolation of loops and the Gaussian Free Field\nby We
ndelin Werner (Cambridge) as part of One world IAMP mathematical physics s
eminar\n\n\nAbstract\nThe Gaussian Free Field and its correlation structur
e are\nclosely related to questions about percolation in a gas of independ
ent\nBrownian loops (the loop-soup). We will discuss recent and new result
s\nabout this connection\, and what we can learn about the nature of these
\nunderlying percolation clusters depending on the dimension of space. We\
nwill also mention how this relation can be extended to models for\nlocall
y interacting loops.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Naoto Shiraishi (Tokyo)
DTSTART:20250128T140000Z
DTEND:20250128T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/168
DESCRIPTION:Title: Proving non-integrability of quantum spin systems\nby N
aoto Shiraishi (Tokyo) as part of One world IAMP mathematical physics semi
nar\n\n\nAbstract\nIn mathematical physics\, integrable systems have been
studied intensively\, and various quantum spin models have been revealed t
o be integrable. In contrast\, few studies in mathematical physics have ta
ckled quantum non-integrability. Here we characterize non-integrability by
the absence of local conserved quantity as a working definition. The hard
ness of analyzing non-integrability comes from the fact that there is no g
ood method to treat all possible local conserved quantities. For this reas
on\, non-integrability is sometimes even considered to be out of the scope
of rigorous mathematical physics.\n\nContrary to this pessimistic view\,
a method to prove quantum non-integrability was recently discovered. In th
is seminar\, I will talk about the recent progress in proving non-integrab
ility of quantum spin systems. In the first part\, I will provide the proo
f of non-integrability of S=1/2 XYZ chain with z magnetic field\, where th
e basic proof ideas and techniques can be seen. In the second part\, I wil
l prove the classification of integrability/non-integrability for all S=1/
2 spin chains with symmetric nearest-neighbor interaction. This classifica
tion theorem confirms that there is no missing integrable models in this c
lass. My talk is based on a series of papers including collaborated works
with M. Yamaguchi and Y. Chiba.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/168/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Annalisa Panati (Toulon)
DTSTART:20250211T140000Z
DTEND:20250211T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/169
DESCRIPTION:Title: Entropic fluctuations in quantum two-time measurement frame
work\nby Annalisa Panati (Toulon) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nNon-equilibrium statistical mechanics ha
s seen some impressive developments in the last three decades\, since the
ground-breaking formulation of the transient and steady entropic Fluctuati
on Relations (FR) in the early nineties.\n\nThe extension of these results
to the quantum setting has turned out to be surprisingly challenging and
it is still an ongoing effort. Kurchan and Hal Tasaki's seminal works (200
0) showed quantum formulation of the transient version of FR is possible b
y introducing the two-time measurement framework.\n\nIn this talk\, we pre
sent some results in a recent series of papers\, where we attempt to intro
duce a quantum equivalent of steady entropic functional and compare it to
the transient version for open quantum system.\n\nWe consider both the cas
e of idealised direct measurement on the reservoirs and experimentally acc
essible indirect measurement through coupling with an ancilla. We analyse
in particular stability with respect to the initial state.\nIn order to de
al with the thermodynamic limit and to have general results\, we use metho
ds of $C^*$- algebras and modular theory.\n\n(Joint work with T. Benoist\,
L. Bruneau\, V. Jakšić\, C.A. Pillet)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/169/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ko Sanders (FAU Erlangen-Nürnberg)
DTSTART:20250304T140000Z
DTEND:20250304T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/170
DESCRIPTION:Title: Entanglement and separable states in relativistic QFT\n
by Ko Sanders (FAU Erlangen-Nürnberg) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nIn quantum physics\, entanglement is th
e phenomenon of primary interest. It defines the distinction to classical
physics\, allows for remarkable experiments and raises fundamental questio
ns about nature. This is all the more so in relativistic quantum field the
ories (QFTs)\, where the dependence of entanglement on the localisation in
spacetime can be investigated. In particular\, one can consider the space
time dependence of the entanglement entropy\, which measures the amount of
entanglement in a state by comparing it to "nearby" separable states. In
this talk I will start with a review of the history and basics of entangle
ment and I will describe some results concerning the entanglement entropy\
, keepnig the role of spacetime in mind. Then I will focus on free scalar
QFTs as a toy model and present some results on nice separable states that
may be used to estimate the entanglement entropy.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sven Bachmann (UBC)
DTSTART:20250401T140000Z
DTEND:20250401T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/171
DESCRIPTION:Title: Tensor categories and quantization for the quantum Hall eff
ect\nby Sven Bachmann (UBC) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nThe aim of this talk is to show that quantizat
ion of the Hall conductance in the infinite plane geometry follows from th
e finiteness of the number of the superselection sectors of microscopic qu
antum lattice systems. These are equivalence classes of certain representa
tions of the algebra of observables\, which correspond physically to types
of quasi-particle excitations. I will review aspects of this representati
on theory\, show how it is naturally described in terms of a certain categ
ory\, and explain how the Hall conductance appears within this framework.
