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BEGIN:VEVENT
SUMMARY:Martin Hairer (Imperial College London)
DTSTART:20200505T130000Z
DTEND:20200505T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/1
DESCRIPTION:Title: The Brownian castle\nby Martin Hairer (Imperial College London)
as part of One world IAMP mathematical physics seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Philip Solovej (University of Copenhagen)
DTSTART:20200512T130000Z
DTEND:20200512T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/2
DESCRIPTION:Title: Universality in the structure of atoms and molecules\nby Jan Phi
lip Solovej (University of Copenhagen) as part of One world IAMP mathemati
cal physics seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Clavier (University of Potsdam)
DTSTART:20200519T130000Z
DTEND:20200519T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/3
DESCRIPTION:Title: Borel-Ecalle resummation for a Quantum Field Theory\nby Pierre C
lavier (University of Potsdam) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nBorel-Ecalle resummation of resurgent functions
is a vast generalisation of the well-known Borel-Laplace resummation meth
od. It can be decomposed into three steps: Borel transform\, averaging and
Laplace transform. I will start by a pedagogical introduction of each of
these steps. To illustrate the feasability of the Borel-Ecalle resummation
method I then use it to resum the solution of a (truncated) Schwinger-Dys
on equation of a Wess-Zumino model. This will be done using known results
about this Wess-Zumino model as well as Sauzin's analytical bounds on conv
olution of resurgent functions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sven Bachmann (University of British Columbia)
DTSTART:20200526T130000Z
DTEND:20200526T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/4
DESCRIPTION:Title: Adiabatic quantum transport\nby Sven Bachmann (University of Bri
tish Columbia) as part of One world IAMP mathematical physics seminar\n\n\
nAbstract\nIn the presence of a spectral gap above the ground state energy
\, slowly driven condensed matter systems may exhibit quantized transport
of charge. One of the earliest instances of this fact is the Laughlin argu
ment explaining the integrality of the Hall conductance. In this talk\, I
will discuss transport by adiabatic processes in the presence of interacti
ons between the charge carriers. I will explain the central role played by
the locality of the quantum dynamics in two instances: the adiabatic theo
rem and an index theorem for quantized charge transport. I will also relat
e fractional transport to the anyonic nature of elementary excitations\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihalis Dafermos (Cambridge University)
DTSTART:20200602T130000Z
DTEND:20200602T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/5
DESCRIPTION:Title: The nonlinear stability of the Schwarzschild metric without symmetry
\nby Mihalis Dafermos (Cambridge University) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nI will discuss an upcoming re
sult proving the full finite-codimension non-linear asymptotic stability o
f the Schwarzschild family as solutions to the Einstein vacuum equations i
n the exterior of the black hole region. No symmetry is assumed. The work
is based on our previous understanding of linear stability of Schwarzschil
d in double null gauge. Joint work with G. Holzegel\, I. Rodnianski and M.
Taylor.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Winter (Universitat Autònoma de Barcelona)
DTSTART:20200609T130000Z
DTEND:20200609T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/6
DESCRIPTION:Title: Energy-constrained diamond norms and the continuity of channel capac
ities and of open-system dynamics\nby Andreas Winter (Universitat Aut
ònoma de Barcelona) as part of One world IAMP mathematical physics semina
r\n\n\nAbstract\nThe channels\, and more generally superoperators acting o
n the trace class operators of a quantum system naturally form a Banach sp
ace under the completely bounded trace norm (aka diamond norm). However\,
it is well-known that in infinite dimension\, the norm topology is often "
too strong" for reasonable applications. Here\, we explore a recently intr
oduced energy-constrained diamond norm on superoperators (subject to an en
ergy bound on the input states). Our main motivation is the continuity of
capacities and other entropic quantities of quantum channels\, but we also
present an application to the continuity of one-parameter unitary groups
and certain one-parameter semigroups of quantum channels.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicola Pinamonti (University of Genova)
DTSTART:20200616T130000Z
DTEND:20200616T140000Z
DTSTAMP:20260422T225925Z
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 o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nDuring this t
alk we will review the construction of equilibrium states for interacting\
nscalar quantum field theories\, treated with perturbation theory\, recent
ly proposed by\nFredenhagen and Lindner.\nWe shall in particular see that
this construction is a generalization of known\nresults valid in the case
of C*-dynamical systems. We shall furthermore discuss some properties \nof
these states and we compare them with known results in the physical liter
ature.\nIn the last part of the talk\, we shall show that notions like rel
ative entropy or entropy\nproduction can be given for states which are of
the form discussed in the first part of talk.\nWe shall thus provide an ex
tension to quantum field theory of similar concepts available\nin the case
of C*-dynamical systems.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nilanjana Datta (University of Cambridge)
DTSTART:20200623T130000Z
DTEND:20200623T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/8
DESCRIPTION:Title: Discriminating between unitary quantum processes\nby Nilanjana D
atta (University of Cambridge) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nDiscriminating between unknown objects in a giv
en set is a fundamental task in experimental science. Suppose you are give
n a quantum system which is in one of two given states with equal probabil
ity. Determining the actual state of the system amounts to doing a measure
ment on it which would allow you to discriminate between the two possible
states. It is known that unless the two states are mutually orthogonal\, p
erfect discrimination is possible only if you are given arbitrarily many i
dentical copies of the state.\n\nIn this talk we consider the task of disc
riminating between quantum processes\, instead of quantum states. In parti
cular\, we discriminate between a pair of unitary operators acting on a qu
antum system whose underlying Hilbert space is possibly infinite-dimension
al. We prove that in contrast to state discrimination\, one needs only a f
inite number of copies to discriminate perfectly between the two unitaries
. Furthermore\, no entanglement is needed in the discrimination task. The
measure of discrimination is given in terms of the energy-constrained diam
ond norm and one of the key ingredients of the proof is a generalization o
f the Toeplitz-Hausdorff Theorem in convex analysis. Moreover\, we employ
our results to study a novel type of quantum speed limits which apply to
pairs of quantum evolutions.This work was done jointly with Simon Becker
(Cambridge)\, Ludovico Lami (Ulm) and Cambyse Rouze (Munich)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laure Saint-Raymond (ENS Lyon)
DTSTART:20200630T130000Z
DTEND:20200630T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/9
DESCRIPTION:Title: Fluctuation theory in the Boltzmann-Grad limit\nby Laure Saint-R
aymond (ENS Lyon) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nIn this talk\, I will discuss a long term project with T. Bo
dineau\, I. Gallagher and S. Simonella on hard-sphere dynamics in the kine
tic regime\, away from thermal equilibrium. \n\nIn the low density limit\,
the empirical density obeys a law of large numbers and the dynamics is go
verned by the Boltzmann equation. \n\nDeviations from this behavior are de
scribed by dynamical correlations\, which can be fully characterized for s
hort times. This provides both a fluctuating Boltzmann equation and large
deviation asymptotics.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Despré\;s (Sorbonne University)
DTSTART:20200707T130000Z
DTEND:20200707T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/10
DESCRIPTION:Title: Spectral-scattering theory and fusion plasmas\nby Bruno Despr&e
acute\;s (Sorbonne University) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nMotivated by fusion plasmas and Tokamaks (ITER
project)\, I will describe recent efforts on adapting the mathematical th
eory of linear unbounded self-adjoint operators (Kato\, Lax\, Reed-Simon\,
....) to problems governed by kinetic equations coupled with Maxwell equ
ations.\n\nFirstly it will be shown that Vlasov-Poisson-Ampere equations\,
linearized around non homogeneous Maxwellians\, can be written in the fra
mework of abstract scattering theory (linear Landau damping is a consequen
ce). Secondly the absorption principle applied to the hybrid resonance wil
l be discussed.\n\nAll results come from long term discussions and collabo
rations with many colleagues (Campos-Pinto\, Charles\, Colas\, Heuraux\, I
mbert-Gérard\, Lafitte\, Nicolopoulos\, Rege\, Weder\, and many others).\
n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hal Tasaki (Gakushuin University)
DTSTART:20200714T130000Z
DTEND:20200714T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/11
DESCRIPTION:Title: 'Topological' index and general Lieb-Schultz-Mattis theorems for qu
antum spin chains\nby Hal Tasaki (Gakushuin University) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nA Lieb-Schultz-Mat
tis (LSM) type theorem states that a quantum many-body system with certain
symmetry cannot have a unique ground state accompanied by a nonzero energ
y gap. While the original theorem treats models with continuous U(1) symm
etry\, new LSM-type statements that only assume discrete symmetry have bee
n proposed recently in close connection with topological condensed matter
physics. Here we shall prove such general LSM-type theorems by using the "
topological" index intensively studied in the context of symmetry protecte
d topological phase. Operator algebraic formulation of quantum spin chains
plays an essential role in our approach. Here I do not assume any advance
d knowledge in quantum spin systems or operator algebra\, and illustrate t
he ideas of the proof (which I believe to be interesting).\n
\nThe talk
is based on a joint work with Yoshiko Ogata and Yuji Tachikawa in arXiv:2
004.06458.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolas Rougerie (University of Grenoble Alpes)
DTSTART:20200728T130000Z
DTEND:20200728T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/12
DESCRIPTION:Title: Two modes approximation for bosons in a double well potential\n
by Nicolas Rougerie (University of Grenoble Alpes) as part of One world IA
MP mathematical physics seminar\n\n\nAbstract\nWe study the mean-field lim
it for the ground state of bosonic particles in a double-well potential\,
jointly with the limit of large inter-well separation/large potential ener
gy barrier. Two one-body wave-functions are then macroscopially occupied\,
one for each well. The physics in this two-modes subspace is usually desc
ribed by a Bose-Hubbard Hamiltonian\, yielding in particular the transitio
n from an uncorrelated "superfluid" state (each particle lives in both pot
ential wells) to a correlated "insulating" state (half of the particles li
ve in each potential well). \n\nThrough precise energy expansions we pro
ve that the variance of the number of particles within each well is suppre
ssed (violation of the central limit theorem)\, a signature of a correlate
d ground state. \n\nQuantum fluctuations around the two-modes description
are particularly relevant\, for they give energy contributions of the same
order as the energy difference due to suppressed variances in the two-mod
es subspace. We describe them in terms of two independent Bogoliubov Hamil
tonians\, one for each potential well.\n\nJoint work with Alessandro Olgia
ti and Dominique Spehner\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hugo Duminil-Copin (IHES / University of Geneva)
DTSTART:20200721T130000Z
DTEND:20200721T140000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/13
DESCRIPTION:Title: Marginal triviality of the scaling limits of critical 4D Ising and
&phi\;_4^4 models\nby Hugo Duminil-Copin (IHES / University of Geneva)
as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nIn
this talk\, we will discuss the scaling limits of spin fluctuations in fou
r-dimensional Ising-type models with nearest-neighbor ferromagnetic intera
ction at or near the critical point are Gaussian and its implications from
the point of view of Euclidean Field Theory. Similar statements will be p
roven for the &lambda\;&phi\;4 fields over R^4 with a lattice ultraviolet
cutoff\, in the limit of infinite volume and vanishing lattice spacing. Th
e proofs are enabled by the models' random current representation\, in whi
ch the correlation functions' deviation from Wick's law is expressed in te
rms of intersection probabilities of random currents with sources at dista
nces which are large on the model's lattice scale. Guided by the analogy w
ith random walk intersection amplitudes\, the analysis focuses on the impr
ovement of the so-called tree diagram bound by a logarithmic correction te
rm\, which is derived here through multi-scale analysis.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antti Kupiainen (University of Helsinki)
DTSTART:20200908T140000Z
DTEND:20200908T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/14
DESCRIPTION:Title: Integrability of Liouville Conformal Field Theory\nby Antti Kup
iainen (University of Helsinki) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nA. Polyakov introduced Liouville Conformal Fie
ld theory (LCFT) in 1981 as a way to put a natural measure on the set of R
iemannian metrics over a two dimensional manifold. Ever since\, the work o
f Polyakov has echoed in various branches of physics and mathematics\, ran
ging from string theory to probability theory and geometry. In the context
of 2D quantum gravity models\, Polyakov’s approach is conjecturall
y equivalent to the scaling limit of Random Planar Maps and through the Al
day-Gaiotto- Tachikava correspondence LCFT is conjecturally related to cer
tain 4D Yang-Mills theories. Through the work of Dorn\,Otto\, Zamolodchiko
v and Zamolodchikov and Teschner LCFT is believed to be to a certain exten
t integrable. \n\nI will review a probabilistic construction of LCFT devel
oped together with David\, Rhodes and Vargas and recent proofs concerning
the integrability of LCFT: \n-The proof in a joint work with Rhodes and Va
rgas of the DOZZ formula (Annals of Mathematics\, 81-166\,191 (2020) \n-Th
e proof in a joint work with Guillarmou\, Rhodes and Vargas of the bootstr
ap conjecture for LCFT (arXiv:2005.11530).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Victor Ivrii (University of Toronto)
DTSTART:20200915T140000Z
DTEND:20200915T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/15
DESCRIPTION:Title: Scott and Thomas-Fermi approximations to electronic density\nby
Victor Ivrii (University of Toronto) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nIn heavy atoms and molecules\, on the di
stances $ 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 app
roximated in $L^p$-norm by the ground state electronic density for a singl
e atom in the model with no interactions between electrons.\n\nFurther\, o
n the distances $a \\gg Z^{-1}$ from all of the nuclei (with a charge $Z_1
\,\\ldots\, Z_m$) we prove that $\\rho_\\Psi (x)$ is approximated in $L^p$
-norm\, by the Thomas-Fermi density. We cover both non-relativistic and re
lativistic cases.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Giuliani (University Roma Tre)
DTSTART:20200929T140000Z
DTEND:20200929T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/16
DESCRIPTION:Title: Non-renormalization of the `chiral anomaly' in interacting lattice
Weyl semimetals\nby Alessandro Giuliani (University Roma Tre) as part
of One world IAMP mathematical physics seminar\n\n\nAbstract\nWeyl semimet
als are 3D condensed matter systems characterized by a degenerate Fermi su
rface\, consisting of a pair of `Weyl nodes'. Correspondingly\, in the inf
rared limit\, these systems behave effectively as Weyl fermions in 3+1 dim
ensions. We consider a class of interacting 3D lattice models for Weyl sem
imetals and prove that the quadratic response of the quasi-particle flow b
etween the Weyl nodes\, which is the condensed matter analogue of the chir
al anomaly in QED4\, is universal\, that is\, independent of the interacti
on strength and form. Universality\, which is the counterpart of the Adler
-Bardeen non-renormalization property of the chiral anomaly for the infrar
ed emergent description\, is proved to hold at a non-perturbative level\,
notwithstanding the presence of a lattice\n(in contrast with the original
Adler-Bardeen theorem\, which is perturbative and requires relativistic in
variance to hold). The proof relies on constructive bounds for the Euclide
an ground state correlations combined with lattice Ward Identities\, and i
t is valid arbitrarily close to the critical point where the Weyl points m
erge and the relativistic description breaks down. Joint work with V. Mast
ropietro and M. Porta.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nalini Anantharaman (Strasbourg)
DTSTART:20201103T140000Z
DTEND:20201103T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/17
DESCRIPTION:Title: The bottom of the spectrum of a random hyperbolic surface\nby N
alini Anantharaman (Strasbourg) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nI will report on work in progress with Laura M
onk\, where we study the bottom of the spectrum of the laplacian\, on a co
mpact hyperbolic surface chosen at random\, in the limit of growing genus.
We pick combinatorial ideas from the study of random regular graphs\, to
propose a strategy to prove that\, with high probability\, there are no ei
genvalues below $1/4-\\epsilon$.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Peter Hintz (MIT)
DTSTART:20201110T140000Z
DTEND:20201110T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/18
DESCRIPTION:Title: Linear stability of slowly rotating Kerr spacetimes\nby Peter H
intz (MIT) as part of One world IAMP mathematical physics seminar\n\n\nAbs
tract\nI will describe joint work with Dietrich Häfner and András Vasy i
n which we study the asymptotic behavior of linearized gravitational pertu
rbations of Schwarzschild or slowly rotating Kerr black hole spacetimes. W
e show that solutions of the linearized Einstein equation decay at an inve
rse polynomial rate to a stationary solution (given by an infinitesimal va
riation 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 a
ssociated wave equation on symmetric 2-tensors near zero energy.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Nachtergaele (UC Davis)
DTSTART:20201027T140000Z
DTEND:20201027T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/19
DESCRIPTION:Title: Gapped ground state phases of lattice systems - Stability of the bu
lk gap\nby Bruno Nachtergaele (UC Davis) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nI will give an overview of stabil
ity results for the spectral gap above the ground states of quantum lattic
e systems obtained in the past decade and explain the overall strategy int
roduced by Bravyi\, Hastings\, and Michalakis. A new result I will present
proves the stability of the bulk gap for infinite systems with an approac
h that bypasses possible gapless boundary modes (joint work with Bob Sims
and Amanda Young).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yoshiko Ogata (University of Tokyo)
DTSTART:20201215T140000Z
DTEND:20201215T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/20
DESCRIPTION:Title: Classification of symmetry protected topological phases in quantum
spin systems\nby Yoshiko Ogata (University of Tokyo) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nA Hamiltonian is in a
SPT phase with a given symmetry if it cannot be \nsmoothly deformed into
a trivial Hamiltonian without a phase transition\, \nif the deformation p
reserves the symmetry\,\nwhile it can be smoothly deformed into a trivial
Hamiltonian without a \nphase transition\, if the symmetry is broken durin
g the deformation.\nWe consider this problem for one- and two-dimensional
quantum spin systems with on-site finite \ngroup symmetries.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeremy Quastel (University of Toronto)
DTSTART:20201020T140000Z
DTEND:20201020T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/21
DESCRIPTION:Title: Towards KPZ Universality\nby Jeremy Quastel (University of Toro
nto) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\
nThe 1-d KPZ universality class contains random interface growth models\na
s well as random polymer free energies and driven diffusive systems. \nTh
e KPZ fixed point has now been determined\, through the exact solution of
a special model\nin the class\, TASEP\, and is expected to describe the as
ymptotic fluctuations for all models in the class.\nIt is an integrable Ma
rkov process\, with transition probabilities described by a system of inte
grable PDE's.\n
\nVery recently\, new techniques have become available
to prove \nthe convergence of the KPZ equation itself\, as well as some no
n-integrable extensions\nof TASEP\, to the KPZ fixed point. This talk wil
l be a gentle introduction to these developments\nwith no prior knowledge
assumed. The results are\, variously\, joint works with \nDaniel Remenik\
, Konstantin Matetski\, and Sourav Sarkar.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roland Bauerschmidt (University of Cambridge)
DTSTART:20201124T140000Z
DTEND:20201124T150000Z
DTSTAMP:20260422T225925Z
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 mathemat
ical physics seminar\n\n\nAbstract\nTwo-dimensional statistical and quantu
m field theories are\nspecial in many ways. One striking instance of this
is the equivalence\nof certain bosonic and fermionic fields\, known as bos
onization. I will\nfirst review this correspondence in the explicit instan
ce of the\nmassless Gaussian free field and massless Euclidean Dirac fermi
ons. I\nwill then present a result that extends this correspondence to the
\nnon-Gaussian `massless' sine-Gordon field on $\\R^2$ at $\\beta=4\\pi$ a
nd\nmassive Dirac fermions. This is an instance of Coleman's prediction th
at\nthe `massless' sine-Gordon model and the massive Thirring model are\ne
quivalent. We use this correspondence to show that correlations of the\n`m
assless' sine-Gordon model decay exponentially for $\\beta=4\\pi$.\nThis i
s joint work with C. Webb (arXiv:2010.07096).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Svitlana Mayboroda (University of Minnesota)
DTSTART:20201013T140000Z
DTEND:20201013T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/23
DESCRIPTION:Title: The landscape law for the integrated density of states\nby Svit
lana Mayboroda (University of Minnesota) as part of One world IAMP mathema
tical physics seminar\n\n\nAbstract\nComplexity of the geometry\, randomne
ss of the potential\, and many other irregularities of the system can caus
e powerful\, albeit quite different\, manifestations of localization\, a p
henomenon of sudden confinement of waves\, or eigenfunctions\, to a small
portion of the original domain. In the present talk we show that behind a
possibly disordered system there exists a structure\, referred to as a lan
dscape function\, which can predict the location and shape of the localize
d eigenfunctions\, a pattern of their exponential decay\, and deliver accu
rate bounds for the corresponding eigenvalues. In particular\, we establis
h the "landscape law"\, the first non-asymptotic estimates from above and
below on the integrated density of states of the Schroedinger operator usi
ng a counting function for the minima of the localization landscape. The r
esults are deterministic\, and rely on a new uncertainty principle. Narrow
ing down to the context of disordered potentials\, we derive the best curr
ently available bounds on the integrated density of states for the Anderso
n model.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Hollands (University of Leipzig)
DTSTART:20201117T140000Z
DTEND:20201117T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/24
DESCRIPTION:Title: (In)determinism Inside Black Holes\nby Stefan Hollands (Univers
ity of Leipzig) as part of One world IAMP mathematical physics seminar\n\n
\nAbstract\nIn classical General Relativity\, the values of fields on spac
etime are\nuniquely determined by their initial values within its "domain
of\ndependence". However\, it may occur that the\nspacetime under consider
ation extends beyond this domain\, and\nfields\, therefore\, are not entir
ely determined by their initial data. In fact\, such a naive\nfailure of d
eterminism occurs inside all physically relevant black holes.\n\nThe bound
ary of the region determined by the initial data is\ncalled the "Cauchy ho
rizon". Penrose has proposed ("strong cosmic censorship conjecture")\nthat
the Cauchy horizon is actually unstable in the sense that the slightest p
erturbation caused\nby remnant fields convert it to a final singularity. W
hether or not this is the case --\nand thus whether there is a real proble
m with determinism -- has been put into question recently.\n\nIn this coll
oquium I ask wheter quantum effects will come to the rescue of strong cosm
ic censorship.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ian Jauslin (Princeton University)
DTSTART:20200922T140000Z
DTEND:20200922T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/25
DESCRIPTION:Title: An effective equation to study Bose gasses at both low and high den
sities\nby Ian Jauslin (Princeton University) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nI will discuss an effective
equation\, which is used to study the ground state\n of the interacting Bo
se gas. The interactions induce many-body correlations\n in the system\, w
hich makes it very difficult to study\, be it analytically or\n numericall
y. A very successful approach to solving this problem is Bogolubov\n theor
y\, in which a series of approximations are made\, after which the\n analy
sis reduces to a one-particle problem\, which incorporates the many-body\n
correlations. The effective equation I will discuss is arrived at by maki
ng a\n very different set of approximations\, and\, like Bogolubov theory\
, ultimately\n reduces to a one-particle problem. But\, whereas Bogolubov
theory is accurate\n only for very small densities\, the effective equatio
n coincides with the\n many-body Bose gas at both low and at high densitie
s.\n\n I will show some\n theorems which make this statement more precise\
, and present numerical\n evidence that this effective equation is remarka
bly accurate for all\n densities\, small\, intermediate\, and large. That
is\, the analytical and\n numerical evidence suggest that this effective e
quation can capture many-body\n correlations in a one-particle picture bey
ond what Bogolubov can accomplish.\n Thus\, this effective equation gives
an alternative approach to study the low\n density behavior of the Bose ga
s (about which there still are many important\n open questions). In additi
on\, it opens an avenue to understand the physics of\n the Bose gas at int
ermediate densities\, which\, until now\, were only\n accessible to Monte
Carlo simulations.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Pizzo (University of Rome Tor Vergata)
DTSTART:20201201T140000Z
DTEND:20201201T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/26
DESCRIPTION:Title: Stability of gapped quantum chains under small perturbations\nb
y Alessandro Pizzo (University of Rome Tor Vergata) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nWe consider a family of qu
antum chains that has attracted much interest amongst people studying topo
logical phases of matter. Their Hamiltonians are perturbations\, by intera
ctions of short range\, of a Hamiltonian consisting of on-site terms and w
ith a strictly positive energy gap above its ground-state energy. For inte
ractions that are form-bounded w.r.t. the on-site Hamiltonian terms\, we
prove that the spectral gap of the perturbed Hamiltonian above its ground-
state energy is bounded from below by a positive constant uniformly in th
e 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 conjugations of
the Hamiltonians associated with connected subsets of the chain\, that ca
n be also applied to complex Hamiltonians obtained by considering complex
values of the coupling constant.\n\nWe can treat fermions and bosons on th
e same footing\, and our technique does not face a large field problem\, e
ven though bosons are involved\, in contrast to most approaches. Furthermo
re the method can be extended to higher spatial dimensions.\n\n(Joint work
with S. Del Vecchio\, J. Fröhlich\, and S. Rossi.)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Katrin Wendland (Albert-Ludwigs-Universität Freiburg)
DTSTART:20201208T140000Z
DTEND:20201208T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/27
DESCRIPTION:Title: On invariants shared by geometry and conformal field theory\nby
Katrin Wendland (Albert-Ludwigs-Universität Freiburg) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nI will recall how some
conformal field theories can be given geometric interpretations. This can
be useful from a practical point of view\, when geometric methods are tra
nsferred from geometry to conformal field theory. I will in particular foc
us on certain invariants that are shared by geometry and conformal field t
heory\, including the complex elliptic genus. As we shall see\, this invar
iant is also useful from a theoretical viewpoint\, since it captures infor
mation about generic properties of certain theories.\n
LOCATION:https://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:20260422T225925Z
UID:IAMP_seminars/28
DESCRIPTION:Title: Nonlinear quantum adiabatic approximation\nby Clotilde Fermania
n-Kammerer (Université\; Paris Est - Cré\;teil Val de Marne) a
s part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe wi
ll discuss generalization of the quantum adiabatic theorem to a nonlinear
setting. We will consider evolution equations where the Hamiltonian operat
or depends on the time variable and on a finite number of parameters that
are fixed on some coordinates of the unknown\, making the equation non-lin
ear. Under natural spectral hypotheses\, there exist special functions tha
t we call « Instantaneous nonlinear eigenvectors » such that\, in the ad
iabatic limit\, the solutions of the nonlinear equations with those initia
l data remain close to them\, up to a rapidly oscillating phase. We will e
xplain why this question arises\, discuss the proof of this result and sho
w how it can fail (works in collaboration with Alain Joye and Rémi Carles
).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabio Toninelli (Technical University Vienna)
DTSTART:20210112T140000Z
DTEND:20210112T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/29
DESCRIPTION:Title: The anisotropic KPZ equation and logarithmic super-diffusivity\
nby Fabio Toninelli (Technical University Vienna) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nThe AKPZ equation is an anis
otropic variant of the celebrated (two-dimensional) KPZ stochastic PDE\, w
hich is expected to describe the large-scale behavior of (2+1)-dimensional
growth models whose average speed of growth is a non-convex function of
the average slope (AKPZ universality class). Several interacting particle
systems belonging to the AKPZ class are known\, notably a class of two-dim
ensional interlaced particle systems introduced by A. Borodin and P. Ferra
ri. In this talk\, I will show that the non-linearity of the AKPZ equation
is marginally relevant in the Renormalization Group sense: in fact\, whil
e the 2d-SHE is invariant under diffusive rescaling\, for AKPZ the diffusi
on coefficient diverges (logarithmically) for large times\, implying margi
nal super-diffusivity. [Based on joint work with G. Cannizzaro and D. Erha
rd]\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Seiringer (IST Austria)
DTSTART:20210119T140000Z
DTEND:20210119T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/30
DESCRIPTION:Title: Quantum fluctuations and dynamics of a strongly coupled polaron
\nby Robert Seiringer (IST Austria) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nWe review old and new results on the Fröh
lich polaron model. The discussion includes the validity of the (classical
) Landau--Pekar equations for the dynamics in the strong coupling limit\,
quantum corrections to this limit\, as well as the divergence of the effec
tive polaron mass.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Margherita Disertori (University of Bonn)
DTSTART:20210302T140000Z
DTEND:20210302T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/31
DESCRIPTION:Title: Supersymmetric transfer operators\nby Margherita Disertori (Uni
versity of Bonn) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nTransfer matrix approach is a powerful tool to study one dime
nsional or quasi 1d statistical mechanical models. Transfer operator kerne
ls arising in the context of quantum diffusion and the supersymmetric ap
proach display bosonic and fermionic components. For such kernels\, the pr
esence of fermion-boson symmetries allows to drastically simplify the prob
lem. 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 Lohmann.