This is joint work with M. Corbelli\, M. Fraas and Y. Ogata.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/171/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Schiavina (University of Pavia)
DTSTART:20250318T140000Z
DTEND:20250318T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/172
DESCRIPTION:Title: Superselection sectors from Hamiltonian reduction\nby M
ichele Schiavina (University of Pavia) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nI will discuss the Hamiltonian formulat
ion of local field theories on manifolds with corners in the particular\,
yet common\, case in which they admit an equivariant momentum map. In the
presence of corners\, the momentum map naturally splits into a part encod
ing “Cauchy data” or constraints\, and a part encoding the “flux”
across the corner.\n\nThis decomposition plays an important role in the co
nstruction of the reduced phase space\, which is conveniently handled via
symplectic reduction by stages\, adapted for the occasion to local group a
ctions. \n\nThe output of this analysis are natural Poisson structures ass
ociated to corner submanifolds\, leading to the concept of (classical) flu
x superselection sectors as their symplectic leaves\, and providing a road
map to quantum superselection.\n\nThis general approach has modern applica
tions ranging from electrodynamics to gravitation\, where factorisation fo
rmulas akin to the Peter-Weyl theorem and Verlinde formula are expected\,
owing to the (degenerate) Poisson structure on reduced phase spaces.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/172/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Deuchert (Virginia Tech)
DTSTART:20250415T140000Z
DTEND:20250415T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/173
DESCRIPTION:Title: The Gibbs state of the mean-field Bose gas\nby Andreas
Deuchert (Virginia Tech) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nWe consider the homogeneous mean-field Bose gas at te
mperatures proportional to\nthe critical temperature of its Bose-Einstein
condensation phase transition.\nOur main result is a trace-norm approximat
ion of the grand canonical Gibbs\nstate in terms of a reference state\, wh
ich is given by a convex combination of\nproducts of coherent states and G
ibbs states associated with certain\ntemperature-dependent Bogoliubov Hami
ltonians. The convex combination is\nexpressed as an integral over a Gibbs
distribution of a one-mode phi-4-theory\ndescribing the condensate. We in
terpret this result as a justification of\nBogoliubov theory at positive t
emperature. Further results derived from the\nnorm approximation include v
arious limiting distributions for the number of\nparticles in the condensa
te\, as well as precise formulas for the one- and\ntwo-particle density ma
trices of the Gibbs state. Key ingredients of our proof\,\nwhich are of in
dependent interest\, include two novel abstract correlation\ninequalities.
The proof of one of them is based on an application of an\ninfinite-dimen
sional version of Stahl's theorem.\n
\nThis is joint work with Phan Th
ành Nam and Marcin Napiórkowski\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zaher Hani (Michigan)
DTSTART:20250527T140000Z
DTEND:20250527T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/174
DESCRIPTION:by Zaher Hani (Michigan) as part of One world IAMP mathematica
l physics seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/174/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carolyn Zhang (Harvard)
DTSTART:20250624T140000Z
DTEND:20250624T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/175
DESCRIPTION:Title: Anomaly-free symmetries with obstructions to gauging and on
siteability\nby Carolyn Zhang (Harvard) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nDespite the long history of the st
udy of 't Hooft anomalies and their broad applications\, there is still a
lack of consensus on the precise definition of 't Hooft anomalies. Two com
mon definitions are 1) obstructions to gauging a symmetry and 2) obstructi
ons to a trivially symmetric state. It is often believed that these two de
finitions are equivalent\, and indeed they were recently proven to be equi
valent in 1+1D spin chains with finite\, internal\, unitary symmetries. We
show that this is not the case in 2+1D. In particular\, we present an in
dex $\\omega\\in H^2(G\,Q^{\\times})$ for 0-form finite\, internal\, unita
ry symmetries where $Q^{\\times}$ is the group of rational numbers under m
ultiplication. We show that symmetries with nontrivial $\\omega$ cannot be
gauged or made on-site\, but nevertheless admit trivially symmetric produ
ct states with symmetric commuting parent Hamiltonians.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/175/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Fresta (Bonn)
DTSTART:20250708T140000Z
DTEND:20250708T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/176
DESCRIPTION:Title: Local Dynamics of Extended Fermi Gases at High Density\
nby Luca Fresta (Bonn) as part of One world IAMP mathematical physics semi
nar\n\n\nAbstract\nIn this talk\, I will discuss the quantum evolution of
extended many-body\npseudo-relativistic Fermi gases in a high-density\, se
miclassical scaling\nregime. I will present a result that establishes conv
ergence to the Hartree\ndynamics in the sense of expectation values of loc
al observables\, with a\nconvergence rate depending only on the density. T
he result applies to\ninitial data describing equilibrium states confined
in arbitrarily large\ndomains\, under the assumption of suitable local Wey
l-type estimates. The\nproof is based on approximating the initial data by
low-temperature\nquasi-free states\, for which one can establish a strong
local semiclassical\nstructure\, capturing spatial decay of correlations.
This structure plays a\nkey role in controlling the local growth of fluct
uations under the many-body\ndynamics. Based on joint work with Marcello P
orta (SISSA) and Benjamin\nSchlein (Zürich).\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/176/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Leblé (CNRS)
DTSTART:20250513T140000Z
DTEND:20250513T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/177
DESCRIPTION:Title: Some recent progress on the 2d one-component plasma\nby
Thomas Leblé (CNRS) as part of One world IAMP mathematical physics semin
ar\n\n\nAbstract\nThe two-dimensional one-component “plasma” or “Cou
lomb gas” is an\nimportant model of statistical physics\, which has a cl
ose connection\nwith eigenvalues of random matrices\, with zeroes of Gauss
ian analytic\nfunctions\, and with determinantal point processes.\nI will
give an overview of some recent results showing a strong form of\n“order
” among this system at all temperatures: hyperuniformity\,\nnumber-rigid
ity\, translation-invariance… some of which were predicted\nlong ago in
the physics literature.\nFiguring out its phase portrait remains nonethele
ss an open question\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/177/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Morris Brooks (Zürich)
DTSTART:20251209T140000Z
DTEND:20251209T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/178
DESCRIPTION:Title: The effective mass of the Fröhlich polaron at strong coupl
ing\nby Morris Brooks (Zürich) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nQuantum reference frames allow for the imp
osition of symmetry principles whilst treating all systems quantum mechani
cally. I'll introduce one recent approach to the subject---the operational
approach\, and describe the motivation\, the framework\, some examples an