\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Wehr (University of Arizona)
DTSTART:20210330T140000Z
DTEND:20210330T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/32
DESCRIPTION:Title: Aggregation and deaggregation of interacting micro swimmers\nby
Jan Wehr (University of Arizona) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nA swarm of light-sensitive robots is moving
in a planar region\, changing the direction of motion randomly. Each robo
t emits light\; in turn\, it adapts the speed of its motion to the total i
ntensity of the light shed on it by the other robots. The adaptation take
s time---the sensorial delay. Using a natural approximation of the equati
ons of motion\, the robots may be programmed to make the sensorial delay n
egative. In this case they are\, in some sense\, predicting the future.
In a series of experiments by the Giovanni Volpe group and the University
of Gothenburg (Sweden) it was shown that at a certain negative value of th
e delay\, the collective behavior of the robots changes qualitatively from
aggregation to deaggregation. I am going to explain this phenomenon by a
n asymptotic analysis of the system of stochastic differential equations\,
describing the motion of a single robot in an inhomogeneous landscape. \n
\nThe results were obtained in a joint work with Giovanni Volpe\, Mite Mij
alkov and Austin McDaniel. They display an interesting feature: while th
e original system is driven by a single noise source\, the limiting one co
ntains two independent ones. I will explain this by showing how one can g
enerate two independent Wiener processes from a single one. Using this fa
ct to rigorously justify the asymptotic results is a work in progress with
Jeremiah Birrell.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jürg Fröhlich (ETH Zürich)
DTSTART:20210126T140000Z
DTEND:20210126T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/33
DESCRIPTION:Title: The Evolution of States as the Fourth Pillar of Quantum Mechanics\nby Jürg Fröhlich (ETH Zürich) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nI present ideas about how to extend the s
tandard formalism of Quantum\nMechanics in such a way that the theory actu
ally makes sense. My\ntentative extension is called\n\n "ET
H-Approach to Quantum Mechanics"\n\n(for "Events\, Trees and Histories").\
n\nThis approach supplies the last of four pillars QM can be constructed u
pon\,\nwhich are:
\n(i) Physical quantities characteristic of a phys
ical system are represented\n by self-adjoint operators\;
\n(ii) t
he time evolution of these operators is given by the Heisenberg equation\;
\n(iii) meaningful notions of states and of "potential" and "actual ev
ents" have\n to be introduced\; and
\n(iv) a general law for the t
ime evolution of states (superseding Schroedinger\n evolution\, which
is inadequate) must be formulated.\n\nBesides briefly sketching the ETH-Ap
proach 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 l
imit where the speed of light tends to infinity\,\nAn analysis of these mo
dels\, which illustrate the ETH Approach\, is the main\nsubject of the tal
k.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tyler Helmuth (University of Durham)
DTSTART:20210223T140000Z
DTEND:20210223T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/34
DESCRIPTION:Title: Efficient algorithms for low-temperature spin systems\nby Tyler
Helmuth (University of Durham) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nTwo fundamental algorithmic tasks associated t
o discrete statistical mechanics models are approximate counting and appro
ximate sampling. At high temperatures Markov chains give efficient algorit
hms\, but at low temperatures mixing times can become impractically large\
, and Markov chain methods may fail to be efficient. Recently\, expansion
methods (cluster expansions\, Pirogov--Sinai theory) have been put to use
to develop provably efficient low-temperature algorithms for some discrete
statistical mechanics models. I’ll introduce these algorithmic tasks\,
outline how expansion algorithms work\, and indicate some open directions.
\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sylvia Serfaty (Courant Institute)
DTSTART:20210323T140000Z
DTEND:20210323T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/35
DESCRIPTION:Title: Ginzburg-Landau vortices\, old and new\nby Sylvia Serfaty (Cour
ant Institute) as part of One world IAMP mathematical physics seminar\n\n\
nAbstract\nWe present a review of results on vortices in the 2D Ginzburg-L
andau model of superconductivity (also relevant for superfluidity and Bose
-Einstein condensates)\, their onset at critical fields\, interaction and
patterns. We also report on recent joint work with Carlos Roman and Etie
nne Sandier in which we study the onset of vortex lines in the 3D model an
d derive an interaction energy for them.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Søren Fournais (Aarhus University)
DTSTART:20210105T140000Z
DTEND:20210105T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/36
DESCRIPTION:Title: The ground state energy of dilute Bose gases\nby Søren Fournai
s (Aarhus University) as part of One world IAMP mathematical physics semin
ar\n\n\nAbstract\nThe rigorous calculation of the ground state energy of d
ilute Bose gases has been a challenging problem since the 1950s. In partic
ular\, it is of interest to understand the extent to which the Bogoliubov
pairing theory correctly describes the ground state of this physical syste
m.\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 term\, a
nd its relation to Bogoliubov theory.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Wu (NYU Shanghai)
DTSTART:20210202T140000Z
DTEND:20210202T150000Z
DTSTAMP:20260422T225925Z
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 seminar\n\n
\nAbstract\nThe XY and the Villain models are mathematical idealization of
real world models of liquid crystal\, liquid helium\, and superconductors
. Their phase transition has important applications in condensed matter ph
ysics and led to the Nobel\nPrize in Physics in 2016. However we are still
far from a complete mathematical\nunderstanding of the transition. The sp
in wave conjecture\, originally proposed by Dyson and by Mermin and Wagner
\, predicts that at low temperature\, large scale behaviors of these model
s are closely related to Gaussian free fields. I will review the historica
l background and discuss some recent progress on this conjecture in $d \\g
eq 3$.\nBased on the joint work with Paul Dario (Tel Aviv).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gianluca Panati (University of Rome Sapienza)
DTSTART:20210316T140000Z
DTEND:20210316T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/38
DESCRIPTION:Title: The Localization Dichotomy in Solid State Physics\nby Gianluca
Panati (University of Rome Sapienza) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nSolid state systems exhibit a subtle inte
rtwining between the topology of the\n"manifold" of occupied states and th
e localization of electrons\, if the latter is appropriately defined. \n\nThis correspondence has been first noticed and proved\nin the case of
periodic gapped systems: for non interacting electrons\,\nlocalizat
ion is measured via the localization of the Composite Wannier Bases (CWBs)
\nspanning the range of the Fermi projector $P_F$\, while the topological
information is encoded \nin the (first) Chern class of the Fermi projecto
r. It has been proved\, for dimension $d \\leq 3$ \nthat only two regimes
are possible:
\ni) either there exists an exponentially localized CWB\
, and correspondingly the Chern \nclass of $P_F$ vanishes (ordinary insula
tor)\;
\nii) or any possible choice of a CWB is delocalized\, i
n the sense that it \nyields an infinite expectation value for the square
of \nthe position operator\, and the Chern class is non zero (Chern insula
tor).\n
\nMore recently\, the previous dichotomy has been reformulated
in such a way that it applies\nalso to non-periodic systems\, and a corres
ponding "Localization Dichotomy conjecture" for\nnon-periodic systems has
been stated. \n
\nIn my talk\, I will gently introduce the subject\, st
arting from the periodic case\, and summarize the \nrecent attempts\, by s
everal groups\, to prove the Localization Dichotomy for non-periodic syste
ms. \n
\nThe talk is based on work in collaboration with D. Monaco\, M.
Marcelli\, M. Moscolari\, \nA. Pisante\, and S. Teufel\, and on discussio
ns with several colleagues.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gerald Dunne (University of Connecticut)
DTSTART:20210216T140000Z
DTEND:20210216T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/39
DESCRIPTION:Title: Resurgent Asymptotics and Non-perturbative Physics\nby Gerald D
unne (University of Connecticut) as part of One world IAMP mathematical ph
ysics seminar\n\n\nAbstract\nThere are several important conceptual and co
mputational questions concerning path integrals\, which have recently been
approached from new perspectives motivated by Ecalle's theory of resurgen
t functions\, a mathematical formalism that unifies perturbative and non-p
erturbative physics. I will review the basic ideas behind the connections
between resurgent asymptotics and physics\, with examples from quantum mec
hanics and matrix models.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Herbert Spohn (TU Munich)
DTSTART:20210209T140000Z
DTEND:20210209T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/40
DESCRIPTION:Title: Generalised hydrodynamics of the Toda lattice\nby Herbert Spohn
(TU Munich) as part of One world IAMP mathematical physics seminar\n\nAbs
tract: TBA\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Warzel (TU Munich)
DTSTART:20210309T140000Z
DTEND:20210309T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/41
DESCRIPTION:Title: An invitation to quantum spin glasses\nby Simone Warzel (TU Mun
ich) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\
nQuantum spin glass models of mean-field type are prototypes of quantum sy
stems exhibiting phase transitions related to the spead of the eigenstates
in configuration space. \nOriginally motivated by spin glass physics\, t
hey are discussed in relation to many-body localisation phenomena\, quantu
m adiabatic algorithms as well as in the context of models in mathematical
biology. \nQuantum effects transform the rich phase diagram of classical
spin glasses as described by Parisi’s theory into an even more colourful
landscape of phases which range from purely quantum paramagnetic to inter
mediate behavior in which eigenstates occupy only a fraction of configurat
ion space.\n\nIn this talk\, I will give an introduction to the multifacet
ed motivations and challenges behind the study of these quantum glasses an
d explain existing and expected results.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech De Roeck (KU Leuven)
DTSTART:20210413T140000Z
DTEND:20210413T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/42
DESCRIPTION:Title: Impurities and boundaries for a class of gapped ground states\n
by Wojciech De Roeck (KU Leuven) as part of One world IAMP mathematical ph
ysics seminar\n\n\nAbstract\nIn the last two decades\, a lot of rigorous r
esults have been proven for quantum ground states protected by a spectral
gap in their Hamiltonian. Think for example of decay of correlations\, the
topological classification of states\, and area laws of entanglement.\nFo
r all of those results\, the spectral gap is a necessary input\, both on t
he conceptual and on the technical level. \nImagine now that we consider s
uch a gapped Hamiltonian that is perturbed locally by a term that is not s
mall\, such that we certainly cannot hope to preserve the global gap. Comm
on sense dictates that\, far away from the perturbation\, the ground 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 describe
some results that go in this direction.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Carlen (Rutgers University)
DTSTART:20210420T140000Z
DTEND:20210420T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/43
DESCRIPTION:Title: Kac Master Equations\, Classical and Quantum\nby Eric Carlen (R
utgers University) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nThis lecture will review recent progress and open problems
concerning Kac Master Equations in both the classical and quantum setting.
It will be based largely on recent papers written in collaboration with M
aria Carvalho\, Michael Loss and Bernt Wennberg.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bernard Helffer (Paris-Sud / Nantes)
DTSTART:20210406T140000Z
DTEND:20210406T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/44
DESCRIPTION:Title: Semiclassical methods and tunneling effects: old and new\nby Be
rnard Helffer (Paris-Sud / Nantes) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nIn 1982-1983 the so-called symmetric doubl
e well problem was rigorously analyzed in any dimension in the semi-classi
cal context by B. Simon and Helffer-Sjöstrand.\nThis involves semi-clas
sical Agmon estimates\, Harmonic approximation\, WKB constructions and a v
ery fine analysis of the so-called tunneling effect in order to establish
the splitting between the lowest eigenvalues.\n\nThe strategy followed by
Helffer-Sjöstrand appears to be quite efficient in many other contexts.
After recalling how it works on the initial double well problem\,\nwe will
discuss in a rather impressionist way the main successes of the approach
along the years.\nFinally we will focus on a quite recent result by Bonna
illie-Hérau-Raymond devoted to the measure of a magnetic tunneling in Sur
face Superconductivity and discuss open problems.\n\nThe presented results
correspond to contributions by various subsets of the following set of au
thors : Bonnaillie\, Fournais\, Helffer\, Hérau\, Kachmar\, Morame\, Nier
\,\nRaymond\, Simon\, Sjöstrand and many others...\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sabine Jansen (LMU Munich)
DTSTART:20210427T140000Z
DTEND:20210427T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/45
DESCRIPTION:Title: Virial expansion for mixtures: some examples & recent results\n
by Sabine Jansen (LMU Munich) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nMayer's expansion is an expansion of the pressur
e in powers of the activity (fugacity) in equilibrium statistical mechanic
s\; the virial expansion is an expansion in powers of the density. Rigorou
s convergence results have been available for decades\, nevertheless for m
ixtures the theory of density expansions is less advanced than the theory
of activity expansions. I will review the setting\, and discuss some recen
t results for the virial expansion for mixtures (multi-species systems) an
d illustrate them with three concrete models: mixtures of hard spheres of
different sizes\, non-overlapping rods of different lengths\, and a hierar
chical mixture of cubes in $Z^d$. The last two examples are helpful toy mo
dels for which concrete formulas are available and phase transitions can b
e studied. Based in part on joint works with Tobias Kuna\, Stephen Tate\,
Dimitrios Tsagkarogiannis and Daniel Ueltschi.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Brydges (University of British Columbia)
DTSTART:20210511T140000Z
DTEND:20210511T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/46
DESCRIPTION:Title: Lace expansions and spin models\nby David Brydges (University o
f British Columbia) as part of One world IAMP mathematical physics seminar
\n\n\nAbstract\nI will review lace expansions starting with their\nrelatio
n to the other expansions in statistical mechanics and then\ndiscussing th
eir application to spin models. Akira Sakai opened\nthis avenue in 2007 wi
th his proof that in sufficiently high dimension\n$d$ the two point functi
on for the critical Ising model is asymptotic\nto $c_d |x-y|^{-(d-2)}$. I
n arxiv.org/abs/1905.09605
Tyler\nHelmuth\, Mark Holmes and I have introduced a different way to deri
ve\nlace expansions based on the Symanzik random walk representation.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcel Griesemer (University of Stuttgart)
DTSTART:20210518T140000Z
DTEND:20210518T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/47
DESCRIPTION:Title: From Short-Range to Contact Interactions in Many-Body Quantum Syste
ms\nby Marcel Griesemer (University of Stuttgart) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nMany-body quantum system
s with short-ranged two-body interactions\, such as ultracold quantum gase
s are often described by simplified models with contact interactions (some
times called delta-potentials). The merit of such models is their simplici
ty\, solvability (to some extent) and lack of irrelevant or unknown detail
. They are also toy models of renormalization. On the other hand\, in dime
nsions $d\\geq 2$ 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 intera
ctions and their approximation by Schrödinger operators.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constanza Rojas-Molina (Cergy Paris University)
DTSTART:20210525T140000Z
DTEND:20210525T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/48
DESCRIPTION:Title: Fractional random Schrödinger operators\, integrated density of st
ates and localization\nby Constanza Rojas-Molina (Cergy Paris Universi
ty) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\n
We will review some recent results on the fractional Anderson model\, a ra
ndom Schrödinger operator driven by a fractional laplacian. The interest
of the latter lies in its association to stable Levy processes\, random wa
lks with long jumps and anomalous diffusion. We discuss the interplay betw
een the non-locality of the fractional laplacian and the localization prop
erties of the random potential in the fractional Anderson model\, in both
the continuous and discrete settings. In the discrete setting we study the
integrated density of states and show a fractional version of Lifshitz ta
ils. This coincides with results obtained in the continuous setting by the
probability community. This talk is based on joint work with M. Gebert (L
MU Munich).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Fewster (University of York)
DTSTART:20210504T140000Z
DTEND:20210504T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/49
DESCRIPTION:Title: Measurement of quantum fields in curved spacetimes\nby Chris Fe
wster (University of York) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nA standard account of the measurement chain in quan
tum mechanics involves a probe (itself a quantum system) coupled temporari
ly to the system of interest. Once the coupling is removed\, the probe is
measured and the results are interpreted as the measurement of a system ob
servable. Measurement schemes of this type have been studied extensively i
n Quantum Measurement Theory\, but they are rarely discussed in the contex
t of quantum fields and still less on curved spacetimes. \n\nIn this talk
I will describe how measurement schemes may be formulated for quantum fiel
ds on curved spacetime within the general setting of algebraic QFT. In par
ticular\, I will show how measurements of probe observables correspond to
measurements of "induced" local system observables and describe the role o
f state update rules. The framework is local and fully covariant\, allowin
g the consistent description of measurements made in spacelike separated r
egions. Furthermore\, specific models can be given in which the framework
may be exemplified by concrete calculations. I will also explain how this
framework can shed light on an old problem due to Sorkin concerning "impos
sible measurements" in which measurement apparently conflicts with causali
ty. Finally\, I will discuss new results indicating that the system observ
ables that can be induced by measurement schemes form a large subspace of
the algebra of all local observables.\n\nThe talk is based on work with Ra
iner Verch [Leipzig]\, (Comm. Math. Phys. 378\, 851–889(2020)\, arXiv:18
10.06512\; see also arXiv:1904.06944 for a summary)\, with Henning Bostelm
ann and Maximilian Ruep [York] ( Phys. Rev. D 103 (2021) 025017\; arXiv:20
03.04660) and work in progress with Ian Jubb [Dublin] and Maximilian Ruep.