d main results. I'll then indicate how the introduction of a quantum refer
ence frame for a quantum field theory on background with certain symmetrie
s reduces the type of the von Neumann algebra describing the theory\, rais
ing the possibility of computing physically interesting quantities that ar
e unavailable in standard (algebraic) quantum field theories. I'll conclud
e with some open directions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/178/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Junk (Gakushuin)
DTSTART:20251111T140000Z
DTEND:20251111T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/180
DESCRIPTION:Title: The phase transition for the directed polymer model in high
er dimensions\nby Stefan Junk (Gakushuin) as part of One world IAMP ma
thematical physics seminar\n\n\nAbstract\nThe directed polymer model (or d
irected polymer in a random environment) is a fundamental model for a rand
om walk (polymer) influenced by i.i.d. space-time disorder. The model was
first introduced as an approximation for interfaces of the Ising model but
has recently drawn intensive study due to its connection to the Kardar-Pa
risi-Zhang (KPZ) universality class. It exhibits a rich structure and inte
resting phenomena still only partly understood. In spatial dimension d=1\,
the picture is by now relatively clear by making use of integrable models
\, and recent breakthroughs have expanded our understanding of the case d=
2 as well. \n\nThis talk will focus on recent progress in higher spatial d
imensions (d>2)\, where our understanding remains much more limited. Here\
, the model is known to undergo a phase transition from high temperature (
weak disorder phase)\, where the polymer converges to Brownian motion unde
r diffusive rescaling\, to low temperature (strong disorder phase)\, where
the polymer localizes in small\, favorable corridors in the environment.
Specifically\, I will present our recent result that shows the equivalence
of two different notions of strong disorder and resolves the behavior at
criticality. Based on joint work with Hubert Lacoin.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/180/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Spiegel (UC Davis)
DTSTART:20251014T140000Z
DTEND:20251014T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/181
DESCRIPTION:Title: A Classifying Space for Phases of Matrix Product States
\nby Daniel Spiegel (UC Davis) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nAlexei Kitaev has conjectured that there should
be a loop spectrum consisting of spaces of gapped invertible quantum spin
systems\, indexed by spatial dimension d of the lattice. Motivated by Kit
aev’s conjecture\, I will detail a concrete construction of a topologica
l space B that plays the role of Kitaev’s space in d = 1\, specifically
for translation invariant injective matrix product states (MPS). Having su
ch a space is a useful tool in the discussion of parametrized phases of MP
S\; in fact it allows us to define a parametrized phase as a homotopy clas
s of maps into B. The space B is constructed as the quotient of a contract
ible space E of MPS tensors modulo gauge transformations. The projection m
ap from E to B is a quasifibration\, from which we can compute the homotop
y groups of the classifying space B by a long exact sequence. In particula
r\, B has the weak homotopy type K(Z\, 2) x K(Z\, 3)\, shedding light on K
itaev’s conjecture in the context of MPS.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/181/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leon Loveridge (University of South-Eastern Norway)
DTSTART:20251125T140000Z
DTEND:20251125T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/182
DESCRIPTION:Title: An invitation to Operational Quantum Reference Frames\n
by Leon Loveridge (University of South-Eastern Norway) as part of One worl
d IAMP mathematical physics seminar\n\n\nAbstract\nQuantum reference frame
s allow for the imposition of symmetry principles whilst treating all syst
ems quantum mechanically. I'll introduce one recent approach to the subjec
t---the operational approach\, and describe the motivation\, the framework
\, some examples and main results. I'll then indicate how the introduction
of a quantum reference frame for a quantum field theory on background wit
h certain symmetries reduces the type of the von Neumann algebra describin
g the theory\, raising the possibility of computing physically interesting
quantities that are unavailable in standard (algebraic) quantum field the
ories. I'll conclude with some open directions.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/182/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeffrey Schenker (Michigan State University)