\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Schlein (University of Zürich)
DTSTART:20210601T140000Z
DTEND:20210601T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/50
DESCRIPTION:Title: Correlation energy of weakly interacting Fermi gases\nby Benjam
in Schlein (University of Zürich) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nWe consider Fermi gases in a mean-field reg
ime. To leading order\, the ground state energy is given by Hartree-Fock t
heory. The correction to the Hartree-Fock energy\, produced by the many-bo
dy interaction\, is known as correlation energy. In this talk\, we obtain
a formula for the correlation energy\, based on the observation that\, ene
rgetically\, the main excitations of the Fermi sea are particle-hole pairs
that behave\, approximately\, as bosons and can therefore be dealt with t
hrough (bosonic) Bogoliubov theory. The talk is based on joint works with
N. Benedikter\, P.T. Nam\, M. Porta and R. Seiringer.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laszlo Erdös (IST Austria)
DTSTART:20210608T140000Z
DTEND:20210608T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/51
DESCRIPTION:Title: Eigenstate thermalisation hypothesis and Gaussian fluctuations for
Wigner matrices\nby Laszlo Erdös (IST Austria) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nWe prove that any determi
nistic matrix is approximately\nthe identity in the eigenbasis of a large
random Wigner matrix W\nwith an optimal error inversely proportional to th
e square root of the dimension.\nThis verifies a strong form of Quantum U
nique Ergodicity \nwith an optimal convergence rate and we also prove Gaus
sian fluctuations\naround this convergence.\nThe key technical tool is a n
ew multi-resolvent local law for Wigner\nensemble and the Dyson Brownian m
otion for eigenvector overlaps.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gordon Slade (UBC Vancouver)
DTSTART:20210615T140000Z
DTEND:20210615T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/52
DESCRIPTION:Title: Mean-field tricritical polymers\nby Gordon Slade (UBC Vancouver
) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe
provide a full description of a tricritical phase diagram in the setting
of a mean-field random walk model of a polymer density transition. The mod
el involves a continuous-time random walk on the complete graph in the lim
it as the number of vertices N in the graph grows to infinity. The walk ha
s a repulsive self-interaction\, as well as a competing attractive self-in
teraction whose strength is controlled by a parameter g. A chemical potent
ial 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 polyme
r chain. The proof uses a supersymmetric representation for the random wal
k model\, followed by a single block-spin renormalisation group step to re
duce the problem to a 1-dimensional integral\, followed by application of
the Laplace method for an integral with a large parameter. The talk is bas
ed on joint work with Roland Bauerschmidt\, Probability and Mathematical P
hysics 1\, 167-204 (2020)\; arXiv:1911.00395 .\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clément Tauber (University of Strasbourg)
DTSTART:20210622T140000Z
DTEND:20210622T150000Z
DTSTAMP:20260422T225925Z
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 topological
insulators to a fluid dynamics problem: the rotating shallow-water wave m
odel with odd viscosity. The bulk-edge correspondence explains the presenc
e of remarkably stable waves propagating towards the east along the equato
r and observed in some Earth oceanic layers. The odd viscous term is a sma
ll-scale regularization that provides a well defined Chern number for this
continuous model where momentum space is unbounded. Equatorial waves then
appear as interface modes between two hemispheres with a different topolo
gy. However\, in presence of a sharp boundary there is a surprising mismat
ch in the bulk-edge correspondence: the number of edge modes depends on th
e boundary condition. I will explain the origin of such a mismatch using s
cattering theory and Levinson’s theorem. This talk is based on a series
of joint works with Pierre Delplace\, Antoine Venaille\, Gian Michele Graf
and Hansueli Jud.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mathieu Lewin (Paris Dauphine University)
DTSTART:20210629T140000Z
DTEND:20210629T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/54
DESCRIPTION:Title: Density Functional Theory: some recent results\nby Mathieu Lewi
n (Paris Dauphine University) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nThe quantum electrons in an atom or a molecule a
re in principle described by the Schrödinger multi-particle linear equati
on. Unfortunately\, in most cases it is essentially impossible to find a s
ufficiently precise numerical approximation of the solution\, due to the v
ery high dimensionality of the problem. It is absolutely necessary to reso
rt to approximate models\, most of which being nonlinear. Density Function
al Theory (DFT) is probably the most successful and widely used method in
Chemistry and Physics. In this talk I will explain what DFT is and outline
its mathematical formulation. I will then describe some recent results ob
tained in collaboration with Elliott H. Lieb (Princeton) and Robert Seirin
ger (IST Austria).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikolaos Zygouras (University of Warwick)
DTSTART:20210706T140000Z
DTEND:20210706T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/55
DESCRIPTION:Title: On the 2d-KPZ\nby Nikolaos Zygouras (University of Warwick) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe Kar
dar-Parisi-Zhang (KPZ) equation in dimension 1 is by now fairly well under
stood\, both in terms of its solution theory and its phenomenology. But in
the critical dimension 2\, the first steps of progress have only recentl
y been made\, which shows signs of a rich structure. In particular\, a pha
se transition is observed when the noise is suitably scaled. Below the cri
tical scaling\, the 2d KPZ coincides with the Edwards-Wilkinson universali
ty\, while at the critical scaling and beyond\, its behaviour is still mys
terious. We will review joint works with F. Caravenna and R. Sun as well a
s contributions by other groups\, and expose some of the tools used\, incl
uding (discrete) stochastic analysis\, renewal theory\, and mathematical p
hysics ideas from the study of disorder relevance and Schrodinger operator
s with point interactions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Malamud (Peoples Friendship University of Russia\, Moscow)
DTSTART:20210713T140000Z
DTEND:20210713T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/56
DESCRIPTION:Title: On the spectral theory of Schrodinger and Dirac operators with poin
t interactions and quantum graphs\nby Mark Malamud (Peoples Friendship
University of Russia\, Moscow) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nModern concepts of extension theory of symmetr
ic operators\, including concepts of boundary triples\, corresponding Weyl
functions\, and boundary operators will be discussed. Applications to Sch
rodinger and Dirac operators with point interactions\, as well as to quant
um graphs\, will be demonstrated. It turns out that certain spectral prope
rties of each of these operators (deficiency indices\, selfadjointness\, d
iscreteness\, lower semiboundedness\, etc) strictly correlate to that of a
special difference operator. In the first two cases the corresponding dif
ference operator is generated by a special Jacobi matrix. This matrix appe
ars as a boundary operator of the corresponding Schrodinger and Dirac real
ization in an appropriate boundary triple. In the case of quantum graphs a
similar role is played by a certain weighted discrete Laplacian on the un
derlying discrete graph\, which also appears as a boundary operator.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Phan Thành Nam (LMU Munich)
DTSTART:20210720T140000Z
DTEND:20210720T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/57
DESCRIPTION:Title: Bogoliubov excitation spectrum of dilute trapped Bose gases\nby
Phan Thành Nam (LMU Munich) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nIn 1947\, Bogoliubov proposed an approximation f
or the low-lying eigenvalues of weakly interacting Bose gases and used tha
t to explain Landau’s criterion for superfluidity. We will discuss a rig
orous derivation of Bogoliubov’s approximation for a general trapped Bos
e gas in the Gross-Pitaevskii regime\, where the two-body scattering proce
ss of particles leads to an interesting nonlinear effect. The talk is base
d on joint work with Arnaud Triay.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eveliina Peltola (University of Bonn)
DTSTART:20210727T140000Z
DTEND:20210727T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/58
DESCRIPTION:Title: On large deviations of SLEs\, real rational functions\, and zeta-re
gularized determinants of Laplacians\nby Eveliina Peltola (University
of Bonn) as part of One world IAMP mathematical physics seminar\n\n\nAbstr
act\nWhen studying large deviations (LDP) of Schramm-Loewner evolution (SL
E) curves\,\nwe recently introduced a ''Loewner potential'' that describes
the rate function for the LDP.\nThis object turned out to have several in
trinsic\, and perhaps surprising\, connections to various fields.\nFor ins
tance\, it has a simple expression in terms of zeta-regularized determinan
ts of Laplace-Beltrami operators.\nOn the other hand\, minima of the Loewn
er potential solve a nonlinear first order PDE that arises\nin a semiclass
ical limit of certain correlation functions in conformal field theory\,\na
rguably also related to isomonodromic systems.\nFinally\, and perhaps most
interestingly\, the Loewner potential minimizers classify\nrational funct
ions with real critical points\, thereby providing a novel proof for\na ve
rsion of the now well-known Shapiro-Shapiro conjecture in real enumerative
geometry.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antti Knowles (University of Geneva)
DTSTART:20210831T140000Z
DTEND:20210831T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/59
DESCRIPTION:Title: The Euclidean phi^4_2 theory as a limit of an interacting Bose gas<
/a>\nby Antti Knowles (University of Geneva) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nLocal Euclidean field theories ov
er d-dimensional space have been extensively studied in the mathematical l
iterature since the sixties\, motivated by high-energy physics and statist
ical mechanics. For d=2\, I explain how the complex scalar field theory wi
th quartic interaction arises as a limit of an interacting Bose gas at pos
itive temperature\, when the density of the gas becomes large and the rang
e of the interaction becomes small. The proof is based on a quantitative a
nalysis of a new functional integral representation of the interacting Bos
e gas combined with a Nelson-type argument for a general nonlocal field th
eory. Joint work with Jürg Fröhlich\, Benjamin Schlein\, and Vedran Sohi
nger.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Germain (New York University)
DTSTART:20210907T140000Z
DTEND:20210907T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/60
DESCRIPTION:Title: Derivation of the kinetic wave equation\nby Pierre Germain (New
York University) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nThe kinetic wave equation (KWE) is to nonlinear waves what t
he Boltzmann equation is to classical particles. The KWE is also very clos
ely related to quantum versions of the Boltzmann equation. Finally\, the K
WE provides an entrypoint into turbulent phenomena\, since it is aimed at
describing weakly turbulent flows. For all these reasons\, the KWE is an i
nteresting object\, and the question of its validity a fundamental one. I
will review recent progress on this question.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniela Cadamuro (University of Leipzig)
DTSTART:20210810T140000Z
DTEND:20210810T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/61
DESCRIPTION:Title: Operator-algebraic construction of quantum integrable models with b
ound states\nby Daniela Cadamuro (University of Leipzig) as part of On
e world IAMP mathematical physics seminar\n\n\nAbstract\nThe rigorous cons
truction of quantum field theories with self-interaction is one of the lon
gstanding problems of Mathematical Physics. Progress in this respect has b
een made in integrable field theories in 1+1 spacetime dimensions. These a
re characterized by a factorizing scattering matrix\, where two-particle i
nteraction determines scattering completely.\n\nSpecifically\, some of the
se theories (so-called scalar models without bound states) have been succe
ssfully treated in the operator-algebraic approach\, which is based on qua
ntum fields localized in infinitely extended wedge regions. The existence
of strictly localized observables is then obtained by abstract W*-algebrai
c arguments. This avoids dealing with the functional analytic properties o
f pointlike interacting fields\, which are difficult to control due to the
convergence problem of the infinite series of their form factors.\n\nIn e
xtension of these results\, we consider S-matrices with poles in the physi
cal 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 additiv
e term\, the so called ``bound state operator''. This technique applies to
a variety of theories\, e.g.\, the Bullough-Dodd model\, the Z(N)-Ising m
odel\, the affine Toda field theories and the Sine-Gordon model. The link
between these wedge-local fields and strictly local operator algebras is s
ubject to ongoing research.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ron Peled (Tel Aviv University)
DTSTART:20210824T140000Z
DTEND:20210824T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/62
DESCRIPTION:Title: Quantitative estimates for the effect of disorder on low-dimensiona
l lattice systems\nby Ron Peled (Tel Aviv University) as part of One w
orld IAMP mathematical physics seminar\n\n\nAbstract\nThe addition of an a
rbitrarily weak random field to low-dimensional classical statistical phys
ics models leads to the "rounding" of first-order phase transitions at all
temperatures\, as predicted in 1975 by Imry and Ma and proved rigorously
in 1989 by Aizenman and Wehr. This phenomenon was recently quantified for
the two-dimensional random-field Ising model (RFIM)\, proving that it exhi
bits exponential decay of correlations at all temperatures and all positiv
e random-field strengths. The talk will present new results on the quantit
ative aspects of the phenomenon for general systems with discrete and cont
inuous symmetries\, including Potts\, spin $O(n)$ and spin glass models. T
he discussion is further extended to real- and integer-valued height funct
ion models driven by a random field\, for which we study the fluctuations
of the gradient and height variables. Among the challenges presented by th
e latter setup is a conjectured roughening transition in the random-field
strength for the three-dimensional integer-valued random-field Gaussian fr
ee field.\nJoint work with Paul Dario and Matan Harel.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sasha Sodin (Queen Mary University London)
DTSTART:20210817T140000Z
DTEND:20210817T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/63
DESCRIPTION:Title: Lower bounds on the eigenfunctions of random Schroedinger operators
in a strip\nby Sasha Sodin (Queen Mary University London) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nIt is known tha
t the eigenfunctions of a random Schroedinger\noperator in a strip decay e
xponentially. In some regimes\, the same is\ntrue in higher dimensions. It
is however not clear whether the\neigenfunctions have an exact rate of ex
ponential decay. In the strip\,\nit is natural to expect that the rate sho
uld be given by the slowest\nLyapunov exponent\, however\, only the upper
bound has been previously\nestablished.\n\nWe shall discuss some recent pr
ogress on this problem\, and its\nconnection to a question\, perhaps inter
esting in its own right\, in the\ntheory of random matrix products. Based
on joint work with Ilya\nGoldsheid.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yvan Velenik (Université\; de Genè\;ve)
DTSTART:20210914T140000Z
DTEND:20210914T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/64
DESCRIPTION:Title: Fluctuations of a layer of unstable phase in the planar Ising model
\nby Yvan Velenik (Université\; de Genè\;ve) as part of On
e world IAMP mathematical physics seminar\n\n\nAbstract\nI'll first review
some of the known results about phase separation\, fluctuations of interf
aces and (equilibrium) aspects of metastability in the planar Ising model.
This will naturally lead us to consider a setup in which an interface sep
arates a layer of unstable phase along the boundary of the system from the
stable phase occupying the bulk. I'll then describe a recent work\, in wh
ich we prove that\, after a 1/3:2/3 scaling\, the distribution of this int
erface weakly converges to the distribution of the stationary trajectories
of an explicit Ferrari-Spohn diffusion. The proof relies on a rigorous re
duction to an effective interface model\, which I'll briefly sketch.\n\nTh
is is based on a joint work with Dima Ioffe\, Sébastien Ott and Senya Shl
osman\; arXiv:2011.11997 .\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rostyslav Hryniv (Ukrainian Catholic University)
DTSTART:20210928T140000Z
DTEND:20210928T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/65
DESCRIPTION:Title: Generalized soliton solutions of the Korteweg-de Vries equation
\nby Rostyslav Hryniv (Ukrainian Catholic University) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nThe Korteweg--de Vries (
KdV) equation is a non-linear dispersive equation describing shallow-water
waves and possessing many intriguing properties. One of them is existence
of the so-called soliton solutions representing solitary waves travelling
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 scattering probl
em for the family of associated Schroedinger operators\, as discovered by
S.Gardner\, J.Green\, M.Kruskal and R.Miura in 1967\, and the classical so
liton solutions of the KdV correspond precisely to the so-called reflectio
nless potentials (I.Kay and H.Moses\, 1956).\n\nThe aim of this talk is tw
o-fold. Firstly\, we characterise the family of all Schroedinger operators
with integrable reflectionless potentials and give an explicit formula pr
oducing all such potentials. Secondly\, we use the inverse scattering tran
sform approach to describe all solutions of the KdV equation whose initial
(t=0) profile is an integrable reflectionless potential. Such solutions w
ill stay integrable and reflectionless for all positive times and can be c
alled generalized soliton solutions of KdV. \n\nThis research extends and
specifies in several ways the previous work on reflectionless potentials
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.Karwows
ki\, and Z.Zhao in 1992. The talk is based on a joint project with B.Melny
k and Ya.Mykytyuk (Lviv Franko National University).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Loss (Georgia Institute of Technology)
DTSTART:20211005T140000Z
DTEND:20211005T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/66
DESCRIPTION:Title: Which magnetic fields support a zero mode?\nby Michael Loss (Ge
orgia Institute of Technology) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nI present some results concerning the size of m
agnetic fields that support zero modes for the three dimensional Dirac equ
ation and related problems for spinor equations. The critical quantity\, i
s the $3/2$ norm of the magnetic field $B$. The point is that the spinor s
tructure enters the analysis in a crucial way. This is joint work with Rup
ert Frank at LMU Munich.\n
LOCATION:https://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:20260422T225925Z
UID:IAMP_seminars/67
DESCRIPTION:Title: Eigenvalue bounds for Schrodinger operators with complex potentials
\nby Rupert L. Frank (California Institute of Technology and LMU Munic
h) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nW
e discuss open problems and recent progress concerning eigenvalues of Schr
odinger operators with complex potentials. We seek bounds for individual e
igenvalues or sums of them which depend on the potential only through some
L^p norm. While the analogues of these questions are (almost) completely
understood for real potentials\, the complex case leads to completely new
phenomena\, which are related to interesting questions in harmonic and com
plex analysis.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Klaus Fredenhagen (Universität Hamburg)
DTSTART:20210921T140000Z
DTEND:20210921T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/68
DESCRIPTION:Title: Towards an algebraic construction of Quantum Field Theory\nby K
laus Fredenhagen (Universität Hamburg) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nAlgebraic quantum field theory provide
s a conceptual and mathematically precise framework for the analysis of st
ructural features of quantum field theory.\nDuring the last decades\, it h
as in addition provided a generalization of quantum field theory to generi
c Lorentzian spacetimes\, and\, moreover\, an elegant reformulation of ren
ormalized perturbative quantum field theory. The principles used there act
ually determine also a C*-algebraic formulation which is surprisingly rich
and leads to some nonperturbative results.\nIn particular\, the time slic
e 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 Buchholz
(2020) and on joint work with Romeo Brunetti\, Michael Dütsch and Kasia R
ejzner (2021).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Nurowski (Polish Academy of Sciences\, Warsaw)
DTSTART:20211116T140000Z
DTEND:20211116T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/69
DESCRIPTION:Title: Split real form of Lie group G2: simple\, exceptional and naturally
appearing in physics\nby Paweł Nurowski (Polish Academy of Sciences\
, Warsaw) as part of One world IAMP mathematical physics seminar\n\n\nAbst
ract\nA simple exceptional Lie group G2 was predicted to exist by Wilhelm
Killing in 1887. Its geometric realization appeared later\, in 1893\; it i
s due to Friedrich Engel and Elie Cartan. They realized this group as a sy
mmetry group of two quite different geometric structures on five manifolds
. \nIn my talk I will try to explain how the idea of these G2 symmetric ge
ometric structures could came to minds of Cartan and Engel. My explanation
will be based on properties of the root diagram of G2. I will keep my lec
ture self contained\, so I will define the G2 root diagram and will explai
n how to use it. After nailing down the two 5-dimensional G2 -symmetric ge
ometries of Cartan and Engel\, I will show how they appear naturally in co
nstrained classical mechanics.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christophe Garban (Université Lyon 1)
DTSTART:20211012T140000Z
DTEND:20211012T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/70
DESCRIPTION:Title: Continuous symmetry breaking along the Nishimori line\nby Chris
tophe Garban (Université Lyon 1) as part of One world IAMP mathematical p
hysics seminar\n\n\nAbstract\nI will discuss a new way to prove continuous
symmetry breaking for (classical) spin systems on Z^d\, d\\geq 3 which do
es not rely on "reflection positivity". \nOur method applies to models wh
ose 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 continuous symm
etry breaking is based on two ingredients
\n1) the notion of "group sy
nchronization" in Bayesian statistics. In particular a recent result by Ab
be\, Massoulié\, Montanari\, Sly and Srivastava (2018) which proves group
synchronization when d\\geq 3.
\n2) a gauge transformation on both th
e disorder and the spin configurations due to Nishimori (1981).
\nI wi
ll end the talk with an application of these techniques to a deconfining t
ransition for U(1) lattice gauge theory on the Nishimori line. \nThis is a
joint work with Tom Spencer (https://arxiv.org/abs/2109.01617).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomaž Prosen (University of Ljubljana)
DTSTART:20211026T140000Z
DTEND:20211026T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/71
DESCRIPTION:Title: Random Matrix Spectral Fluctuations in Quantum Lattice Systems\
nby Tomaž Prosen (University of Ljubljana) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nI will discuss the problem of unre
asonable effectiveness of random matrix theory for description of spectral
fluctuations in extended quantum lattice systems. A class of interacting
spin systems has been recently identified - specifically\, the so-called d
ual unitary circuits - where the spectral form factor is proven to match w
ith circular ensembles of random matrix theory. The key ideas of novel met
hodology needed in the proofs will be discussed which are very different t
han the standard periodic-orbit based methods in quantum chaos of few body
semiclassical systems.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lea Bossmann (IST Austria)
DTSTART:20211102T140000Z
DTEND:20211102T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/72
DESCRIPTION:Title: Asymptotic expansion of low-energy excitations for weakly interacti
ng bosons\nby Lea Bossmann (IST Austria) as part of One world IAMP mat
hematical physics seminar\n\n\nAbstract\nWe consider a system of N bosons
in the mean-field scaling regime in an external trapping potential. We der
ive an asymptotic expansion of the low-energy eigenstates and the correspo
nding energies\, which provides corrections to Bogoliubov theory to any or
der in 1/N. We show that the structure of the ground state and of the non-
degenerate low-energy eigenstates is preserved by the dynamics if the exte
rnal trap is switched off. This talk is based on joint works with Sören P
etrat\, Peter Pickl\, Robert Seiringer and Avy Soffer.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gaultier Lambert (University of Zurich)
DTSTART:20211109T140000Z
DTEND:20211109T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/73
DESCRIPTION:Title: Universality for free fermions point processes\nby Gaultier Lam
bert (University of Zurich) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nI report on recent results obtained with A. Delepo
rte on universality of local statistics for the ground state of a free Fer
mi gas confined in a generic potential on ℝ^n. This model was introduced
by Macchi in 1975 and it forms a determinantal point process whose kernel
is the spectral projector associated to a Schrödinger operator −ℏ^2
Δ+V. I will explain how to obtain the asymptotics of the kernel of this p
rojector as ℏ→0 using methods from semiclassical analysis and discuss
some probabilistic consequences. In particular\, this implies universality
of microscopic fluctuations\, both in the bulk and around regular boundar
y points.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julian Sonner (University of Geneva)
DTSTART:20211123T140000Z
DTEND:20211123T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/74
DESCRIPTION:Title: Random matrices and black holes: new connections from holographic d
uality\nby Julian Sonner (University of Geneva) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nQuantum chaotic systems ar
e often defined via the assertion that their spectral statistics coincides
with\, or is well approximated by\, random matrix theory (RMT). In turn\,
the late-time ergodic behaviour of chaotic quantum systems is expected to
fall into a small number of universality classes of RMT dynamics. Recent
developments in holographic duality have made it possible to characterise
the ergodic late-time behaviour of black holes in asymptotically anti de S
itter space in similar terms. In this talk I will start by introducing the
basic ideas and notions of holographic duality (also known as AdS/CFT)\,
before moving on to these more recent developments\, mostly focussing on l
ow-dimensional examples.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Niklas Beisert (ETH Zurich)
DTSTART:20211130T140000Z
DTEND:20211130T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/75
DESCRIPTION:Title: Planar Integrability and Yangian Symmetry in N=4 Supersymmetric Yan
g–Mills\nby Niklas Beisert (ETH Zurich) as part of One world IAMP ma
thematical physics seminar\n\n\nAbstract\nThe discovery and utilisation of
integrability in the planar limit of certain gauge and string theory mode
ls has made available many exciting non-perturbative results and insights
for the AdS/CFT correspondence. In this talk I will introduce the prototyp
ical AdS/CFT duality between string theory on AdS₅×S⁵ and N=4 supersy
mmetric Yang–Mills theory\, and highlight the usefulness of planar integ
rability through some achievements. I will then present a formal notion of
integrability as a hidden Yangian symmetry of the action. Importantly\, t
his symmetry is realised on field theory objects in a non-standard fashion
for which a rigorous framework to deal with its implications is lacking.