DTSTART:20251028T140000Z
DTEND:20251028T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/183
DESCRIPTION:Title: Finitely Correlated States for Disordered Systems: theory\,
an example\, and open problems\nby Jeffrey Schenker (Michigan State U
niversity) as part of One world IAMP mathematical physics seminar\n\n\nAbs
tract\nMatrix Product States (MPS)\, and more generally Finitely Correlate
d States (FCS)\, have played an important role in the analysis of ground s
tates of spin chains for almost four decades\, beginning with the introduc
tion of the AKLT model and the construction of its ground state by Afleck\
, Kennedy\, Lieb\, and Tasaki in 1987. The general theory of translation
invariant FCS in the thermodynamic limit was developed in a paper by Fanne
s\, Nachtergaele\, and Werner from 1992. In this talk\, I will present re
cent work developing a theory of disordered FCS whose statistical distribu
tion is translation invariant\, as one would expect for a system with homo
geneous spatial disorder. We will consider a disordered generalization of
the AKLT state with interesting properties: the state has exponential clus
tering\, is inherently gapless\, in that it cannot be the ground state of
any gapped local Hamiltonian\, and Tasaki's index for the state can be sho
wn to equal -1\, indicating that it is\, in some sense\, "topologically pr
otected." Finally\, several open problems regarding disordered FCS will be
presented. (Joint work with Eric Roon)\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/183/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Bols (ETH Zürich)
DTSTART:20260106T140000Z
DTEND:20260106T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/184
DESCRIPTION:Title: Anyons in Quantum Spin Systems: Superselection Sectors and
How to Compute Them\nby Alex Bols (ETH Zürich) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nThe theory of superselecti
on sectors\, first developed in algebraic quantum field theory and more re
cently adapted to quantum spin systems by Naaijkens and Ogata\, provides a
rigorous description of the anyonic excitations hosted by gapped ground s
tates of (2+1)-dimensional quantum systems. After a brief introduction to
the general framework\, I will sketch how the sector theory can be compute
d explicitly in a class of exactly solvable models.\nThe talk is based on
joint work with Mahdie Hamdan\, Boris Kjær\, Pieter Naaijkens\, and Sidda
rth Vadnerkar : arXiv:2310.19661\, arXiv:2503.15611\, arXiv:2511.21521\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/184/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Holger Gies (Friedrich Schiller University Jena)
DTSTART:20260120T140000Z
DTEND:20260120T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/185
DESCRIPTION:Title: Quantum field theories of relativistic Luttinger fermions\nby Holger Gies (Friedrich Schiller University Jena) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nWe propose relativisti
c Luttinger fermions as a new ingredient for\nthe construction of fundamen
tal quantum field theories. The resulting fermion\nfields exhibit a canoni
cal scaling different from Dirac fermions and thus\nsupport the constructi
on of novel relativistic and perturbatively\nrenormalizable\, interacting
quantum field theories in four spacetime\ndimensions. In particular\, new
asymptotically free self-interacting field\ntheories can be identified\, r
epresenting first examples of high-energy complete\nquantum field theories
based on purely fermionic matter degrees of freedom. As\nexamples\, we di
scuss models which undergo dimensional transmutation and low-\nenergy cond
ensate formation with scalar excitations on top of the condensate.\nWe obs
erve that a corresponding Yukawa model exhibits features similar to\nself-
organized criticality with a natural separation of low-energy observables\
nfrom high energy initial scales without the need for any fine-tuning. We
also\ncritically examine the analytic structure of the Luttinger-fermionic
\npropagator in the various gapped phases and discuss possible consequence
s for\nasymptotic states.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/185/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Corwin (Columbia)
DTSTART:20260203T140000Z
DTEND:20260203T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/186
DESCRIPTION:Title: Extreme Diffusion\nby Ivan Corwin (Columbia) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nTwo hundred ye
ars ago\, Robert Brown observed the statistics of the motion of grains of
pollen in water. It took almost one hundred years for Einstein and others
to develop an effective theory describing this motion as that of a random
walker. In this talk\, I will challenge a key implication of this well est
ablished theory. When studying systems with very large numbers of particle
s diffusing together\, I will argue that the Einstein random walk theory b
reaks down when it comes to predicting the statistical behavior of extreme
particles—those that move the fastest and furthest in the system. In it
s place\, I will describe a new theory of extreme diffusion which captures
the effect of the hidden environment in which particles diffuse together
and allows us to interrogate that environment by studying extreme particle
s. I will highlight one piece of mathematics that led us to develop this t
heory—a non-commutative binomial theorem—and hint at other connections
to integrable probability\, quantum integrable systems and stochastic PDE
.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/186/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Pérez García (UCM\, Madrid)
DTSTART:20260303T140000Z
DTEND:20260303T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/187
DESCRIPTION:Title: Haag Duality for 2D Quantum Spin Systems\nby David Pér
ez García (UCM\, Madrid) as part of One world IAMP mathematical physics s
eminar\n\n\nAbstract\nHaag duality is a fundamental locality property intr
oduced in the pioneering formulation of algebraic quantum field theory by
Haag and Kastler in the 1960s. Since then\, it has played a central role\,
most notably in the classification of superselection sectors by Doplicher
\, Haag\, and Roberts in the 1970s. Over the past two decades\, this conce
pt has migrated from its relativistic origins to quantum spin systems\, be
coming a cornerstone of the operator-algebraic approach to the long-standi
ng problem of classifying two-dimensional topological quantum phases of ma
tter. However\, rigorous proofs of Haag duality in two dimensions were pre
viously restricted to systems exhibiting abelian anyons. In this talk\, we
will establish Haag duality for a broad class of tensor network models\,
expected to include representatives of all non-chiral topological quantum
phases of matter.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/187/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Gontier (CERMICS\, Ecole Nationale des Ponts et Chaussées\,
France)
DTSTART:20260217T140000Z
DTEND:20260217T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/188
DESCRIPTION:Title: Keller estimates of the eigenvalues in the gap of Dirac ope
rators\nby David Gontier (CERMICS\, Ecole Nationale des Ponts et Chaus
sées\, France) as part of One world IAMP mathematical physics seminar\n\n
\nAbstract\nThe Keller inequality is the Lp version of the well-known Lord
Rayleygh problem: "What shape of drum produces the lowest note?”\, but
this time\, the drum is a potential with fixed Lp norm. In the usual Schr
ödinger case\, was solved by Faber and Krahn around 1920\, and turns out
to be equivalent to the Gagliardo-Niremberg inequality. However\, the usua
l techniques do not apply to the Dirac case. \nIn this talk\, I will provi
de a novel technique which allows to tackle the problem both for Schrödin
ger and Dirac operators\, and which provides interesting numerical schemes
for this optimization problem. I will mention several open problems relat
ed to the Dirac case.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/188/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcos Marino (Geneva)
DTSTART:20260428T140000Z
DTEND:20260428T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/189
DESCRIPTION:by Marcos Marino (Geneva) as part of One world IAMP mathematic
al physics seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/189/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Hinrichs (Paderborn)
DTSTART:20260317T140000Z
DTEND:20260317T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/190
DESCRIPTION:Title: Wavefunction Renormalization of Linear Field-Matter Interac
tions\nby Benjamin Hinrichs (Paderborn) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nLinear interactions between a quan
tum field and non-relativistic matter appear in various mathematical and p
hysical frameworks\, ranging from quantum optics and open quantum systems
over effective models for impurity-environment interactions to toy models
of quantum field theory. In most applications\, the models suffer from bot
h infrared and ultraviolet singularities\, thus necessitating the need for
renormalization. Whereas in some cases a so-called self-energy renormaliz
ation suffices\, which can be carried out in the Hamiltonian formalism\, m
ore singular interactions require a wavefunction renormalization\, which r