I will demonstrate that this symmetry indeed leads to non-trivial relation
s for quantum correlations functions of this model. In order to make them
work out\, I also show in what sense the symmetry is compatible with BRST
gauge fixing.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nina Holden (ETH Zurich)
DTSTART:20211207T140000Z
DTEND:20211207T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/76
DESCRIPTION:Title: Conformal welding in Liouville quantum gravity: recent results and
applications\nby Nina Holden (ETH Zurich) as part of One world IAMP ma
thematical physics seminar\n\n\nAbstract\nLiouville quantum gravity (LQG)
is a natural model for a random fractal surface with origins in conformal
field theory and string theory. A powerful tool in the study of LQG is con
formal welding\, where multiple LQG surfaces are combined into a single LQ
G surface. The interfaces between the original LQG surfaces are typically
described by variants of the random fractal curves known as Schramm-Loewne
r evolutions (SLE). We will present a few recent conformal welding results
for LQG surfaces and applications to the integrability of SLE and LQG par
tition functions. Based on joint work with Ang and Sun and with Lehmkuehle
r.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolai Reshetikhin (University of California\, Berkeley)
DTSTART:20211214T140000Z
DTEND:20211214T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/77
DESCRIPTION:Title: On the asymptotic behavior of character measures in large tensor po
wers of finite dimensional representations of simple Lie algebras\nby
Nicolai Reshetikhin (University of California\, Berkeley) as part of One w
orld IAMP mathematical physics seminar\n\n\nAbstract\nLet $V$ be a finite
dimensional representation of a simple Lie algebra and $H$ be an positive
element of its Cartan subalgebra ("magnetic field"). On the space $V^{\\ot
imes N}$ we have a natural density matrix $N\\exp(-H)$ where $H$ acts diag
onally: $H(x\\otimes y\\otimes z\\dots)=Hx\\otimes y\\otimes z\\dots+x\\ot
imes Hy\\otimes z\\dots+x\\otimes y\\otimes Hz\\dots+\\dots$. The space $V
^{\\otimes N}$ decomposes into a direct\nsum of irreducible subrepresentat
ions:\n\\[\nV^{\\otimes N}\\simeq \\oplus_{\\lambda} V_\\lambda^{\\oplus m
(\\lambda\, N)}\n\\]\nwhere $\\lambda$ is the highest weight of the repres
entation $V_\\lambda$ and $m(\\lambda\, N)$\nis its multiplicity in the te
nsor product. The character distribution assigns the probability \n\\[\np_
{\\lambda}(N\,H)=\\frac{m(\\lambda\, N)Tr_{V_\\lambda}(e^{-H)})}{(Tr_V(e^{
-H}))^N}\n\\]\nto each $\\lambda$ in the decomposition of the tensor produ
ct.\n\nOne of the natural problems for this distribution is to find its as
ymptotic \nin the limit $N\\to \\infty$ and $\\lambda\\to \\infty$ in the
appropriate way.\nWhen $H=0$ the character distribution becomes a uniform
distribution.\nIn this case\, in such generality the asymptotic was studi
ed by Ph. Biane\, 1993 by T. Tate and S. Zelditch\, 2004. For tensor power
s 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 principal
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://researchseminars.org/talk/IAMP_seminars/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudio Dappiaggi (Università\; di Pavia)
DTSTART:20220111T140000Z
DTEND:20220111T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/78
DESCRIPTION:Title: Stochastic Partial Differential Equations and Renormalization à la
Epstein-Glaser\nby Claudio Dappiaggi (Università\; di Pavia) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe pre
sent a novel framework for the study of a large class of nonlinear stochas
tic partial differential equations\, which is inspired by the algebraic ap
proach to quantum\nfield theory. The main merit is that\, by realizing ran
dom fields within a suitable algebra of functional-valued distributions\,
we are able to use specific techniques proper of microlocal\nanalysis. The
se allow us to deal with renormalization using an Epstein-Glaser perspecti
ve\, 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 stochastic no
nlinear Schrödinger equation -- Joint work with Nicolò Drago\, Paolo Rin
aldi and Lorenzo Zambotti.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcin Lis (University of Vienna)
DTSTART:20220118T140000Z
DTEND:20220118T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/79
DESCRIPTION:Title: An elementary proof of phase transition in the planar XY model\
nby Marcin Lis (University of Vienna) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nUsing elementary methods we obtain a pow
er-law lower bound on the two-point function of the planar XY spin model a
t low temperatures. This was famously first rigorously obtained by Fröhli
ch and Spencer and establishes a Berezinskii-Kosterlitz-Thouless phase tra
nsition in the model. Our argument relies on a new loop representation of
spin correlations\, a recent result of Lammers on delocalisation of intege
r-valued height functions\, and classical correlation inequalities. This i
s joint work with Diederik van Engelenburg.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Schweigert (Universität Hamburg)
DTSTART:20211221T140000Z
DTEND:20211221T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/80
DESCRIPTION:Title: More about CFT correlators\nby Christoph Schweigert (Universit
ät Hamburg) as part of One world IAMP mathematical physics seminar\n\n\nA
bstract\nI will explain two recent developments concerning bulk fields in\
ntwo-dimensional rational conformal field theories: the importance of\nthe
relative Serre functor to study bulk fields for logarithmic\nconformal fi
eld theories and the use of stringnet techniques to\nsimplify the construc
tion of correlators for semisimple modular\ntensor categories.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vojkan Jaksic (McGill University)
DTSTART:20220322T140000Z
DTEND:20220322T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/81
DESCRIPTION:Title: Approach to equilibrium in translation-invariant quantum systems: s
ome structural results\nby Vojkan Jaksic (McGill University) as part o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nWe formulate
the problem of approach to equilibrium in algebraic quantum statistical me
chanics and study some of its structural aspects\, focusing on the relatio
n between the zeroth law of thermodynamics (approach to equilibrium) and t
he second law (increase of entropy). Our main result is that approach to e
quilibrium is necessarily accompanied by a strict increase of the specific
(mean) entropy. In the course of our analysis\, we introduce the concept
of quantum weak Gibbs state which is of independent interest.\n\nThis is a
joint work with C. Tauber and C.-A. Pillet\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Schiavina (ETH Zürich)
DTSTART:20220125T140000Z
DTEND:20220125T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/83
DESCRIPTION:Title: Ruelle Zeta Function from Field Theory\nby Michele Schiavina (E
TH Zürich) as part of One world IAMP mathematical physics seminar\n\n\nAb
stract\nI will discuss a field-theoretic interpretation of Ruelle's zeta f
unction\, which "counts" prime geodesics on hyperbolic manifolds\, as the
partition function for a topological field theory (BF) with an unusual gau
ge fixing condition available on contact manifolds. This suggests a rephra
sing of a conjecture due to Fried\, on the equivalence between Ruelle's ze
ta function (at zero) and the analytic torsion\, as gauge-fixing independe
nce in the Batalin--Vilkovisky formalism.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daisuke Shiraishi (Kyoto University)
DTSTART:20220201T140000Z
DTEND:20220201T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/84
DESCRIPTION:Title: Recent progress on loop-erased random walk in three dimensions\
nby Daisuke Shiraishi (Kyoto University) as part of One world IAMP mathema
tical physics seminar\n\n\nAbstract\nLoop-erased random walk (LERW) is a m
odel for a random simple path\, which is created by running a simple rando
m walk and\, whenever the random walk hits its path\, removing the resulti
ng loop and continuing. LERW was originally introduced by Greg Lawler in 1
980. Since then\, it has been studied extensively both in mathematics and
physics literature. Indeed\,\nLERW has a strong connection with other mode
ls in statistical physics\, especially the uniform spanning tree which ari
ses in statistical physics in conjunction with the Potts model. In this ta
lk\, 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://researchseminars.org/talk/IAMP_seminars/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Makiko Sasada (University of Tokyo)
DTSTART:20220308T140000Z
DTEND:20220308T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/85
DESCRIPTION:Title: Topological structures and the role of symmetry in the hydrodynamic
limit of nongradient models\nby Makiko Sasada (University of Tokyo) a
s part of One world IAMP mathematical physics seminar\n\n\nAbstract\nRecen
tly\, we introduce a general framework in order to systematically investig
ate hydrodynamics limits of various microscopic stochastic large scale int
eracting systems in a unified fashion. In particular\, we introduced a new
cohomology theory called the uniformly cohomology to investigate the unde
rlying 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 diffusion
matrix associated to the macroscopic hydrodynamic equation. Furthermore\,
we rigorously formulate and prove for a relatively general class of models
Varadhan’s decomposition of closed forms\, which plays a key role in th
e proof of hydrodynamic limits of nongradient models. Our result is applic
able for many important models including generalized exclusion processes\,
multi-species exclusion processes\, exclusion processes on crystal lattic
es and so on. Based on joint papers with Kenichi Bannai and Yukio Kametani
\n(https://arxiv.org/abs/2009.04699\, https://arxiv.org/abs/2111.0893
4).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/85/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Serena Cenatiempo (GSSI L'Aquila)
DTSTART:20220329T140000Z
DTEND:20220329T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/86
DESCRIPTION:Title: Trial states for the zero temperature dilute Bose gas\nby Seren
a Cenatiempo (GSSI L'Aquila) as part of One world IAMP mathematical physic
s seminar\n\n\nAbstract\nNon-relativistic interacting bosons at zero tempe
rature\, in two and three dimensions\, are expected to exhibit a fascinati
ng critical phase\, famously known as condensate phase. Even though a proo
f of Bose-Einstein condensation in the thermodynamic limit is still beyond
reach of the current available methods\, the mathematical physics communi
ty has recently gained an enhanced comprehension of other aspects of the m
acroscopic behavior of low temperature Bose gases\, in several interesting
regimes. In this talk we review part of these advances\, by describing tr
ial states for the dilute three dimensional Bose gas\, capturing the celeb
rated Lee-Huang-Yang sub-leading correction to the ground state energy. We
conclude with some open questions and perspectives.\n\nBased on joint wor
ks with G. Basti\, C. Boccato\, C. Brennecke\, C. Caraci\, A. Olgiati\, G.
Pasqualetti and B. Schlein.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jerzy Lewandowski (University of Warsaw)
DTSTART:20220315T140000Z
DTEND:20220315T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/87
DESCRIPTION:Title: Horizon equations\nby Jerzy Lewandowski (University of Warsaw)
as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe
extremity assumptions imposes a set of non-trivial equations on the\nintri
nsic and extrinsic geometry of the horizon. Some of them already\ngot 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\nexistenc
e and uniqueness of extremal black hole solutions to Einstein's\nequations
. In 4d spacetime\, an integrability condition for the NHG\nequation is av
ailable that is satisfied by the family of non-extremal\nhorizon geometrie
s\, namely by those that are of the Petrov type D. What\nis special about
that equation\, is that its solutions exhibit similar\nproperties to those
proved in the global black hole spacetime theory:\nspherical topology of
horizon cross sections\, rigidity\, no-hair.\n\nExtension of the research
to the horizons that had a Hopf bundle\nstructure led to interesting resul
ts about the global structure of the\nKerr-NUT-(A)dS spaces. Misner's co
nstruction was generalised to the\ncase when none of the three parameters
(NUT\, Kerr\, and the cosmological\nconstant) vanishes. The resulting fami
ly contains also exact solutions\nto Einstein's equations that admit no ho
rizon or nowhere time like\nKilling vector and describe a topologically s
pherical universe evolving\nfrom the past scry to the future scry in a non
-singular manner.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martin Zirnbauer (University of Cologne)
DTSTART:20220215T140000Z
DTEND:20220215T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/88
DESCRIPTION:Title: Field theory of Anderson transitions reviewed: Color-Flavor Transfo
rmation\nby Martin Zirnbauer (University of Cologne) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nThis talk is in two p
arts. First\, the field-theoretic approach to (de-)localization in Anderso
n-type models for disordered electrons is reviewed\, with emphasis placed
on the presence of a hyperbolic target-space sector and the expected patte
rn of spontaneous symmetry breaking. The second part is a review of the "C
olor-Flavor (CF) Transformation" (MZ\, 1996). Conceived as a variant of th
e Efetov-Wegner supersymmetry method\, the CF Transformation is tailored t
o quantum systems with disorder distributed according to Haar measure for
any compact Lie group of classical type (A\, B\, C\, or D). It has been ap
plied to Dyson's Circular Ensembles\, random-link network models\, quantum
chaotic graphs\, disordered Floquet dynamics\, and more. It is reviewed h
ere as a rigorous tool to derive the effective field theory for systems in
the metallic regime.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Skibsted (Aarhus University)
DTSTART:20220208T140000Z
DTEND:20220208T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/89
DESCRIPTION:Title: Stationary scattering theory\, the N-body long-range case\nby E
rik Skibsted (Aarhus University) as part of One world IAMP mathematical ph
ysics seminar\n\n\nAbstract\nWithin the class of Dereziński-Enss pair-pot
entials which includes Coulomb potentials and for which asymptotic complet
eness is known\, we show that all entries of the N-body quantum scattering
matrix have a well-defined meaning at any given non-threshold energy. As
a function of the energy parameter the scattering matrix is weakly continu
ous. This result generalizes a similar one obtained previously by Yafaev f
or systems of particles interacting by short-range potentials. As for Yafa
ev’s works we do not make any assumption on the decay of channel eigenst
ates. The main part of the proof consists in establishing a number of Kato
-smoothness bounds needed for justifying a new formula for the scattering
matrix. Similarly we construct and show strong continuity of channel wave
matrices for all non-threshold energies. The set of so-called stationary c
omplete energies has full measure. We show that the scattering and channel
wave matrices constitute a well-defined ‘scattering theory’ at such e
nergies\, in particular at any stationary complete energy the scattering m
atrix is unitary\, strongly continuous and characterized by asymptotics of
minimum generalized eigenfunctions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marek Biskup (UCLA)
DTSTART:20220301T140000Z
DTEND:20220301T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/90
DESCRIPTION:Title: Extremal points of random walks on planar and tree graphs\nby M
arek Biskup (UCLA) as part of One world IAMP mathematical physics seminar\
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 situati
ons where the random walk has an approximate scale-invariant structure and
the associated local time process is thus logarithmically correlated in s
pace. Two geometric settings will be considered: the simple random walk on
finite subsets of the square lattice and the random walk on homogeneous t
rees of finite depth. In the former case\, a full description will be give
n of the scaling limit of thick\, thin and avoided points for the walk run
up to the times proportional to the cover time. For the latter setting\,
the law of the most frequently visited leaf-vertex\, and the time spent th
ere\, will be given in the limit of the tree depth tending to infinity. In
both cases\, the spatial laws will be determined by a corresponding multi
plicative chaos measure. Based on joint papers with Y. Abe\, S. Lee and O.
Louidor.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenzo Taggi (Sapienza Università di Roma)
DTSTART:20220222T140000Z
DTEND:20220222T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/91
DESCRIPTION:Title: Macroscopic loops in the interacting Bose gas\, Spin O(N) and relat
ed models\nby Lorenzo Taggi (Sapienza Università di Roma) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nWe consider a g
eneral system of interacting random loops which includes several models 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 in
teracting Bose gas in discrete space. We present an overview on these mode
ls\, introduce some of the main open questions about the size and the geom
etry of the loops\, and present some recent results about the occurrence o
f macroscopic loops in dimensions d > 2 as the inverse temperature is larg
e enough.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edward Witten (IAS)
DTSTART:20220412T140000Z
DTEND:20220412T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/92
DESCRIPTION:Title: Black Hole Entropies and Algebras\nby Edward Witten (IAS) as pa
rt of One world IAMP mathematical physics seminar\n\n\nAbstract\nI will re
view the idea of black hole entropy\, as originally discovered by Bekenste
in and Hawking roughly half a century ago\, and then explain how to interp
ret black hole entropy in terms of an appropriate algebra of observables.\
n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/92/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Deepak Dhar (IISER Pune)
DTSTART:20220426T140000Z
DTEND:20220426T150000Z
DTSTAMP:20260422T225925Z
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\nAbstrac
t\nI consider a system of hard rigid rods of length $k$ and width $1$\, o
n $d$-dimensional hypercubic lattices. \nI will show that in the limit of
large $k$\, the entropy per site at full packing $ s(d\,k)$ for $d=2$ s
atisfies \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 phase tra
nsitions when chemical potential is increased: from a low density isotropi
c phase to an intermediate density nematic phase\, and on further increas
e to a high-density phase with no orientational order. I will present ev
idence to suport the conjecture that\, for large $k$\, the second phase t
ransition is a first order transition with a discontinuity in density as a
function of the chemical potential\, in all dimensions greater than 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 $\\e
psilon_2(k\,d)$\, we have for all $d \\geq 2$\n$$\\lim_{ k \\rightarrow \
\infty} \\frac{ \\epsilon_1(d\, k) k^2}{\\log k} =1\,$$\n$$\\lim_{k \\righ
tarrow \\infty} \\frac{ \\exp\\left[ \\frac{\\mu^*(d\, k)}{k} \\right] \\l
og k}{k} =1\,$$\n$$\\lim_{k \\rightarrow \\infty} \\frac{\\epsilon_2(d\,
k) k ^m}{\\epsilon_1(d\,k)} =0\, ~{\\rm for~ all}~m>0.$$\n\nReferences: D
eepak Dhar and R. Rajesh\, Phys. Rev. E 103\, 042130 (2021)\;\n Aagam Shah
\, D. Dhar and R. Rajesh\, Phys. Rev. E. 105\, 034103 (2022).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech Dybalski (Adam Mickiewicz University)
DTSTART:20220517T140000Z
DTEND:20220517T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/94
DESCRIPTION:Title: Interacting massless excitations in 1+1 dimensional QFT\nby Woj
ciech Dybalski (Adam Mickiewicz University) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nMassless 1+1 dimensional quantum f
ield 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 interpretation (
asymptotic completeness) can be expected already at the level of two-body
scattering. This effect will be illustrated by certain wedge-local models
of interacting Wigner particles. In the second part of the talk I will mov
e to the more exotic case of infraparticles\, i.e.\, excitations which are
not of Wigner type. It is known that infraparticles abound in 1+1 massles
s QFT\, even in the familiar case of free field theory. A natural definiti
on of a scattering amplitude for infraparticles will be proposed and teste
d in this latter model. Paradoxically\, infraparticles in free field theor
y exhibit non-trivial scattering. \n\nThe talk is based on joint works wit
h Yoh Tanimoto (CMP 305\, 427-440 (2011)) and Jens Mund (arXiv:2109.02128)
.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vieri Mastropietro (University of Milan)
DTSTART:20220510T140000Z
DTEND:20220510T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/95
DESCRIPTION:Title: Anomalies and non-perturbative QFT\nby Vieri Mastropietro (Univ
ersity of Milan) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nAdler and Bardeen in 1969 established the non-renormalization
of the chiral anomaly\, writing it as a perturbative expansion which is o
rder by order vanishing\; since then\, this property has found uncountable
applications\, including the Standard Model consistence via the anomaly c
ancellation condition (Bouchiat\, Iliopoulos\, Meyer 1972). After reviewi
ng briefly this notion\, we prove the anomaly non renormalization at a non
-perturbative level in the case of lattice vector boson-fermion models in
d=1+1 (uniformly in the lattice) and in d=3+1 (up to a cut-off of the orde
r of the inverse coupling). The proof relies on bounds on the large distan
ce decay of correlations and Ward Identities\, both exact and emerging. In
the case of chiral models\, like the effective electroweak theory with qu
artic Fermi interaction in d=3+1\, some Ward Identites are violated and th
e anomaly can be proved to vanish up to subdominant corrections which are
rigorously bounded\, under the cancellation condition on charges and with
a cut-off of the order of the inverse coupling. Open problems and conjectu
res will be finally discussed.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Saffirio (University of Basel)
DTSTART:20220621T140000Z
DTEND:20220621T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/96
DESCRIPTION:Title: Mean-field evolution and semiclassical limit of many interacting fe
rmions\nby Chiara Saffirio (University of Basel) as part of One world
IAMP mathematical physics seminar\n\n\nAbstract\nWe will review recent pro
gresses in the derivation of effective evolution equations for the dynamic
s of many weakly interacting fermions. We will focus on the mean-field reg
ime and couple it with a semiclassical limit to obtain\, as the number of
particles goes to infinity\, the Hartree-Fock and the Vlasov equations. We
will comment on the class of singular interactions and quantum states tha
t we are able to treat\, drawing a comparison with the PDE theory of the l
imiting equations.\nBased on joint works with J. Chong and L. Laflèche.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Doyon (King's College London)
DTSTART:20220531T140000Z
DTEND:20220531T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/98
DESCRIPTION:Title: Ergodicity\, large-scale correlations and hydrodynamics in many-bod
y systems\nby Benjamin Doyon (King's College London) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nLong-time behaviours
in statistical ensembles of many-body systems are notoriously difficult to
access. Hydrodynamics\, which is the theory for the emergent large-scale
dynamics\, gives a lot of information\, such as exact asymptotics of corre
lation functions. It turns out that at the Euler scale\, the emergent theo
ry for extended systems is largely universal. I will discuss a number of s
uch universal results in one dimension of space. Some can be shown rigorou
sly: a notion of ergodicity at all frequencies hold for correlation functi
ons in stationary states of all short-range quantum spin chains. The Boltz
mann-Gibbs principle\, where local observables project onto hydrodynamic m
odes in two-point functions\, and the linearised Euler equations\, are als
o established. The complete space of hydrodynamic modes is the space of ``
extensive conserved quantities”\, which is defined unambiguously. I will
illustrate these concepts in integrable systems\, using generalised hydro
dynamics. For correlations in non-stationary states\, much less is establi
shed. I will describe a macroscopic fluctuation theory for the Euler scale
which provides a framework for these. In particular\, I will explain how
a new type of long-range correlations\, hitherto not observed\, appear whe
n the system is subject to fluid motion\, which breaks the paradigm that s
eparate fluid cells are not correlated.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Owen Gwilliam (University of Massachusetts Amherst)
DTSTART:20220628T140000Z
DTEND:20220628T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/99
DESCRIPTION:Title: Observables in the Batalin-Vilkovisky formalism: from Feynman diagr
ams to commutative diagrams\nby Owen Gwilliam (University of Massachus
etts Amherst) as part of One world IAMP mathematical physics seminar\n\n\n
Abstract\nThis talk will discuss a convergence between perturbative QFT an
d higher algebra\, in the sense of homological algebra\, operads\, and hig
her categories\, although we do not expect the listener to have any expert
ise in those topics. A key notion here is a factorization algebra\, which
captures the local-to-global nature of the observables of a field theory a
nd which is due to Beilinson and Drinfeld. With a focus on the example of
Chern-Simons theory\, we will discuss how the BV/factorization package off
ers a new view on the emergence of algebraic structures\, like braided mon
oidal categories\, from physics.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/99/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Correggi (Politecnico di Milano)
DTSTART:20220705T140000Z
DTEND:20220705T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/100
DESCRIPTION:Title: Ground State Properties in the Quasi-Classical Regime\nby Mich
ele Correggi (Politecnico di Milano) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nWe study the ground state energy and grou
nd states of systems coupling non-relativistic quantum particles and force
-carrying Bose fields\, such as radiation\, in the quasi-classical approxi
mation. The latter is very useful whenever the force-carrying field has a
very large number of excitations\, and thus behaves in a semiclassical way
\, while the non-relativistic particles\, on the other hand\, retain their
microscopic features. We prove that the ground state energy of the fully
microscopic model converges to the one of a nonlinear quasi classical func
tional depending on both the particles' wave function and the classical co
nfiguration of the field. Equivalently\, this energy can be interpreted as
the lowest energy of a Pekar-like functional with an effective nonlinear
interaction for the particles only. If the particles are confined\, the gr
ound state of the microscopic system converges as well\, to a probability
measure concentrated on the set of minimizers of the quasi classical energ
y.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello (Perimeter Institute)
DTSTART:20220524T140000Z
DTEND:20220524T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/101
DESCRIPTION:Title: Form factors of gauge theory as correlators of a vertex algebra\nby Kevin Costello (Perimeter Institute) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nForm factors are scattering amplitu
des in the presence of a local operator. I will explain that\, for certain
gauge groups\, form factors of self-dual Yang-Mills theory (with some add
itional fields) are the correlators of a vertex algebra. This is joint wor
k with Natalie Paquette\, and is closely related to the celestial holograp
hy program.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hirosi Ooguri (Caltech & Kavli IPMU)
DTSTART:20220419T140000Z
DTEND:20220419T150000Z
DTSTAMP:20260422T225925Z
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\nAbstrac
t\nI will review aspects of symmetry in quantum field theory and combine t
hem with the AdS/CFT correspondence to derive constraints on symmetry in q
uantum gravity. The quantum gravity constraints to be discussed include th
e no-go theorem on global symmetry\, the completeness of gauge charges\, a
nd the decomposition of high energy states into gauge group representation
s.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jacob Shapiro (Princeton)
DTSTART:20220405T140000Z
DTEND:20220405T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/103
DESCRIPTION:Title: Continuum and strongly disordered topological insulators\nby J
acob Shapiro (Princeton) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nA natural question to ask in the field of topological
insulators is whether continuum descriptions on L^2(R^d) and effective di
screte descriptions on l^2(Z^d) agree\, at the level of the long time dyna
mics 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 effect. Th
e basic tool to approach the problem is homotopies of Fredholm operators.
This same tool is also shown to apply to other problems in topological ins
ulators\, such as the bulk-edge correspondence for Z_2 time-reversal invar
iant strongly disordered discrete systems. This talk is based on joint wor
ks with Michael I. Weinstein and with Jeff Schenker and Alex Bols.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Teufel (University of Tübingen)
DTSTART:20220712T140000Z
DTEND:20220712T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/104
DESCRIPTION:Title: A slightly different look at the bulk-edge correspondence in quant
um Hall systems\nby Stefan Teufel (University of Tübingen) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nThe bulk-edge
correspondence of transport coefficients in quantum Hall systems is usuall
y shown for systems with a (mobility) gap in the bulk and at zero temperat
ure. I will present recent results showing equality of magnetization in th
e bulk and edge current in microscopic models without and with interaction
between electrons. This equality holds at positive temperature and withou
t assuming a (mobility) gap in the bulk\, and is robust to perturbations n
ear the edges. I then discuss how the equality of transport coefficients c
an be recovered from this form of bulk-edge correspondence\, at least in s
ome cases. My talk is based on joint work with Horia Cornean\, Jonas Lampa
rt\, Massimo Moscolari\, and Tom Wessel.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Ueltschi (University of Warwick)
DTSTART:20220503T140000Z
DTEND:20220503T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/105
DESCRIPTION:Title: Random loop models and their universal behaviour in dimension 3+\nby Daniel Ueltschi (University of Warwick) as part of One world IAMP m
athematical physics seminar\n\n\nAbstract\nI will discuss several loop sou
p models that represent classical or quantum systems\nof statistical physi
cs. These systems undergo phase transitions that are characterised\nby the
occurrence of macroscopic loops. \n\nAs it turns out\, the joint distribu
tion of the loop lengths exhibits a universal behaviour:\nIn 3+ dimension
it is always given by a Poisson-Dirichlet distribution. The heuristics\nis
based on the fact that the loops are so intertwined that they behave effe
ctively in\nmean-field fashion. Hence the connection to the split-merge pr
ocess\, whose invariant\nmeasure is Poisson-Dirichlet.\n\nI will also disc
uss consequences about symmetry breaking in certain quantum spin\nsystems.
\n\nThis talk is based on collaborations over the years with D. Gandolfo\,
J. Ruiz\, C. Goldschmidt\,\nP. Windridge\, V. Betz\, S. Grosskinsky\, A.
Lovisolo\, C. Benassi\, J. Bjö\;rnberg\,\nJ. Frö\;hlich.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Aizenman (Princeton)
DTSTART:20220607T140000Z
DTEND:20220607T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/106
DESCRIPTION:Title: A new perspective on a pair of two dimensional phenomena: delocali
zation in random height functions and the Berezinskii-Kosterlitz-Thouless
phase of O(2) symmetric spin models\nby Michael Aizenman (Princeton) a
s part of One world IAMP mathematical physics seminar\n\n\nAbstract\nDeloc
alization in integer-restricted Gaussian field\, and other random height f
unctions formulated over planar doubly-periodic lattices\, is shown to imp
ly slow (power law) decay of correlations in the corresponding dual O(2) s
ymmetric two-component spin model. The link proceeds through a lower bound
on the spin-spin correlation in terms of the probability of their sites b
eing on a common level loop of the dual random height function. Motivated
by this observation\, we have extended the recent proof by P. Lammers of
delocalization transition in two dimensional graphs of degree three\, to a
ll doubly periodic graphs\, in particular to Z^2. The extension is establi
shed through a monotonicity argument based on lattice inequalities of O. R
egev and N. Stephens-Davidowitz. Taken together the results yield a new p
erspective on the BKT phase transition in O(2)-invariant models and comple
te a new proof of delocalization in two-dimensional integer-valued height
functions. (Both phenomena are unique to two dimension\, and have been pre
viously proven and studied by other means). \nThat talk is based on a joi
nt work by M. Aizenman\, M. Harel J. Shapiro and R. Peled.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Camillo De Lellis (IAS)
DTSTART:20221129T140000Z
DTEND:20221129T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/107
DESCRIPTION:Title: Anomalous dissipation for the forced Navier-Stokes equations\n
by Camillo De Lellis (IAS) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nConsider smooth (or at least Leray) solutions to 3d
Navier-Stokes\n\\[\n\\left\\{\n\\begin{array}{ll}\n\\partial_t u^\\vareps
ilon + {\\rm div}\\\, (u^\\varepsilon \\otimes u^\\varepsilon ) + \\nabla
p^\\varepsilon = \\varepsilon \\Delta u^\\varepsilon\\\\ \\\\\nu^\\varepsi
lon (0\, \\cdot) = u^\\varepsilon_0\\\, .\n\\end{array}\\right.\n\\]\nWhil
e the balance of the energy is\n\\[\n\\frac{d}{dt} \\frac{1}{2} \\int |u|^
2 (x\,t)\\\, dx = - \\varepsilon \\int |Du|^2 (x\,t)\\\, dx\\\, \,\n\\]\ni
t is a tenet of the theory of fully developed turbulence that in a variety
of situations the left hand side should typically be independent of $\\va
repsilon$: the mechanism is not supposed to be ignited by high oscillation
s in the initial data\, which would trigger an ``immediate'' dissipation t
hrough the viscosity\, but it is rather thought to be an effect of the qua
dratic nonlinearity. It is on the other hand very challenging to produce r
igorous examples. If the bounds on $u_0^\\varepsilon$ are too strong\, the
well-posedness theory for Euler obstructs the anomalous dissipation up un
til the first blow-up time of Euler. With sufficiently coarse bounds Euler
can be shown to have a variety of dissipative solutions\, but it is 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 equ
ation and we can prove rigorously that\, as soon as the regularity of the
force drops below the known thresholds for the well-posedness of classical
Euler\, it is in fact possible to show anomalous dissipation.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karol Kozlowski (ENS Lyon)
DTSTART:20221018T140000Z
DTEND:20221018T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/109
DESCRIPTION:Title: Towards an exact rigorous construction of the Sinh-Gordon quantum
field theory in 1+1 dimensions\nby Karol Kozlowski (ENS Lyon) as part
of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe bootstra
p program was devised in the late 70s/early 80s as a possible path for a f
ully explicit construction of numerous massive integrable quantum field th
eories in 1+1 dimensions. Ultimately\, it allows one to express the physic
ally pertinent observables in these models --- the multi-point correlation
functions also called Wightman functions --- in terms of form factor seri
es expansion. On technical grounds\, the latter correspond to fully explic
it series of multiple integrals in which the $n^{\\rm th}$ summand is give
n by a $n$-fold integral. The well definiteness of such a construction amo
unts to proving the convergence of these series expansions and this was a
basically an open problem.\n\nIn this talk\, I will review the boostrap ap
proach to the construction of the Sinh-Gordon quantum field theory. In par
ticular\, I will discuss the type of representations one gets for the mult
i-point correlation functions in this model. Then\, I will discuss the rec
ent progress I achieved on the convergence problem for the form factor ser
ies arising in the description of space-like separated two-point functions
. The proof of the convergence of amounts to obtaining a sufficiently shar
p estimate on the leading large-$n$ behaviour of the $n$-fold integral ari
sing in those series. This appeared possible by refining some of the techn
iques that were fruitful in the analysis of the large-$n$ behaviour of int
egrals over the spectrum of $n\\times n$ random Hermitian matrices.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/109/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dorothea Bahns (Georg-August-Universität Göttingen)
DTSTART:20220927T140000Z
DTEND:20220927T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/110
DESCRIPTION:Title: The Sine Gordon Model in hyperbolic signature\nby Dorothea Bah
ns (Georg-August-Universität Göttingen) as part of One world IAMP mathem
atical physics seminar\n\n\nAbstract\nI will review some recent results 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 operators on a
Hilbert space)\, the other will be\nto explain how the adiabatic switching
function can be removed in\nexpectation values in thermal states. The met
hods presented are a\nmixture of "old and new" in constructive and algebra
ic quantum field theory.\n\nThis is joint work with Kasia Rejzner\, Klaus
Fredenhagen\, and Nicola\nPinamonti.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Slava Rychkov (IHES)
DTSTART:20220920T140000Z
DTEND:20220920T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/111
DESCRIPTION:Title: Tensor Renormalization Group at Low Temperatures\nby Slava Ryc
hkov (IHES) as part of One world IAMP mathematical physics seminar\n\n\nAb
stract\nTensor RG is a real-space approach to renormalization in lattice m
odels. It shows impressive numerical results\, but its rigorous theory is
still in its infancy. I will start by reminding the basics of Tensor RG\,
and what makes it potentially more powerful than Wilson-Kadanoff approach.
I will then explain how Tensor RG can be used to understand the Ising mod
el in nonzero magnetic field at low temperatures. This gives an alternativ
e to the Pirogov-Sinai theory and to the renormalization group methods in
the contour representation from the 1980’s. Joint work with Tom Kennedy\
, to appear soon.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomohiro Sasamoto (Tokyo Institute of Technology)
DTSTART:20220719T140000Z
DTEND:20220719T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/112
DESCRIPTION:Title: Mapping macroscopic fluctuation theory for the symmetric simple ex
clusion process to a classically integrable system\nby Tomohiro Sasamo
to (Tokyo Institute of Technology) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nThe large deviation principle for symmetric
simple exclusion process(SEP) had been established by \nKipnis\, Olla\, V
aradhan in 1989 [1]. A somewhat different formulation\, known as the macro
scopic \nfluctuation theory (MFT)\, was initiated and developed by Jona-La
sinio et al in 2000’s [2]. The basic \nequations of the theory\, MFT equ
ations\, are coupled nonlinear partial differential equations and \nhave r
esisted exact analysis except for stationary situation. In this talk we in
troduce a novel \ngeneralization of the Cole-Hopf transformation and show
that it maps the MFT equations for SEP \nto the classically integrable Abl
owitz-Kaup-Newell-Segur(AKNS) system. This allows us to solve \nthe equati
ons exactly in time dependent regime by adapting standard ideas of inverse
scattering method. \n\nThe talk is based on a joint work with Kirone Mall
ick and Hiroki Moriya [3]. \n\nReferences\n\n[1] C. Kipnis\, S. Olla\, S.
R. S. Varadhan\, \nHydrodynamics and large deviations for simple exclusion
processes\, Comm. Pure Appl. Math.\, 42:115–137\, 1989.\n\n[2] L. Berti
ni\, A. De Sole\, D. Gabrielli\, G. Jona-Lasinio\, and C. Landim\,\nMacros
copic fluctuation theory\, Rev. Mod. Phys.\, 87:593–636\, 2015.\n\n[3] K
irone Mallick\, Hiroki Moriya\, Tomohiro Sasamoto\,\nExact solution of the
macroscopic fluctuation theory for the symmetric exclusion process\,\narX
iv: 2202.05213\, to appear in Phys. Rev. Lett.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/112/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sohei Ashida (Gakushuin University)
DTSTART:20221025T140000Z
DTEND:20221025T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/113
DESCRIPTION:Title: Mathematics of molecular structures and dynamics\nby Sohei Ash
ida (Gakushuin University) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nI will talk about mathematically rigorous results c
oncerned with studies\nof molecules. The subject corresponds to N-body pro
blems of the\nSchrödinger equation from the standpoint of mathematics. Fi
rst\, we will\nconsider the spectrum and long-time asymptotic behaviors\,
focusing on\nscattering matrices of N-body Schrödinger equation. Next we
will\nconsider quantitative studies based on the Born-Oppenheimer\napproxi
mation. Results related to estimates of electronic energy levels\nsuch as
the upper bound of electronic density and results concerned with\nthe Hart
ree-Fock equation will be presented.\n\nReferences: [1] Kyushu J.\nMath. 7
5\, 277-294 (2021) (arXiv:2002.07426) [2] Hiroshima Math. J.\, 52\,\n177-2
16 (2022) (arXiv:1811.07527) [3] arXiv:2012.09397 to appear in\nTohoku Mat
h. J. [4] arXiv:2112.09521 to appear in Hokkaido Math. J. [5]\narXiv:2205.
10300\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Duch (Adam Mickiewicz University)
DTSTART:20221004T140000Z
DTEND:20221004T150000Z
DTSTAMP:20260422T225925Z
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 mathematical p
hysics seminar\n\n\nAbstract\nMost stochastic PDEs arising in physics\, su
ch 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 random t
erms. Equations of this type are called singular. Regularization and renor
malization are usually necessary to give mathematical meaning to such equa
tions. In the talk\, I will present a novel technique of solving singular
stochastic PDEs. The technique is based on the renormalization group flow
equation. It is applicable to a large class of parabolic or elliptic SPDEs
with fractional Laplacian\, additive noise and polynomial non-linearity.
It covers equations in the whole super-renormalizable regime. A nice featu
re of the method is that it avoids the algebraic and combinatorial problem
s arising in different approaches. Based on arXiv:2109.11380 and arXiv:220
1.05031.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Kopper (Ecole Polytechnique)
DTSTART:20221011T140000Z
DTEND:20221011T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/115
DESCRIPTION:Title: On asymptotically free scalar fields\nby Christoph Kopper (Eco
le Polytechnique) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nI present recent work (Annales Henri Poincaré 2022) analysi
ng the flow equations of the renormalisation group in the mean field appro
ximation. There it is shown that these equations for scalar fields in four
dimensional euclidean space\, have solutions which are UV asymptotically
free. I comment on this result\, also in view of the literature\, in parti
cular with regard to the triviality of \\varphi^4_4-theory. We close with
an outlook on future perspectives.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jian Ding (Peking University)
DTSTART:20220830T140000Z
DTEND:20220830T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/116
DESCRIPTION:Title: Repeated emergence of 4/3-exponent\nby Jian Ding (Peking Unive
rsity) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\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 fact been
hinted in Leighton-Shor (1989) and Talagrand (2014) where the 4/3-exponent
emerges in a random matching problem. Finally\, I will present the heuris
tic computation which leads to the emergence of the 4/3-exponent.\n\nWhile
I will review related progress on these topics\, the two papers featuring
4/3-exponent are with Subhajit Goswami and with Mateo Wirth.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Strohmaier (University of Leeds)
DTSTART:20220726T140000Z
DTEND:20220726T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/117
DESCRIPTION:Title: A mathematical analysis of Casimir interactions and determinant fo
rmulae\nby Alexander Strohmaier (University of Leeds) as part of One w
orld IAMP mathematical physics seminar\n\n\nAbstract\nI will explain a mat
hematical treatment of Casimir interactions of perfect conductors in which
the Casimir energy is written as the trace of an operator without the nee
d for regularisations. I will also show some consequences of this approach
\, relations to microlocal analysis\, and will prove a trace formula that
allows to compute the Casimir energy in terms of determinants of single la
yer operators. Such formulae have been derived by other methods in the phy
sics literature and we will show that all these approaches give the same w
ell 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://researchseminars.org/talk/IAMP_seminars/117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giovanni Felder (ETH Zürich)
DTSTART:20221101T140000Z
DTEND:20221101T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/118
DESCRIPTION:Title: Boltzmann's billiard and table tennis\nby Giovanni Felder (ETH
Zürich) as part of One world IAMP mathematical physics seminar\n\n\nAbst
ract\nIn Boltzmann's billiard a particle moves in a half-plane subject to
a central force and is reflected elastically when it hits the boundary. Bo
ltzmann took the central force to be the sum of a gravitational inverse-sq
uare-law force and a centrifugal term proportional to the\ninverse cube of
the distance to the centre. He formulated the expectation that except for
special values of the parameters the system would be chaotic and would ob
ey his Ergodic Hypothesis. Recently Gallavotti and Jauslin showed that the
system is integrable if the\ncentrifugal term is omitted: it has a second
conserved quantity besides the energy. I will review this result and show
that this integrable Boltzmann system has the Poncelet property: if in a
level set of the conserved quantities a trajectory is periodic then all tr
ajectories on the level set are periodic. As for the classical Poncelet th
eorem on inscribed-circumscribed polygons in Jacobi's interpretation\, the
result relies on the theory of elliptic curves. I will also present some
work in progress with Misha Feigin on Boltzmann's table tennis\, the three
dimensional version of Boltzmann's integrable system\, and the relation t
o QRT maps on biquadratic plane curves.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Dimock (SUNY at Buffalo)
DTSTART:20220816T140000Z
DTEND:20220816T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/119
DESCRIPTION:Title: Ultraviolet Stability for Quantum Electrodynamics in d=3\nby J
onathan Dimock (SUNY at Buffalo) as part of One world IAMP mathematical ph
ysics seminar\n\n\nAbstract\nWe report on results for quantum electrodynam
ics on a finite\nvolume Euclidean spacetime in dimension $d=3$. The theory
is formulated as a\nfunctional integral on a fine toroidal lattice involv
ing both fermion fields and\nabelian gauge fields. The main result is that
\, after renormalization\, the partition\nfunction is bounded uniformly in
the lattice spacing. This is a first step toward\nthe construction of the
model. The result is obtained by renormalization group\nanalysis pioneere
d by Balaban. A single renormalization group transformation\ninvolves bloc
k averaging\, a split into large and small field regions\, and an identifi
cation of effective actions in the small field regions via cluster expansi
ons.\nThis leads to flow equations for the parameters of the theory. Renor
malization\nis accomplished by fine-tuning the initial conditions for thes
e equations. Large\nfield regions need no renormalization\, but are shown
to give a tiny contribution.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martin Fraas (UC Davis)
DTSTART:20220802T140000Z
DTEND:20220802T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/120
DESCRIPTION:Title: Projections\, parallel transport and adiabatic theory\nby Mart
in Fraas (UC Davis) as part of One world IAMP mathematical physics seminar
\n\n\nAbstract\nI will give an overview of adiabatic theory with the focus
on a geometric point of view. The talk will cover traditionally adiabatic
theory\, adiabatic theory in many-body systems\, and a recent work with W
. De Roeck and A. Elgart on the adiabatic theory for disordered systems.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anton Alekseev (University of Geneva)
DTSTART:20221115T140000Z
DTEND:20221115T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/121
DESCRIPTION:Title: Virasoro Hamiltonian spaces\nby Anton Alekseev (University of
Geneva) as part of One world IAMP mathematical physics seminar\n\n\nAbstra
ct\nIn this talk\, we consider Hamiltonian actions of the group of diffeom
orphisms of the circle. This is a semiclassical countepart of Virasoro alg
ebra actions in Conformal Field Theory. The main examples include Virasoro
coadjoint orbits (previously studied by Segal\, Kirillov\, Witten and oth
ers) and moduli spaces of hyperbolic metrics on surfaces with boundary. Ou
r study is motivated by recent progress in Jackiw-Teitelboim quantum gravi
ty. In particular\, we give mathematical interpretation of some 2D - 1D du
ality phenomena.\n\nThe talk is based on work in progress with Eckhard Mei
nrenken.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Avramidi (New Mexico Tech)
DTSTART:20221122T140000Z
DTEND:20221122T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/122
DESCRIPTION:Title: Spectral Asymptotics of Elliptic Operators on Manifolds\nby Iv
an Avramidi (New Mexico Tech) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nThe study of spectral properties of natural geom
etric elliptic partial differential operators acting on smooth sections of
vector bundles over Riemannian manifolds is a central theme in global ana
lysis\, differential geometry and mathematical physics. Instead of studyin
g the spectrum of a differential operator $L$ directly one usually studies
its spectral functions\, that is\, spectral traces of some functions of t
he operator\, such as the spectral zeta function $\\zeta(s)=\\Tr L^{-s}$ a
nd 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-co
mmutative geometry\, integrable systems and financial mathematics. We revi
ew some recent progress in the study of spectral asymptotics. We study mor
e general spectral functions\, such as $\\Tr f(tL)$\, that we call quantum
heat traces. Also\, we define new invariants of differential operators th
at depend not only on the their eigenvalues but also on the eigenfunctions
\, and\, therefore\, contain much more information about the geometry of t
he manifold. Furthermore\, we study some new invariants\, such as $\\Tr\\e
xp(-tL_+)\\exp(-sL_-)$\, that contain relative spectral information of two
differential operators. Finally we show how the convolution of the semigr
oups of two different operators can be computed by using purely algebraic
methods.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sinya Aoki (YITP\, Kyoto University)
DTSTART:20221213T140000Z
DTEND:20221213T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/123
DESCRIPTION:Title: Lattice QCD: Introduction\, results and challenges\nby Sinya A
oki (YITP\, Kyoto University) as part of One world IAMP mathematical physi
cs seminar\n\n\nAbstract\nLattice QCD is a non-perturbative definition of
QCD (Quantum ChromoDynamics) on a discrete spacetime.\nI first give a comp
rehensive review on lattice QCD from the continuum QCD to numerical simul
ations.\nAs a representative of lattice QCD investigations\, I introduce h
adron mass calculations including an extraction of a hadron mass from the
hadron propagator\, its quark mass dependence and its extrapolation 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 such as n
uclear forces\, starting from a definition of potentials in QCD to numeric
al results on scattering phase shifts.\nThroughout my talk\, I comment on
degrees of rigorousness of the lattice QCD method from time to time.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Razvan Gurau (Universität Heidelberg)
DTSTART:20221108T140000Z
DTEND:20221108T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/124
DESCRIPTION:Title: Melonic field theories\nby Razvan Gurau (Universität Heidelbe
rg) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\n
Like random matrices\, random tensors exhibit a 1/N expansion\, but their
large N limit is more amenable to analytic computations. In particular ten
sor field theories provide a new class of large N theories\, the so called
melonic theories. In this talk I will present an overview of recent resul
ts on such theories and discuss their implications.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Imbrie (University of Virginia)
DTSTART:20221206T140000Z
DTEND:20221206T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/125
DESCRIPTION:Title: On the Many-Body Localization Transition\nby John Imbrie (Univ
ersity 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) i
f 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\n2
016\, I showed that there is an MBL phase by constructing LIOMs at\nstrong
disorder (the proof depended on a certain assumption on level\nstatistics
). The nature of the transition out of the MBL phase has\nbeen a subject o
f study and conjecture. In recent work with\nMorningstar and Huse (PRB\, 2
020)\, we utilize a series of\napproximations to develop specific RG flow
equations. These are\nsimilar to the Kosterlitz-Thouless (KT) flow equatio
ns\, but there are\nimportant differences that place the MBL transition in
a new\nuniversality class.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Massimiliano Gubinelli (University of Oxford)
DTSTART:20221220T140000Z
DTEND:20221220T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/126
DESCRIPTION:Title: A stochastic analysis of EQFTs: the forward-backwards equation for
Grassmann measures\nby Massimiliano Gubinelli (University of Oxford)
as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nI wi
ll report on a research program to use ideas from stochastic analysis in t
he context of constructive quantum field theories. Stochastic analysis can
be summarized as the study of measures on path space via push-forward fro
m Gaussian measures. The basic example is the Ito map which sends Brownian
motion to a Markov diffusion process solution to a stochastic differentia
l equation. Parisi-Wu stochastic quantisation can be understood as a stoch
astic 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 Polchinski an
d which uses a forward-backwards stochastic differential equation. In orde
r to be able to give a full non-perturbative construction I will focus on
the case of Grassmann measures seen as instances of non-commutative random
fields.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jan Dereziński (University of Warsaw)
DTSTART:20230110T140000Z
DTEND:20230110T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/127
DESCRIPTION:Title: Dirac-Coulomb Hamiltonians\nby Jan Dereziński (University of
Warsaw) as part of One world IAMP mathematical physics seminar\n\n\nAbstra
ct\nI will discuss the theory of Dirac operators perturbed by the Coulomb
potential in an arbitrary dimension. These operators are interesting for s
everal reasons:\n\n– They have obvious applications to atomic physics.\n
\n– If one neglects the mass term\, they are formally homogeneous.\n\n
– Depending on the coupling constant and dimension\, they exhibit severa
l distinct scaling behaviors (or if you prefer the high energy jargon\, va
rious “renormalization group flows”).\n\n– Their definition involves
subtle boundary conditions.\n\n– They are exactly solvable in terms of
Whittaker functions.\n\nMy talk will be based on recent joint work with B
łażej Ruba.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/127/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amanda Young (Technical University of Munich)
DTSTART:20230307T140000Z
DTEND:20230307T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/128
DESCRIPTION:Title: A bulk gap in the presence of edge states for a truncated Haldane
pseudopotential\nby Amanda Young (Technical University of Munich) as p
art of One world IAMP mathematical physics seminar\n\n\nAbstract\nIn this
talk\, we discuss the bulk gap for a truncated\n1/3-filled Haldane pseudop
otential for the fractional quantum Hall\neffect in the cylinder geometry.