esembles the fact that the interacting vacuum is disjoint from the bare on
e.\n\nIn this talk\, we first recall several relevant models and therein d
iscuss the implications of infrared and ultraviolet singularities. We then
introduce a Hamiltonian-based wavefunction renormalization scheme and dis
cuss how it overcomes both the infrared and the ultraviolet problem in the
se models. The talk is based on joint work with Marco Falconi and Javier V
alentín Martín.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/190/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Rademacher (University of Mannheim)
DTSTART:20260512T140000Z
DTEND:20260512T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/191
DESCRIPTION:Title: Long-time validity of Bogoliubov theory\nby Simone Rade
macher (University of Mannheim) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nWe consider the Bogoliubov approximation for t
he many-body quantum dynamics of weakly interacting Bose gases and establi
sh a uniform-in-time validity of Bogoliubov theory. The proof relies on a
detailed analysis of the dispersive behavior of the symplectic Bogoliubov
dynamics\, which allows for a rigorous derivation of the Bogoliubov theory
as an effective description of quantum fluctuations around the Bose-Einst
ein condensate on all time scales. This is joint work with Phan Thanh Nam
and Avy Soffer.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/191/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomotaka Kuwahara (RIKEN)
DTSTART:20260331T140000Z
DTEND:20260331T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/192
DESCRIPTION:Title: Entanglement Hamiltonian on subsystem at non-zero temperatu
res\nby Tomotaka Kuwahara (RIKEN) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nThe entanglement Hamiltonian is an effec
tive Hamiltonian that describes the properties of a subsystem after taking
the partial trace over the rest of the system. It plays a crucial role in
various areas\, including clustering of conditional mutual information\,
Hamiltonian learning\, and quantum algorithms\, etc [1]. However\, determi
ning the structure of the entanglement Hamiltonian is generally a challeng
ing problem. Even at sufficiently high temperatures\, the standard cluster
expansion method is indicated to be ineffective [2].\n\nIn this talk\, I
will present an alternative approach to studying the entanglement Hamilton
ian that works across all temperature regimes. I will also discuss the lim
itations of this method and its implications for further research.\n\n[1]
Tomotaka Kuwahara\, Clustering of Conditional Mutual Information and Quant
um Markov Structure at Arbitrary Temperatures\, Physical Review X 15\, 041
010 (2025)\n\n[2] Kohtaro Kato\, Tomotaka Kuwahara\, Clustering of Conditi
onal Mutual Information via Quantum Belief-Propagation Channels\, arXiv:25
04.02235v2\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/192/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Piet Lammers (CNRS\, Sorbonne Université\, LPSM)
DTSTART:20260414T140000Z
DTEND:20260414T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/193
DESCRIPTION:Title: Gaussian free field convergence of the six-vertex model wit
h Delta between -1 and -1/2\nby Piet Lammers (CNRS\, Sorbonne Universi
té\, LPSM) as part of One world IAMP mathematical physics seminar\n\n\nAb
stract\nIn recent joint work with H. Duminil-Copin\, K. Kozlowski\, and I.
Manolescu\, we proved convergence of the full-plane six-vertex model towa
rds the Gaussian free field\, with an explicit scaling constant. The proof
involves both techniques from non-integrable systems (percolation theory\
, reflection positivity) and integrable systems (Yang-Baxter\, Bethe Ansat
z). The purpose of this talk is to give a high-level overview of the proof
and a glimpse of the ideas involved.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/193/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcin Napiórkowski (University of Warsaw)
DTSTART:20260526T140000Z
DTEND:20260526T150000Z
DTSTAMP:20260404T111411Z
UID:IAMP_seminars/194
DESCRIPTION:Title: The Spin-Wave Approximation in the Quantum Heisenberg Model
\nby Marcin Napiórkowski (University of Warsaw) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nSpin wave theory suggests
that low temperature properties of the Heisenberg model can be described
in terms of noninteracting quasiparticles called magnons. In my talk I wil
l review the basic concepts and predictions of spin wave approximation and
report on recent rigorous results in that direction.\n
LOCATION:https://stable.researchseminars.org/talk/IAMP_seminars/194/
END:VEVENT
END:VCALENDAR