In the case of open boundary\nconditions\, a lower bound on the spectral
gap (which is uniform in the\nvolume and particle number) accurately refle
cts the presence of edge\nstates\, which do not persist into the bulk. A u
niform lower bound for\nthe Hamiltonian with periodic boundary conditions
is also obtain. Both\nof these bounds are proved by identifying invariant
subspaces to which\nspectral gap and ground state energy estimating method
s originally\ndeveloped for quantum spin Hamiltonians are applied. Customi
zing the gap\ntechnique to the invariant subspace\, however\, we are able
to avoid the\nedge states and establish a more precise estimate on the bul
k gap in the\ncase of periodic boundary conditions. The same approach can
also be\napplied to prove a bulk gap for the analogously truncated Haldane
\npseudopotential with maximal half filling\, which describes a strongly\n
correlated system of spinless bosons in a cylinder geometry. This is\nbase
d off joint work with S. Warzel.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lingrui Ge (University of California\, Irvine)
DTSTART:20230404T140000Z
DTEND:20230404T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/129
DESCRIPTION:Title: Multiplicative Jensen’s formula and quantitative global theory f
or ID quasiperiodic operators\nby Lingrui Ge (University of California
\, Irvine) as part of One world IAMP mathematical physics seminar\n\n\nAbs
tract\nWe prove multiplicative Jensen’s formula and establish quantitati
ve global theory for analytic one-frequency Schrodinger operators. We will
also discuss the motivations and further applications.\nThis is based on
a joint work with Jiangong You\, Svetlana Jitomirskaya and Qi Zhou.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Maes (KU Leuven)
DTSTART:20230221T140000Z
DTEND:20230221T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/130
DESCRIPTION:Title: Nonequilibrium extension of Third Law\nby Christian Maes (KU L
euven) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\nThe Nernst-Planck Postulate (Third Law of Thermodynamics stating that t
he entropy becomes zero at zero temperature) has a different status from t
he other Laws: it is not a consequence of the general structure of statis
tical thermodynamics\, it can fail\, and it does not carry a straightforwa
rd dynamic or kinetic derivation when it does hold. In this talk we consi
der the latter question\, by extending the Third Law to nonequilibrium jum
p processes. We give sufficient conditions in a Nonequilibrium Nernst The
orem\, that the operationally defined excess heat vanishes at absolute zer
o\, and from counter examples\, we understand that those conditions are we
ll on target. We give an example of a zero-temperature nonequilibrium tra
nsition where the heat capacity abruptly diverges as a function of the che
mical potential. The main ingredients in the proof are a formulation of t
he quasistatic relaxation between nonequilibrium steady conditions\,d a co
mbined application of the matrix tree and the matrix forest theorem.\n\nJo
int work with Faezeh Khodabandehlou and Karel Netocny.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/130/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Elgart (Virginia Tech)
DTSTART:20230207T140000Z
DTEND:20230207T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/131
DESCRIPTION:Title: Localization of the random XXZ spin chain in fixed energy interval
s\nby Alexander Elgart (Virginia Tech) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nA Schrödinger operator $H$ is know
n to exhibit quasi-locality: Matrix elements of analytic functions of $H$
decay exponentially away from the diagonal. Localization for a random Schr
ödinger operator can be expressed as an extension of this feature to Bore
l measurable functions with support in the region of localization.\n\n\nWe
show that the spin-$\\frac12$ XXZ random chain Hamiltonian $H_{XXZ}$ mani
fests a suitably defined notion of quasi-locality as well. We exploit this
property to prove that $H_{XXZ}$ exhibits localization in any fixed energ
y interval (expressed as quasi-locality for Borel measurable functions of
$H_{XXZ}$ with support in the energy interval). Localization is proved in
a nontrivial region of the parameter space\, which includes weak interact
ion and strong disorder regimes\, and is independent of the size of the sy
stem\, depending only on the energy interval.\n\n\nBased on a joint work w
ith Abel Klein\, https://arxiv.org/abs/2210.14873\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/131/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Hainzl (Mathematisches Institut der Universität Münche
n)
DTSTART:20230124T140000Z
DTEND:20230124T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/132
DESCRIPTION:Title: Correlation energy of an electron gas in the mean-field approximat
ion\nby Christian Hainzl (Mathematisches Institut der Universität Mü
nchen) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\nThe correlation energy of a high density fermionic Coulomb gas\, called
Jellium\, is expected to be given by the Gell-Mann Brueckner formula. I w
ill discuss an analogue of this formula for the mean-field regime. I prese
nt a rigorous upper bound established by variational methods in the case o
f Coulomb interaction. I will further review similar results for more regu
lar potentials\, which is meanwhile well understood for particles in a fix
ed box. The talk is based on joint work with Martin Christiansen and P. T.
Nam.\n
LOCATION:https://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:20260422T225925Z
UID:IAMP_seminars/133
DESCRIPTION:Title: Pseudo-gaps for random hopping models\nby Hermann Schulz-Balde
s (Friedrich-Alexander-Universitaet Erlangen-Nuernberg) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nFor one-dimensional ra
ndom Schrödinger operators\, the integrated density of states\nis known t
o be given in terms of the (averaged) rotation number of the Pr¨ufer phas
e\ndynamics. This paper develops a controlled perturbation theory for the
rotation number\naround an energy at which all the transfer matrices commu
te and are hyperbolic. Such\na hyperbolic critical energy appears in rando
m hopping models. The main result is a\nHölder continuity of the rotation
number at the critical energy that implies the existence\nof a pseudo-gap
. The proof uses renewal theory. The result is illustrated by numerics.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/133/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Toninelli (Univ. Paris Dauphine)
DTSTART:20230516T140000Z
DTEND:20230516T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/134
DESCRIPTION:Title: Bootstrap percolation and kinetically constrained models: universa
lity results\nby Cristina Toninelli (Univ. Paris Dauphine) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nRecent years ha
ve seen a great deal of progress in understanding the behavior of bootstra
p percolation (BP) models\, a particular class of monotone cellular automa
ta. In the initial configuration sites are occupied with probability p. Th
e evolution of BP occurs at discrete times: empty sites stay empty and occ
upied sites are emptied iff a certain model dependent neighborhood is alre
ady empty. In the Euclidean lattice there is now a complete understanding
of the large time evolution with a universality picture for the critical b
ehavior. Much less is known for their non-monotone stochastic counterpart\
, namely kinetically constrained models (KCM). In KCM each vertex is updat
ed independently at rate p (respectively 1-p) to occupied (respectively e
mpty) iff it could be emptied in the next step by the bootstrap model. In
the last two decades KCM have been the subject of intensive research both
in physics and mathematics literature. The main motivation is that\, for c
ertain choices of the constraints\, when p goes to zero KCM display some o
f the most striking features of the liquid/glass transition. Indeed\, they
were originally introduced in the 80's to support the free volume theorie
s and later on used as the simplest lattice models reproducing the dynamic
al facilitation scenario. In this seminar I will discuss some recent rigor
ous results on the characteristic time scales of KCM as p goes to zero as
well as the connection with the critical behavior of the corresponding BP
models.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Flora Koukiou (Cergy–Pontoise University)
DTSTART:20230530T140000Z
DTEND:20230530T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/135
DESCRIPTION:Title: Freezing and Entropy of the Log-correlated Random fields\nby F
lora Koukiou (Cergy–Pontoise University) as part of One world IAMP mathe
matical physics seminar\n\n\nAbstract\nFreezing is a concept that was int
roduced more than thirty years ago and has since been\nstudied in the cont
ext of statistical mechanics and\, more recently\, has been related to mul
tifractality and\nextreme value statistics.\nIn this talk\, after a short
survey\, we define freezing in relation to the behaviour of the entropy
of the Gibbs measures for several mean-field models.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scott Armstrong (New York University)
DTSTART:20230613T140000Z
DTEND:20230613T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/136
DESCRIPTION:Title: Anomalous diffusion for passive scalar equations by fractal homoge
nization\nby Scott Armstrong (New York University) as part of One worl
d IAMP mathematical physics seminar\n\n\nAbstract\nIn this talk I will des
cribe the main ideas in a recent joint work with Vlad Vicol. We construct
an explicit divergence-free vector field on the torus\, which is Holder co
ntinuous with exponent almost 1/3 in space and time\, such that the corres
ponding advection-diffusion equation admits anomalous diffusion\, for all
initial data\, along a subsequence of diffusivities tending to zero. The c
onstruction builds into the vector field a countable sequence of "active s
cales" which have resonances with the scalar\, resulting in a cascade of e
nergy moving to smaller scales. The proof is a renormalization scheme\, ba
sed on homogenization methods.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/136/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michał Wrochna (Cergy Paris University)
DTSTART:20230418T140000Z
DTEND:20230418T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/137
DESCRIPTION:Title: Thermodynamics of quantum fields on rotating black hole spacetimes
\nby Michał Wrochna (Cergy Paris University) as part of One world IAM
P mathematical physics seminar\n\n\nAbstract\nWhat is the final quantum st
ate arising from black hole collapse\, and what are its thermodynamical pr
operties? In somewhat idealized models like the Kerr metric\, the conjectu
ral candidate is the Unruh state. While it is not an equilibrium state\, a
symptotically one expects the occurrence of Hawking temperature. In this t
alk I will review recent results that give a rigorous definition and const
ruction based on scattering theory. While the case of bosonic fields on Ke
rr spacetime is still open\, it turns out that it is possible to prove man
y physical properties of the Unruh state for instance for massless fermion
s. The talk is based on joint work with Christian Gérard and Dietrich Hä
fner.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikita Nekrasov (Simons Center for Geometry and Physics)
DTSTART:20230502T140000Z
DTEND:20230502T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/138
DESCRIPTION:Title: Qouroboros: Quantum mechanics from supersymmetric quantum field th
eory\nby Nikita Nekrasov (Simons Center for Geometry and Physics) as p
art of One world IAMP mathematical physics seminar\n\n\nAbstract\nWavefunc
tions of the stationary states of some quantum mechanical systems can be e
xactly computed using supersymmetric gauge theory in dimension 4. I will e
xplain theory and practice of the method.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Huse (Princeton)
DTSTART:20230919T140000Z
DTEND:20230919T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/139
DESCRIPTION:Title: Many-body localization\nby David Huse (Princeton) as part of O
ne world IAMP mathematical physics seminar\n\n\nAbstract\nMany-body locali
zation (MBL) is Anderson localization of many interacting quantum\ndegrees
of freedom in highly-excited states at conditions that correspond to a no
nzero entropy\ndensity at thermal equilibrium. The opposite of MBL is ther
malization\, where the isolated\nquantum many-body system successfully act
s as a thermal bath for itself\, bringing all of its\nsmall subsystems to
thermal equilibrium with each other via the unitary quantum dynamics of\nt
he closed system. For finite systems with short-range interactions the tra
nsition from\nthermalization to MBL occurs in two stages as the interactio
ns are reduced: First is a smooth\ncrossover to a “glassy” prethermal
MBL regime\, where the thermalization time of a large\nsystem becomes extr
emely large but not infinite. Then\, at still weaker interaction is the\nd
ynamical phase transition in to the MBL phase\, which in many cases occurs
at a strength of\ninteractions that is so small that it is thermodynamica
lly insignificant in the limit of large\nsystems\, even though it has stro
ng long-time dynamical effects.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/139/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcello Porta (SISSA)
DTSTART:20230905T140000Z
DTEND:20230905T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/140
DESCRIPTION:Title: Universality of Transport in Many-Body Lattice Models\nby Marc
ello Porta (SISSA) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nIn this talk I will discuss rigorous results about the char
ge transport properties of gapless interacting fermionic lattice models\,
with a particular emphasys on the emergence of universality at the macrosc
opic scale. I will outline a strategy that has been used over the years to
compute response functions for a class of gapless models\, including one-
dimensional metals and two and three-dimensional semimetals. The approach
is based on the combination of: analytic continuation of real-time respons
e functions to imaginary times\; renormalization group analysis of imagina
ry-time correlations and resolution of the scaling limit\; lattice conserv
ation laws and Ward identities to prove universality of transport coeffici
ents. I will focus on the application to the edge response function of int
eracting 2d quantum Hall systems\, defined starting from the linear respon
se ansatz. In the last part of the talk\, I will discuss how the framework
can be used go beyond linear response\, for gapped systems at low tempera
tures.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius Lemm (University of Tübingen)
DTSTART:20230627T140000Z
DTEND:20230627T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/141
DESCRIPTION:Title: Light cones for open quantum systems\nby Marius Lemm (Universi
ty of Tübingen) as part of One world IAMP mathematical physics seminar\n\
n\nAbstract\nWe consider non-relativistic Markovian open quantum dynamics
(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 initial quant
um state is localized in space\, then any finite-energy part of the soluti
on of the von Neumann-Lindblad equation is approximately localized inside
an energy-dependent light cone. We also obtain an explicit upper bound on
the slope of this light cone (i.e.\, on the maximal speed). The general me
thod can be used to derive propagation bounds for a variety of other quant
um systems including Lieb-Robinson bounds for lattice bosons. Based on joi
nt works with S. Breteaux\, J. Faupin\, D.H. Ou Yang\, I.M. Sigal\, and J.
Zhang.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Horng-Tzer Yau (Harvard)
DTSTART:20231031T140000Z
DTEND:20231031T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/142
DESCRIPTION:Title: Spectral gap and two point function estimates for mean-field sp
in glass models\nby Horng-Tzer Yau (Harvard) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nIn this lecture\, we’ll re
view some recent results regarding spectral gaps and logarithmic Sobolev
inequality for Glauber dynamics of mean-field spin glass models. In part
icular\, we will present a method to prove that the spectral gap of the G
lauber dynamics is of order one at sufficiently high temperature. In addi
tion\, we will review certain estimates on two point functions for the S
K model satisfying a modified AT condition.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sourav Chatterjee (Stanford)
DTSTART:20231003T140000Z
DTEND:20231003T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/143
DESCRIPTION:Title: Spin glass phase in the Edwards-Anderson model at zero temperature
\nby Sourav Chatterjee (Stanford) as part of One world IAMP mathematic
al physics seminar\n\n\nAbstract\nWhile the analysis of mean-field spin gl
ass 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://researchseminars.org/talk/IAMP_seminars/143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alberto Cattaneo (University of Zurich)
DTSTART:20231017T140000Z
DTEND:20231017T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/144
DESCRIPTION:Title: A cohomological view of quantum field theory\nby Alberto Catta
neo (University of Zurich) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nI will review the Batalin–Vilkovisky formalism an
d its\ncognates which present classical and quantum field theory via a\nfl
exible formalism in which spaces of fields are presented as\ncomplexes who
se cohomology returns the physical content. Different but\nequivalent comp
lexes may be used\, which turns out to be important\nconceptuallly and in
practice. Examples will be discussed.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/144/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nguyen Viet Dang (Sorbonne University)
DTSTART:20231114T140000Z
DTEND:20231114T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/145
DESCRIPTION:Title: The Phi43 measure on Riemannian manifolds\nby Nguyen Viet Dang
(Sorbonne University) as part of One world IAMP mathematical physics semi
nar\n\n\nAbstract\nI will describe a joint work with Bailleul\, Ferdinand
and To where we construct the $\\phi^4_3$ quantum field theory measure on
compact Riemannian 3-manifolds\, as invariant measure of some stochastic p
artial differential equation\, I will try to motivate the approach and sho
w many examples. This gives an example of nonperturbative\, interacting\,
non topological quantum field theory constructed on 3 manifolds.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Torben Krüger (Erlangen)
DTSTART:20231212T140000Z
DTEND:20231212T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/146
DESCRIPTION:Title: Merging Singularity in the Normal Matrix Model\nby Torben Krü
ger (Erlangen) as part of One world IAMP mathematical physics seminar\n\n\
nAbstract\nThe two-dimensional one-component plasma is a particle system i
n the plane with long-range logarithmic interactions. At a specific temper
ature the system is equivalent to the eigenvalue ensemble of a normal rand
om matrix model. In equilibrium the particles form droplets when placed in
an external potential. Using the Riemann-Hilbert approach we determine th
e local statistical behaviour of the particles at the merging point of dro
plets and observe an anisotropic scaling behaviour with particles being mu
ch further apart in the direction of merging than the perpendicular direct
ion\, effectively generating a one dimensional particle system. Very close
to the point of merger this leads to correlations described by the Painle
ve II kernel that is also present in certain unitary matrix ensembles. Fur
thermore\, in the vicinity of the singularity sine kernel statistics\, Gin
ibre edge and bulk statistics\, as well as the local statistics of a Coulo
mb gas confined to a small strip are observed. Our comprehensive descripti
on of the merging singularity lends support to the conjecture that the hie
rarchy of local particle statistics at singularities of the particle densi
ty within two-dimensional Coulomb gases can be characterised in terms of t
he corresponding hierarchy for one-dimensional invariant ensembles. \n\n
This is joint work with Meng Yang and Seung-Yeop Lee\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei-Min Wang (Shanghai / CNRS)
DTSTART:20240206T140000Z
DTEND:20240206T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/147
DESCRIPTION:Title: On the dynamics of nonlinear random and quasi-periodic systems
\nby Wei-Min Wang (Shanghai / CNRS) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nWe discuss time evolution of nonline
ar random and quasi-periodic systems and\nelaborate on their similarities.
Examples of such systems include the nonlinear random \nand the nonlinear
quasi-periodic Schr\\"odinger equations on the lattice. These problems \n
are related to and are partly motivated by many body localization.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Charles Newman (NYU -- Courant)
DTSTART:20240109T140000Z
DTEND:20240109T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/148
DESCRIPTION:Title: Brownian Excursions\, Ising Models and the Riemann Hypothesis -- P
ossible Connections\nby Charles Newman (NYU -- Courant) as part of One
world IAMP mathematical physics seminar\n\n\nAbstract\nThe distribution o
f the maximum of a Brownian excursion (BE)\,\nknown explicitly since 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 R
iemann Hypothesis would follow from the 1952\ntheorem of Lee and Yang abou
t zeros of\nIM partition functions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sebastien Ott (EPFL)
DTSTART:20231128T140000Z
DTEND:20231128T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/149
DESCRIPTION:Title: Asymptotic expansion for classical O(N) models\nby Sebastien O
tt (EPFL) as part of One world IAMP mathematical physics seminar\n\n\nAbst
ract\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) vectorial
GFF on the lattice. As a result\, one expects that it is possible to extra
ct precise informations about many observables from the GFF. A first resul
t going in this direction is to establish that one can expand quantities s
uch as the spontaneous magnetisation in Taylor series (in the temperature)
\, and that the coefficients of this series are the one obtained by formal
power series expansion.\nThis was acheived in 1981 by Bricmont\, Fontaine
\, Lebowitz\, Lieb\, and Spencer in the abelian case of the XY (O(2)) mode
l\, using a regularized version of Gaussian integration by part and infrar
ed bounds coming from reflection positivity of the model. I will briefly r
eview their approach\, and will present an extension to general N in dimen
sion 3 and higher\, highlighting what are the requiered new inputs.\nBased
on joint work with A.Giuliani\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rainer Verch (Leipzig)
DTSTART:20240305T140000Z
DTEND:20240305T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/150
DESCRIPTION:Title: Moving away from equilibrium\nby Rainer Verch (Leipzig) as par
t of One world IAMP mathematical physics seminar\n\n\nAbstract\nThe semina
r takes up on several aspects related to the Unruh effect. \nIn a nutshell
\,\n a mathematically rigorous treatment of the Unruh effect by de Biévr
e \nand Merkli has shown\n that a quantum mechanical\, finite-energy leve
l "detector" system \nwhich moves with constant\n acceleration with respe
ct to an inertial system\, and is locally \ncoupled to a quantum field\n
in the inertial vacuum state\, will asymptotically for large times \nappro
ximate a Gibbs (thermal\n equilibrium) state. In a new work with A.G. Pas
segger\, we show that \nthe behaviour of such\n a detector system is quit
e different if it moves with constant \nvelocity with respect to\n an ine
rtial system in which a quantum field is in a KMS state\, and \nto which t
he 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 respect\n t
o different inertial frames are disjoint (belong to inequivalent \nfolia o
f states) if they fulfill\n a suitable clustering condition. The quantize
d free scalar field is \nan example where the conditions\n are fulfilled.
Put differently\, Lorentz symmetry is broken (not \nunitarily implementab
le) in\n quantum field theory in inertial thermal (KMS) representations.
\n(This seems to belong to "general wisdom"\,\n but appears to have 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 th
ermal \nbackground of a quantum field\n in an inertial KMS state\, will n
ot asymptotically thermalize - at \nleast the return to equilibrium\n arg
uments are not applicable in this context because of the broken \nLorentz
symmetry in inertial\n KMS states. We also argue that this corroborates t
he view expressed \nby D. Buchholz and R. Verch\, and others\,\n that 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 conversion
of work to heat \nthrough the coupling of the\n detector to the quantum f
ield and the externally driven motion of \nthe detector.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/150/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claude-Alain Pillet (Toulon)
DTSTART:20240319T140000Z
DTEND:20240319T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/151
DESCRIPTION:Title: Adiabatic Time Evolution and Quasi-Static Processes in Translation
-Invariant Quantum Systems\nby Claude-Alain Pillet (Toulon) as part of
One world IAMP mathematical physics seminar\n\n\nAbstract\nWe study the s
lowly varying\, non-autonomous dynamics of a translation-invariant quantum
spin system on the lattice Z^d . This system is assumed to be initially i
n thermal equilibrium\, and we consider realizations of quasi-static proce
sses in the adiabatic limit. By combining the Gibbs variational principle
with the notion of quantum weak Gibbs states\, we establish a number of ge
neral structural results regarding such realizations. In particular\, we s
how that such a quasi-static process is incompatible with the property of
approach to\nequilibrium as discussed by V. Jaksic in his talk on March 22
\, 2022.\n\nThis is a joint work with V. Jaksic and C. Tauber\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/151/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yoh Tanimoto (Tor Vergata)
DTSTART:20240123T140000Z
DTEND:20240123T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/152
DESCRIPTION:Title: Wightman fields for two-dimensional conformal field theory\nby
Yoh Tanimoto (Tor Vergata) as part of One world IAMP mathematical physics
seminar\n\n\nAbstract\nFor a class of two-dimensional full conformal fiel
d theory\, we construct\nWightman fields generating the whole theory. The
construction is based\non non-local charged primary fields that intertwine
superselection\nsectors of the chiral components. We discuss the correspo
nding Schwinger\nfunctions that should satisfy the Osterwalder-Schrader ax
ioms and\nrelations with possibly massive models by the perturbation of th
e\nspacetime symmetry.\n(joint with M.S. Adamo\, L. Giorgetti\, C. Jäkel
and Y. Moriwaki)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/152/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kasia Rejzner (York)
DTSTART:20240416T140000Z
DTEND:20240416T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/153
DESCRIPTION:Title: Renormalisation of gauge theories in perturbative algebraic quantu
m field theory\nby Kasia Rejzner (York) as part of One world IAMP math
ematical physics seminar\n\n\nAbstract\nIn this talk I will briefly introd
uce the framework of\nperturbative algebraic quantum field theory (pAQFT)
and explain how it\ncan be used in quantisation of gauge theories. This re
quires methods\nfrom functional analysis as well as homological algebra. S
ome new\ndevelopments in this area involve treatment of theories on manifo
lds\nwith boundary\, including the "boundary at infinity." The latter case
\nallows the discussion of asymptotic symmetries\, e.g. in quantum\nelectr
odynamics.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/153/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Stottmeister (Hannover)
DTSTART:20240220T140000Z
DTEND:20240220T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/154
DESCRIPTION:Title: Embezzlement of entanglement\, quantum fields\, and the classifica
tion of von Neumann algebras\nby Alexander Stottmeister (Hannover) as
part of One world IAMP mathematical physics seminar\n\n\nAbstract\nWe disc
uss the embezzlement of entanglement in the setting of von Neumann algebra
s and its relation to the classification of the latter\, as well as its ap
plication to relativistic quantum field theory. Embezzlement (of entanglem
ent)\, introduced by van Dam and Hayden\, denotes the task of producing an
y entangled state to arbitrary precision from a shared entangled resource
state\, the embezzling state\, using local operations without communicatio
n while perturbing the resource arbitrarily little. \nWe show that Connes'
classification of type III von Neumann algebras can be given a quantitati
ve operational interpretation in terms of embezzlement. In particular\, th
is quantification implies that all type III factors\, apart from some type
III_0 factors\, host embezzling states. In contrast\, semifinite factors
(type I or II) cannot host embezzling states. \nSpecifically\, type III_1
factors are characterized as "universal embezzlers“\, meaning every norm
al state is embezzling. The latter observation provides a simple explanati
on as to why relativistic quantum field theories maximally violate Bell in
equalities.\nOur results follow from a one-to-one correspondence between e
mbezzling states and invariant states on the flow of weights.\n\nThis is j
oint work with Lauritz van Luijk\, Reinhard F. Werner\, and Henrik Wilming
.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/154/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aernout van Enter (Groningen)
DTSTART:20240430T140000Z
DTEND:20240430T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/155
DESCRIPTION:Title: Dyson models: One-sided and two-sided aspects\nby Aernout van
Enter (Groningen) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nI will discuss Dyson models\, long-range one-dimensional Isi
ng spin systems with ferromagnetic pair interactions.\nI first will discus
s how they provide an example for non-equivalence of one-sided and two-sid
ed regularity properties.\nThe switching between one-sided and two-sided
descriptions lies at the base of Thermodynamic Formalism\, which describe
s various Dynamical Systems as one-dimensional statistical mechanics model
s\, usually with fast decaying interactions..\nIn particular at low temper
atures there can be differences in continuity properties between a measu
re's one-sided and two-sided conditional probabilities. Gibbs measures f
or summable interactions can be characterised by the continuity of their t
wo-sided (from both left and right) conditional probabilities\, The one-s
ided analogue\, where a spin depends continuously on the left only (the p
ast)\, forms the class of g-measures. It was known before that a g-measu
re need not be a Gibbs measure. We show the opposite\, that a Gibbs measur
e for a summable interaction\, and in particular for a low-temperature Dy
son interaction\, can fail to be a g-measure.\n\nIn a somewhat different
usage\, one-sided versus two-sided systems describes models on a half-li
ne as compared with the model on the whole line.\nOne can consider the m
odel on the whole line as a model on two half-lines with a coupling term b
etween the half-lines.\nProperties of this coupling term\, connecting eith
er ordered or disordered half-lines\, such as its boundedness\, and integ
rability\, explain the properties of the "metastates" -- the distributi
on over limit states- of the model with random boundary conditions at low
temperatures.\nAlso they explain the continuity\, or the lack thereof\, o
f the eigenfunctions of Ruelle transfer operators at high temperatures.\nC
ontinuity of these eigenfunctions is a sufficient\, but not necessary\, co
ndition for continuity of the one-sided conditional probabilities. \nWe s
how that in certain circumstances the Radon-Nikodym density on the half-li
ne\, between coupled and decoupled Gibbs measures -- which is equal to th
e transfer operator eigenfunction--\, can have stronger regularity propert
ies than the analogous Radon-Nikodym density on the whole line.\n\nThe ta
lk is based on joint works with Rodrigo Bissacot\, Eric Endo\, Roberto F
ernández\, Arnaud Le Ny\, Mirmukhsin Makhmudov and Evgeny Verbitskiy\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephan De Bièvre (Lille)
DTSTART:20240618T140000Z
DTEND:20240618T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/156
DESCRIPTION:Title: Assessing optical nonclassicality with the quadrature coherence sc
ale\nby Stephan De Bièvre (Lille) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nIn quantum optics\, a state is said to
be ``classical’’ if it is a mixture of coherent states. Equivalently\,
such states have a positive Glauber-Sudarshan P-function. It is a longsta
nding problem in quantum optics\, that has attracted renewed attention in
the context of quantum information theory\, to efficiently identify/charac
erize the convex set of all such states. After reviewing some of the histo
ry of this problem\, we shall in this talk present the ``quadrature cohere
nce scale’’\, which provides a measure of non-classicality (in the abo
ve sense)\, and detail some of its merits. We will further briefly discuss
the analogous problems of determining the set of all Wigner-positive stat
es and of all Kirkwood-Dirac positive states.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noé Cuneo (LPSM)
DTSTART:20240402T140000Z
DTEND:20240402T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/157
DESCRIPTION:Title: Large deviations of return times and related entropy estimators on
shift spaces\nby Noé Cuneo (LPSM) as part of One world IAMP mathemat
ical physics seminar\n\n\nAbstract\nThe study of return times in dynamical
systems has a long history\, and their role as entropy estimators is well
established. While considerable attention has been devoted to the corresp
onding Law of Large Numbers\, Central Limit Theorem and pressure function
in the literature\, surprisingly little was known about their large deviat
ions. In fact\, only local versions of the Large Deviation Principle (LDP)
were obtained\, under some rather restrictive assumptions. I will talk ab
out a recent work in collaboration with Renaud Raquépas (arXiv:2306.05277
\, to appear in Commun. Math. Phys.)\, where we prove that return times sa
tisfy the full LDP for a large class of invariant measures on shift spaces
. Our assumptions cover in particular irreducible Markov chains\, equilibr
ium measures for Bowen-regular potentials\, invariant Gibbs states for abs
olutely summable interactions in statistical mechanics (including in the p
hase-transition regime)\, and some repeated quantum measurement processes.
As we will see in a striking example\, the rate function governing the LD
P can be nonconvex.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/157/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roderich Tumulka (Tübingen)
DTSTART:20240514T140000Z
DTEND:20240514T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/158
DESCRIPTION:Title: Time evolution of closed macroscopic quantum systems towards therm
al equilibrium\nby Roderich Tumulka (Tübingen) as part of One world I
AMP mathematical physics seminar\n\n\nAbstract\nSuppose we make a hot bric
k 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 hotter to
the cooler until they reach the same\ntemperature. This example illustrate
s the sense in which an isolated\,\nmacroscopic quantum system in a pure s
tate will approach thermal\nequilibrium. Here\, different macro-states cor
respond to mutually\northogonal subspaces of Hilbert space\, each of very
high dimension\,\nthermal equilibrium to one of these subspaces\, and entr
opy to the\nlogarithm of the dimension. I will describe results concerning
the\nunitary time evolution of such systems towards thermal equilibrium\,
the\nrole played by a version of the eigenstate thermalization hypothesis
\,\nand some open questions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/158/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Niels Benedikter (Milan)
DTSTART:20240604T140000Z
DTEND:20240604T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/159
DESCRIPTION:Title: Bosonization of Large Systems of Interacting Fermions\nby Niel
s Benedikter (Milan) as part of One world IAMP mathematical physics semina
r\n\n\nAbstract\nThe behavior of electrons in a metal presents a wide vari
ety of emergent behavior including a number of phase transitions. The mean
-field scaling limit acts as a simplified model capturing part of this com
plexity. In this limit\, results going beyond the precision of Hartree-Foc
k theory have recently been obtained by bosonization methods. I will revie
w the expansion of the ground state energy and present results extending t
o the dynamics and momentum distribution of excitations.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Wald (Chicago)
DTSTART:20240730T140000Z
DTEND:20240730T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/160
DESCRIPTION:Title: The Memory Effect and Infrared Divergences\nby Robert Wald (Ch
icago) as part of One world IAMP mathematical physics seminar\n\n\nAbstrac
t\nThe "memory effect" is the permanent relative displacement of test part
icles after the passage of gravitational radiation. It is associated with
both the propagation of massive bodies out to timelike infinity ("ordinary
memory") or the propagation of radiation out to null infinity ("null memo
ry"). The memory effect can be characterized by the failure of the shear t
ensor at order 1/r to return to zero at late times\, even though it is "pu
re gauge." Closely analogous effects occur in electromagnetism\, where 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 infrared div
ergences (i.e.\, infinite numbers of "soft" gravitons/photons) in the quan
tum field theory description if one attempts to describe these states as v
ectors in the usual Fock Hilbert space representation. To obtain a mathema
tically sensible quantum scattering theory\, one must allow states with no
nvanishing memory in the "in" and "out" Hilbert spaces. An elegant solutio
n to this problem in massive quantum electrodynamics was given by Kulish a
nd Fadeev\, who constructed a Hilbert space of incoming/outgoing charged p
article states that are "dressed" with radiative fields of corresponding m
emory\, so as to yield vanishing large gauge charges at spatial infinity.
However\, we show that this type of construction fails in quantum gravity.
The primary underlying reason is that the ``dressing'' contributes to nul
l memory\, thereby invalidating the construction of eigenstates of large g
auge charges. In quantum gravity\, there does not appear to be any choice
of (separable) Hilbert space of incoming/outgoing states that can accommod
ate all scattering states.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/160/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Mitrouskas (ISTA)
DTSTART:20240924T140000Z
DTEND:20240924T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/161
DESCRIPTION:Title: Low-Energy Properties of the Strongly Coupled Polaron\nby Davi
d Mitrouskas (ISTA) as part of One world IAMP mathematical physics seminar
\n\n\nAbstract\nThe Fröhlich Hamiltonian models an electron interacting w
ith a polarizable medium\, described by a nonrelativistic quantum field. I
n the strong coupling regime\, the ground state energy of the quantum mode
l is known to converge to that of its semiclassical counterpart\, where th
e field is treated classically. This talk will review recent results on th
e low-energy properties of the Fröhlich Hamiltonian in this regime. The d
iscussion includes an asymptotic series expansion for the eigenvalues in t
he confined model\, and the existence of excited bound states in the trans
lation-invariant model at fixed total momentum.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/161/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sky Cao (MIT)
DTSTART:20240910T140000Z
DTEND:20240910T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/162
DESCRIPTION:Title: Global well-posedness of stochastic Abelian-Higgs in two dimension
s\nby Sky Cao (MIT) as part of One world IAMP mathematical physics sem
inar\n\n\nAbstract\nThere has been much recent progress on the local solut
ion theory for geometric singular SPDEs. However\, the global theory is st
ill largely open. In my talk\, I will discuss the global well-posedness of
the stochastic Abelian-Higgs model in two dimensions\, which is a geometr
ic singular SPDE arising from gauge theory. The proof is based on a new co
variant approach\, which consists of two parts: First\, we introduce covar
iant stochastic objects\, which are controlled using covariant heat kernel
estimates. Second\, we control nonlinear remainders using a covariant mon
otonicity formula\, which is inspired by earlier work of Hamilton. Joint w
ork with Bjoern Bringmann.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/162/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simon Becker (ETH Zürich)
DTSTART:20241022T140000Z
DTEND:20241022T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/163
DESCRIPTION:Title: Magic moire materials\nby Simon Becker (ETH Zürich) as part o
f One world IAMP mathematical physics seminar\n\n\nAbstract\nI will review
recent advancements in the field of twistronics. \nTwistronics investigat
es how varying the angle between layers of two-dimensional materials can s
ignificantly alter their electrical properties.\nNotably\, twisted bilayer
graphene exhibits a broad spectrum of different strongly correlated phase
s of matter\, ranging from non-conductive to superconductive\, depending o
n the specific twist angle between its layers. \nThese remarkable effects
are observed at particular angles known as magic angles.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Angela Capel Cuevas (Cambridge)
DTSTART:20241105T140000Z
DTEND:20241105T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/164
DESCRIPTION:Title: Rapid thermalisation of quantum dissipative many-body systems\
nby Angela Capel Cuevas (Cambridge) as part of One world IAMP mathematical
physics seminar\n\n\nAbstract\nQuantum systems typically reach thermal eq
uilibrium when in weak contact with a large external bath. Understanding t
he speed of this thermalisation is a challenging problem\, especially in t
he context of quantum many-body systems where direct calculations are intr
actable. The usual way of bounding the speed of this process is by estimat
ing the spectral gap of the dissipative generator\, but this does not alwa
ys yield a reasonable estimate for the thermalisation time. When the syste
m satisfies instead a modified logarithmic Sobolev inequality (MLSI)\, th
e thermalisation time is at most logarithmic in the system size\, yielding
wide-ranging applications to the study of many-body in and out-of-equilib
rium quantum systems\, such as stability against local perturbations (in t
he generator)\, efficient preparation of Gibbs states (the equilibria of t
hese processes)\, etc.\n\nIn this talk\, I will present an overview on a s
trategy to prove that a system satisfies a MLSI provided that correlations
decay sufficiently fast between spatially separated regions on the Gibbs
state of a local\, commuting Hamiltonian. This will allow us to conclude t
hat any Davies or Schmidt dissipative generator converging to a 2-local\,
commuting Hamiltonian at high-enough temperature thermalises in a time log
arithmic in the system size.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/164/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wojciech De Roeck (KU Leuven)
DTSTART:20241203T140000Z
DTEND:20241203T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/166
DESCRIPTION:Title: Absence of Normal Heat Conduction in Strongly Disordered Interacti
ng Quantum Chains\nby Wojciech De Roeck (KU Leuven) as part of One wor
ld IAMP mathematical physics seminar\n\n\nAbstract\nWe prove that in stron
gly disordered\, interacting\, quantum chains\, the conductance of a chain
of length L vanishes faster than 1/L. This means that transport is anomal
ous in such chains. This phenomenon was first claimed in 2005 in seminal w
ork by Basko\, Aleiner and Altshuler and a pioneering mathematical treatme
nt was given by Imbrie in 2014. The proof largely relies on proving a s
tronger property for some rare intervals on the chain\, whose location dep
ends on the realization of disorder. This stronger property is called 'Ma
ny-Body Localization' and it is of independent interest.\n(joint work with
Lydia Giacomin\, Francois Huveneers\, Oskar Prosniak)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/166/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wendelin Werner (Cambridge)
DTSTART:20250114T140000Z
DTEND:20250114T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/167
DESCRIPTION:Title: Percolation of loops and the Gaussian Free Field\nby Wendelin
Werner (Cambridge) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nThe Gaussian Free Field and its correlation structure are\n
closely related to questions about percolation in a gas of independent\nBr
ownian loops (the loop-soup). We will discuss recent and new results\nabou
t this connection\, and what we can learn about the nature of these\nunder
lying percolation clusters depending on the dimension of space. We\nwill a
lso mention how this relation can be extended to models for\nlocally inter
acting loops.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Naoto Shiraishi (Tokyo)
DTSTART:20250128T140000Z
DTEND:20250128T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/168
DESCRIPTION:Title: Proving non-integrability of quantum spin systems\nby Naoto Sh
iraishi (Tokyo) as part of One world IAMP mathematical physics seminar\n\n
\nAbstract\nIn mathematical physics\, integrable systems have been studied
intensively\, and various quantum spin models have been revealed to be in
tegrable. In contrast\, few studies in mathematical physics have tackled q
uantum non-integrability. Here we characterize non-integrability by the ab
sence of local conserved quantity as a working definition. The hardness of
analyzing non-integrability comes from the fact that there is no good met
hod to treat all possible local conserved quantities. For this reason\, no
n-integrability is sometimes even considered to be out of the scope of rig
orous mathematical physics.\n\nContrary to this pessimistic view\, a metho
d to prove quantum non-integrability was recently discovered. In this semi
nar\, I will talk about the recent progress in proving non-integrability o
f quantum spin systems. In the first part\, I will provide the proof of no
n-integrability of S=1/2 XYZ chain with z magnetic field\, where the basic
proof ideas and techniques can be seen. In the second part\, I will prove
the classification of integrability/non-integrability for all S=1/2 spin
chains with symmetric nearest-neighbor interaction. This classification th
eorem confirms that there is no missing integrable models in this class. M
y talk is based on a series of papers including collaborated works with M.
Yamaguchi and Y. Chiba.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/168/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Annalisa Panati (Toulon)
DTSTART:20250211T140000Z
DTEND:20250211T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/169
DESCRIPTION:Title: Entropic fluctuations in quantum two-time measurement framework\nby Annalisa Panati (Toulon) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nNon-equilibrium statistical mechanics has seen
some impressive developments in the last three decades\, since the ground-
breaking formulation of the transient and steady entropic Fluctuation Rela
tions (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 s
till an ongoing effort. Kurchan and Hal Tasaki's seminal works (2000) show
ed quantum formulation of the transient version of FR is possible by intro
ducing the two-time measurement framework.\n\nIn this talk\, we present so
me results in a recent series of papers\, where we attempt to introduce a
quantum equivalent of steady entropic functional and compare it to the tra
nsient version for open quantum system.\n\nWe consider both the case of id
ealised direct measurement on the reservoirs and experimentally accessible
indirect measurement through coupling with an ancilla. We analyse in part
icular stability with respect to the initial state.\nIn order to deal with
the thermodynamic limit and to have general results\, we use methods of $
C^*$- algebras and modular theory.\n\n(Joint work with T. Benoist\, L. Bru
neau\, V. Jakšić\, C.A. Pillet)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/169/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ko Sanders (FAU Erlangen-Nürnberg)
DTSTART:20250304T140000Z
DTEND:20250304T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/170
DESCRIPTION:Title: Entanglement and separable states in relativistic QFT\nby Ko S
anders (FAU Erlangen-Nürnberg) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nIn quantum physics\, entanglement is the pheno
menon of primary interest. It defines the distinction to classical physics
\, allows for remarkable experiments and raises fundamental questions abou
t nature. This is all the more so in relativistic quantum field theories (
QFTs)\, where the dependence of entanglement on the localisation in spacet
ime can be investigated. In particular\, one can consider the spacetime de
pendence of the entanglement entropy\, which measures the amount of entang
lement in a state by comparing it to "nearby" separable states. In this ta
lk I will start with a review of the history and basics of entanglement an
d I will describe some results concerning the entanglement entropy\, keepn
ig 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://researchseminars.org/talk/IAMP_seminars/170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sven Bachmann (UBC)
DTSTART:20250401T140000Z
DTEND:20250401T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/171
DESCRIPTION:Title: Tensor categories and quantization for the quantum Hall effect
\nby Sven Bachmann (UBC) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nThe aim of this talk is to show that quantization of
the Hall conductance in the infinite plane geometry follows from the finit
eness of the number of the superselection sectors of microscopic quantum l
attice systems. These are equivalence classes of certain representations o
f the algebra of observables\, which correspond physically to types of qua
si-particle excitations. I will review aspects of this representation theo
ry\, show how it is naturally described in terms of a certain category\, a
nd explain how the Hall conductance appears within this framework. This is
joint work with M. Corbelli\, M. Fraas and Y. Ogata.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/171/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Schiavina (University of Pavia)
DTSTART:20250318T140000Z
DTEND:20250318T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/172
DESCRIPTION:Title: Superselection sectors from Hamiltonian reduction\nby Michele
Schiavina (University of Pavia) as part of One world IAMP mathematical phy
sics seminar\n\n\nAbstract\nI will discuss the Hamiltonian formulation of
local field theories on manifolds with corners in the particular\, yet com
mon\, case in which they admit an equivariant momentum map. In the presen
ce of corners\, the momentum map naturally splits into a part encoding “
Cauchy data” or constraints\, and a part encoding the “flux” across
the corner.\n\nThis decomposition plays an important role in the construct
ion of the reduced phase space\, which is conveniently handled via symplec
tic reduction by stages\, adapted for the occasion to local group actions.
\n\nThe output of this analysis are natural Poisson structures associated
to corner submanifolds\, leading to the concept of (classical) flux super
selection sectors as their symplectic leaves\, and providing a roadmap to
quantum superselection.\n\nThis general approach has modern applications r
anging from electrodynamics to gravitation\, where factorisation formulas
akin to the Peter-Weyl theorem and Verlinde formula are expected\, owing t
o the (degenerate) Poisson structure on reduced phase spaces.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/172/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Deuchert (Virginia Tech)
DTSTART:20250415T140000Z
DTEND:20250415T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/173
DESCRIPTION:Title: The Gibbs state of the mean-field Bose gas\nby Andreas Deucher
t (Virginia Tech) as part of One world IAMP mathematical physics seminar\n
\n\nAbstract\nWe consider the homogeneous mean-field Bose gas at temperatu
res proportional to\nthe critical temperature of its Bose-Einstein condens
ation phase transition.\nOur main result is a trace-norm approximation of
the grand canonical Gibbs\nstate in terms of a reference state\, which is
given by a convex combination of\nproducts of coherent states and Gibbs st
ates associated with certain\ntemperature-dependent Bogoliubov Hamiltonian
s. The convex combination is\nexpressed as an integral over a Gibbs distri
bution of a one-mode phi-4-theory\ndescribing the condensate. We interpret
this result as a justification of\nBogoliubov theory at positive temperat
ure. Further results derived from the\nnorm approximation include various
limiting distributions for the number of\nparticles in the condensate\, as
well as precise formulas for the one- and\ntwo-particle density matrices
of the Gibbs state. Key ingredients of our proof\,\nwhich are of independe
nt interest\, include two novel abstract correlation\ninequalities. The pr
oof of one of them is based on an application of an\ninfinite-dimensional
version of Stahl's theorem.\n
\nThis is joint work with Phan Thành Nam
and Marcin Napiórkowski\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zaher Hani (Michigan)
DTSTART:20250527T140000Z
DTEND:20250527T150000Z
DTSTAMP:20260422T225925Z
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://researchseminars.org/talk/IAMP_seminars/174/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carolyn Zhang (Harvard)
DTSTART:20250624T140000Z
DTEND:20250624T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/175
DESCRIPTION:Title: Anomaly-free symmetries with obstructions to gauging and onsiteabi
lity\nby Carolyn Zhang (Harvard) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nDespite the long history of the study of
't Hooft anomalies and their broad applications\, there is still a lack of
consensus on the precise definition of 't Hooft anomalies. Two common def
initions are 1) obstructions to gauging a symmetry and 2) obstructions to
a trivially symmetric state. It is often believed that these two definitio
ns are equivalent\, and indeed they were recently proven to be equivalent
in 1+1D spin chains with finite\, internal\, unitary symmetries. We show t
hat this is not the case in 2+1D. In particular\, we present an index $\\
omega\\in H^2(G\,Q^{\\times})$ for 0-form finite\, internal\, unitary symm
etries where $Q^{\\times}$ is the group of rational numbers under multipli
cation. We show that symmetries with nontrivial $\\omega$ cannot be gauged
or made on-site\, but nevertheless admit trivially symmetric product stat
es with symmetric commuting parent Hamiltonians.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/175/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Fresta (Bonn)
DTSTART:20250708T140000Z
DTEND:20250708T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/176
DESCRIPTION:Title: Local Dynamics of Extended Fermi Gases at High Density\nby Luc
a Fresta (Bonn) as part of One world IAMP mathematical physics seminar\n\n
\nAbstract\nIn this talk\, I will discuss the quantum evolution of extende
d many-body\npseudo-relativistic Fermi gases in a high-density\, semiclass
ical scaling\nregime. I will present a result that establishes convergence
to the Hartree\ndynamics in the sense of expectation values of local obse
rvables\, with a\nconvergence rate depending only on the density. The resu
lt applies to\ninitial data describing equilibrium states confined in arbi
trarily large\ndomains\, under the assumption of suitable local Weyl-type
estimates. The\nproof is based on approximating the initial data by low-te
mperature\nquasi-free states\, for which one can establish a strong local
semiclassical\nstructure\, capturing spatial decay of correlations. This s
tructure plays a\nkey role in controlling the local growth of fluctuations
under the many-body\ndynamics. Based on joint work with Marcello Porta (S
ISSA) and Benjamin\nSchlein (Zürich).\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/176/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Leblé (CNRS)
DTSTART:20250513T140000Z
DTEND:20250513T150000Z
DTSTAMP:20260422T225925Z
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 seminar\n\n\
nAbstract\nThe two-dimensional one-component “plasma” or “Coulomb ga
s” is an\nimportant model of statistical physics\, which has a close con
nection\nwith eigenvalues of random matrices\, with zeroes of Gaussian ana
lytic\nfunctions\, and with determinantal point processes.\nI will give an
overview of some recent results showing a strong form of\n“order” amo
ng this system at all temperatures: hyperuniformity\,\nnumber-rigidity\, t
ranslation-invariance… some of which were predicted\nlong ago in the phy
sics literature.\nFiguring out its phase portrait remains nonetheless an o
pen question\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/177/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Morris Brooks (Zürich)
DTSTART:20251209T140000Z
DTEND:20251209T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/178
DESCRIPTION:Title: The effective mass of the Fröhlich polaron at strong coupling
\nby Morris Brooks (Zürich) as part of One world IAMP mathematical physic
s seminar\n\n\nAbstract\nQuantum reference frames allow for the imposition
of symmetry principles whilst treating all systems quantum mechanically.
I'll introduce one recent approach to the subject---the operational approa
ch\, and describe the motivation\, the framework\, some examples and main
results. I'll then indicate how the introduction of a quantum reference fr
ame for a quantum field theory on background with certain symmetries reduc
es the type of the von Neumann algebra describing the theory\, raising the
possibility of computing physically interesting quantities that are unava
ilable in standard (algebraic) quantum field theories. I'll conclude with
some open directions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/178/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefan Junk (Gakushuin)
DTSTART:20251111T140000Z
DTEND:20251111T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/180
DESCRIPTION:Title: The phase transition for the directed polymer model in higher dime
nsions\nby Stefan Junk (Gakushuin) as part of One world IAMP mathemati
cal physics seminar\n\n\nAbstract\nThe directed polymer model (or directed
polymer in a random environment) is a fundamental model for a random walk
(polymer) influenced by i.i.d. space-time disorder. The model was first i
ntroduced as an approximation for interfaces of the Ising model but has re
cently drawn intensive study due to its connection to the Kardar-Parisi-Zh
ang (KPZ) universality class. It exhibits a rich structure and interesting
phenomena still only partly understood. In spatial dimension d=1\, the pi
cture is by now relatively clear by making use of integrable models\, and
recent breakthroughs have expanded our understanding of the case d=2 as we
ll. \n\nThis talk will focus on recent progress in higher spatial dimensio
ns (d>2)\, where our understanding remains much more limited. Here\, the m
odel is known to undergo a phase transition from high temperature (weak di
sorder phase)\, where the polymer converges to Brownian motion under diffu
sive rescaling\, to low temperature (strong disorder phase)\, where the po
lymer localizes in small\, favorable corridors in the environment. Specifi
cally\, I will present our recent result that shows the equivalence of two
different notions of strong disorder and resolves the behavior at critica
lity. Based on joint work with Hubert Lacoin.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/180/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Spiegel (UC Davis)
DTSTART:20251014T140000Z
DTEND:20251014T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/181
DESCRIPTION:Title: A Classifying Space for Phases of Matrix Product States\nby Da
niel Spiegel (UC Davis) as part of One world IAMP mathematical physics sem
inar\n\n\nAbstract\nAlexei Kitaev has conjectured that there should be a l
oop spectrum consisting of spaces of gapped invertible quantum spin system
s\, indexed by spatial dimension d of the lattice. Motivated by Kitaev’s
conjecture\, I will detail a concrete construction of a topological space
B that plays the role of Kitaev’s space in d = 1\, specifically for tra
nslation invariant injective matrix product states (MPS). Having such a sp
ace is a useful tool in the discussion of parametrized phases of MPS\; in
fact it allows us to define a parametrized phase as a homotopy class of ma
ps into B. The space B is constructed as the quotient of a contractible sp
ace E of MPS tensors modulo gauge transformations. The projection map from
E to B is a quasifibration\, from which we can compute the homotopy group
s of the classifying space B by a long exact sequence. In particular\, B h
as the weak homotopy type K(Z\, 2) x K(Z\, 3)\, shedding light on Kitaev
’s conjecture in the context of MPS.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/181/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leon Loveridge (University of South-Eastern Norway)
DTSTART:20251125T140000Z
DTEND:20251125T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/182
DESCRIPTION:Title: An invitation to Operational Quantum Reference Frames\nby Leon
Loveridge (University of South-Eastern Norway) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nQuantum reference frames allow
for the imposition of symmetry principles whilst treating all systems qua
ntum mechanically. I'll introduce one recent approach to the subject---the
operational approach\, and describe the motivation\, the framework\, some
examples and main results. I'll then indicate how the introduction of a q
uantum reference frame for a quantum field theory on background with certa
in symmetries reduces the type of the von Neumann algebra describing the t
heory\, raising the possibility of computing physically interesting quanti
ties that are unavailable in standard (algebraic) quantum field theories.
I'll conclude with some open directions.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/182/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeffrey Schenker (Michigan State University)
DTSTART:20251028T140000Z
DTEND:20251028T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/183
DESCRIPTION:Title: Finitely Correlated States for Disordered Systems: theory\, an exa
mple\, and open problems\nby Jeffrey Schenker (Michigan State Universi
ty) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\n
Matrix Product States (MPS)\, and more generally Finitely Correlated State
s (FCS)\, have played an important role in the analysis of ground states o
f spin chains for almost four decades\, beginning with the introduction of
the AKLT model and the construction of its ground state by Afleck\, Kenne
dy\, Lieb\, and Tasaki in 1987. The general theory of translation invaria
nt FCS in the thermodynamic limit was developed in a paper by Fannes\, Nac
htergaele\, and Werner from 1992. In this talk\, I will present recent wo
rk developing a theory of disordered FCS whose statistical distribution is
translation invariant\, as one would expect for a system with homogeneous
spatial disorder. We will consider a disordered generalization of the AKL
T state with interesting properties: the state has exponential clustering\
, is inherently gapless\, in that it cannot be the ground state of any gap
ped local Hamiltonian\, and Tasaki's index for the state can be shown to e
qual -1\, indicating that it is\, in some sense\, "topologically protected
." Finally\, several open problems regarding disordered FCS will be presen
ted. (Joint work with Eric Roon)\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/183/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Bols (ETH Zürich)
DTSTART:20260106T140000Z
DTEND:20260106T150000Z
DTSTAMP:20260422T225925Z
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 IAMP mat
hematical physics seminar\n\n\nAbstract\nThe theory of superselection sect
ors\, first developed in algebraic quantum field theory and more recently
adapted to quantum spin systems by Naaijkens and Ogata\, provides a rigoro
us description of the anyonic excitations hosted by gapped ground states o
f (2+1)-dimensional quantum systems. After a brief introduction to the gen
eral framework\, I will sketch how the sector theory can be computed expli
citly in a class of exactly solvable models.\nThe talk is based on joint w
ork with Mahdie Hamdan\, Boris Kjær\, Pieter Naaijkens\, and Siddarth Vad
nerkar : arXiv:2310.19661\, arXiv:2503.15611\, arXiv:2511.21521\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/184/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Holger Gies (Friedrich Schiller University Jena)
DTSTART:20260120T140000Z
DTEND:20260120T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/185
DESCRIPTION:Title: Quantum field theories of relativistic Luttinger fermions\nby
Holger Gies (Friedrich Schiller University Jena) as part of One world IAMP
mathematical physics seminar\n\n\nAbstract\nWe propose relativistic Lutti
nger fermions as a new ingredient for\nthe construction of fundamental qua
ntum field theories. The resulting fermion\nfields exhibit a canonical sca
ling different from Dirac fermions and thus\nsupport the construction of n
ovel relativistic and perturbatively\nrenormalizable\, interacting quantum
field theories in four spacetime\ndimensions. In particular\, new asympto
tically free self-interacting field\ntheories can be identified\, represen
ting first examples of high-energy complete\nquantum field theories based
on purely fermionic matter degrees of freedom. As\nexamples\, we discuss m
odels which undergo dimensional transmutation and low-\nenergy condensate
formation with scalar excitations on top of the condensate.\nWe observe th
at a corresponding Yukawa model exhibits features similar to\nself-organiz
ed criticality with a natural separation of low-energy observables\nfrom h
igh energy initial scales without the need for any fine-tuning. We also\nc
ritically examine the analytic structure of the Luttinger-fermionic\npropa
gator in the various gapped phases and discuss possible consequences for\n
asymptotic states.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/185/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Corwin (Columbia)
DTSTART:20260203T140000Z
DTEND:20260203T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/186
DESCRIPTION:Title: Extreme Diffusion\nby Ivan Corwin (Columbia) as part of One wo
rld IAMP mathematical physics seminar\n\n\nAbstract\nTwo hundred years 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 deve
lop an effective theory describing this motion as that of a random walker.
In this talk\, I will challenge a key implication of this well establishe
d theory. When studying systems with very large numbers of particles diffu
sing together\, I will argue that the Einstein random walk theory breaks d
own when it comes to predicting the statistical behavior of extreme partic
les—those that move the fastest and furthest in the system. In its place
\, I will describe a new theory of extreme diffusion which captures the ef
fect of the hidden environment in which particles diffuse together and all
ows us to interrogate that environment by studying extreme particles. I wi
ll highlight one piece of mathematics that led us to develop this theory
—a non-commutative binomial theorem—and hint at other connections to i
ntegrable probability\, quantum integrable systems and stochastic PDE.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/186/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Pérez García (UCM\, Madrid)
DTSTART:20260303T140000Z
DTEND:20260303T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/187
DESCRIPTION:Title: Haag Duality for 2D Quantum Spin Systems\nby David Pérez Garc
ía (UCM\, Madrid) as part of One world IAMP mathematical physics seminar\
n\n\nAbstract\nHaag duality is a fundamental locality property introduced
in the pioneering formulation of algebraic quantum field theory by Haag an
d Kastler in the 1960s. Since then\, it has played a central role\, most n
otably in the classification of superselection sectors by Doplicher\, Haag
\, and Roberts in the 1970s. Over the past two decades\, this concept has
migrated from its relativistic origins to quantum spin systems\, becoming
a cornerstone of the operator-algebraic approach to the long-standing prob
lem of classifying two-dimensional topological quantum phases of matter. H
owever\, rigorous proofs of Haag duality in two dimensions were previously
restricted to systems exhibiting abelian anyons. In this talk\, we will e
stablish Haag duality for a broad class of tensor network models\, expecte
d to include representatives of all non-chiral topological quantum phases
of matter.\n
LOCATION:https://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:20260422T225925Z
UID:IAMP_seminars/188
DESCRIPTION:Title: Keller estimates of the eigenvalues in the gap of Dirac operators<
/a>\nby David Gontier (CERMICS\, Ecole Nationale des Ponts et Chaussées\,
France) as part of One world IAMP mathematical physics seminar\n\n\nAbstr
act\nThe Keller inequality is the Lp version of the well-known Lord Rayley
gh problem: "What shape of drum produces the lowest note?”\, but this ti
me\, the drum is a potential with fixed Lp norm. In the usual Schrödinger
case\, was solved by Faber and Krahn around 1920\, and turns out to be eq
uivalent to the Gagliardo-Niremberg inequality. However\, the usual techni
ques do not apply to the Dirac case. \nIn this talk\, I will provide a nov
el technique which allows to tackle the problem both for Schrödinger and
Dirac operators\, and which provides interesting numerical schemes for thi
s optimization problem. I will mention several open problems related to th
e Dirac case.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/188/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcos Marino (Geneva)
DTSTART:20260428T140000Z
DTEND:20260428T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/189
DESCRIPTION:Title: Trans-series in quantum field theory\nby Marcos Marino (Geneva
) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\nIn
quantum field theory (QFT)\, perturbative series give only asymptotic app
roximations to observables.\nIs it possible to upgrade these series to exa
ct results? We know that this can be done\nin some situations -like the on
e-dimensional WKB method- by promoting perturbative series to so-called tr
ans-series.\nTrans-series are generalizations of perturbative series that
include exponentially small non-perturbative\neffects. In this talk I will
provide an overview of trans-series in QFT\, where these non-perturbative
effects\nare typically due to instantons and renormalons/condensates. I w
ill illustrate\ntheir general properties with concrete examples in asympto
tically free theories in two dimensions\, and\nI will give evidence that\,
in integrable field theories\, some observables can be exactly captured\n
by the resummation of trans-series.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/189/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Hinrichs (Paderborn)
DTSTART:20260317T140000Z
DTEND:20260317T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/190
DESCRIPTION:Title: Wavefunction Renormalization of Linear Field-Matter Interactions\nby Benjamin Hinrichs (Paderborn) as part of One world IAMP mathematica
l physics seminar\n\n\nAbstract\nLinear interactions between a quantum fie
ld and non-relativistic matter appear in various mathematical and physical
frameworks\, ranging from quantum optics and open quantum systems over ef
fective models for impurity-environment interactions to toy models of quan
tum field theory. In most applications\, the models suffer from both infra
red and ultraviolet singularities\, thus necessitating the need for renorm
alization. Whereas in some cases a so-called self-energy renormalization s
uffices\, which can be carried out in the Hamiltonian formalism\, more sin
gular interactions require a wavefunction renormalization\, which resemble
s the fact that the interacting vacuum is disjoint from the bare one.\n\nI
n this talk\, we first recall several relevant models and therein discuss
the implications of infrared and ultraviolet singularities. We then introd
uce a Hamiltonian-based wavefunction renormalization scheme and discuss ho
w it overcomes both the infrared and the ultraviolet problem in these mode
ls. The talk is based on joint work with Marco Falconi and Javier Valentí
n Martín.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/190/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Rademacher (University of Mannheim)
DTSTART:20260512T140000Z
DTEND:20260512T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/191
DESCRIPTION:Title: Long-time validity of Bogoliubov theory\nby Simone Rademacher
(University of Mannheim) as part of One world IAMP mathematical physics se
minar\n\n\nAbstract\nWe consider the Bogoliubov approximation for the many
-body quantum dynamics of weakly interacting Bose gases and establish a un
iform-in-time validity of Bogoliubov theory. The proof relies on a detaile
d analysis of the dispersive behavior of the symplectic Bogoliubov dynamic
s\, which allows for a rigorous derivation of the Bogoliubov theory as an
effective description of quantum fluctuations around the Bose-Einstein con
densate on all time scales. This is joint work with Phan Thanh Nam and Avy
Soffer.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/191/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomotaka Kuwahara (RIKEN)
DTSTART:20260331T140000Z
DTEND:20260331T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/192
DESCRIPTION:Title: Entanglement Hamiltonian on subsystem at non-zero temperatures
\nby Tomotaka Kuwahara (RIKEN) as part of One world IAMP mathematical phys
ics seminar\n\n\nAbstract\nThe entanglement Hamiltonian is an effective Ha
miltonian that describes the properties of a subsystem after taking the pa
rtial trace over the rest of the system. It plays a crucial role in variou
s areas\, including clustering of conditional mutual information\, Hamilto
nian learning\, and quantum algorithms\, etc [1]. However\, determining th
e structure of the entanglement Hamiltonian is generally a challenging pro
blem. Even at sufficiently high temperatures\, the standard cluster expans
ion method is indicated to be ineffective [2].\n\nIn this talk\, I will pr
esent an alternative approach to studying the entanglement Hamiltonian tha
t works across all temperature regimes. I will also discuss the limitation
s of this method and its implications for further research.\n\n[1] Tomotak
a Kuwahara\, Clustering of Conditional Mutual Information and Quantum Mark
ov Structure at Arbitrary Temperatures\, Physical Review X 15\, 041010 (20
25)\n\n[2] Kohtaro Kato\, Tomotaka Kuwahara\, Clustering of Conditional Mu
tual Information via Quantum Belief-Propagation Channels\, arXiv:2504.0223
5v2\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/192/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Piet Lammers (CNRS\, Sorbonne Université\, LPSM)
DTSTART:20260414T140000Z
DTEND:20260414T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/193
DESCRIPTION:Title: Gaussian free field convergence of the six-vertex model with Delta
between -1 and -1/2\nby Piet Lammers (CNRS\, Sorbonne Université\, L
PSM) as part of One world IAMP mathematical physics seminar\n\n\nAbstract\
nIn recent joint work with H. Duminil-Copin\, K. Kozlowski\, and I. Manole
scu\, we proved convergence of the full-plane six-vertex model towards the
Gaussian free field\, with an explicit scaling constant. The proof involv
es both techniques from non-integrable systems (percolation theory\, refle
ction positivity) and integrable systems (Yang-Baxter\, Bethe Ansatz). 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://researchseminars.org/talk/IAMP_seminars/193/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marcin Napiórkowski (University of Warsaw)
DTSTART:20260526T140000Z
DTEND:20260526T150000Z
DTSTAMP:20260422T225925Z
UID:IAMP_seminars/194
DESCRIPTION:Title: The Spin-Wave Approximation in the Quantum Heisenberg Model\nb
y Marcin Napiórkowski (University of Warsaw) as part of One world IAMP ma
thematical physics seminar\n\n\nAbstract\nSpin wave theory suggests that l
ow temperature properties of the Heisenberg model can be described in term
s of noninteracting quasiparticles called magnons. In my talk I will revie
w the basic concepts and predictions of spin wave approximation and report
on recent rigorous results in that direction.\n
LOCATION:https://researchseminars.org/talk/IAMP_seminars/194/
END:VEVENT
END:VCALENDAR