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BEGIN:VEVENT
SUMMARY:Maxim Chernodub (Institut Denis Poisson\, Université de Tours\, F
rance)
DTSTART:20211116T130000Z
DTEND:20211116T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/1
DESCRIPTION:Title: Machine-learning applied to deconfinement phase transitions and topolo
gical defects\nby Maxim Chernodub (Institut Denis Poisson\, Universit
é de Tours\, France) as part of Seed Seminar of Mathematics and Physics\n
\n\nAbstract\nWe discuss the advantages of machine learning techniques in
recognizing the dynamics of topological objects and building order paramet
ers associated with phase transitions in lattice quantum field theories. W
e consider the compact $U(1)$ gauge theory in three spacetime dimensions a
s the simplest example of a theory that exhibits confinement and mass gap
phenomena generated by monopoles. We train a neural network with a Monte-C
arlo generated set of monopole configurations\, treated as three-dimension
al holograms\, to distinguish between confinement and deconfinement phases
in a supervised learning approach. We show that a well-trained neural net
work may distinguish between confining and nonconfining monopole configura
tions "from a single glimpse'' with reasonable accuracy. As a second examp
le\, we discuss the ability of a neural network to (re)build a gauge-invar
iant deconfinement order parameter in the finite-temperature lattice Yang-
Mills theory. Some comments on current-state applications of machine learn
ing techniques to lattice gauge theories will also be given.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Richard (LAMA\, CNRS and Université Paris-Est Créteil\, F
rance)
DTSTART:20211130T150000Z
DTEND:20211130T160000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/2
DESCRIPTION:Title: Quantitative implications of positive scalar curvature\nby Thomas
Richard (LAMA\, CNRS and Université Paris-Est Créteil\, France) as part
of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nComparison inequ
alities (Toponogov\, Myers\, Bishop-Gromov) are essential tools in studyin
g manifolds with positive sectional or Ricci curvature. Until recently\, t
hese tools had no analog in the context of manifolds with positive scalar
curvature: all\nthe results on these kinds of manifolds were topological i
n nature.\nWe will present more or less recent progress in this direction
due to Gromov using minimal hypersurfaces as well as what Gromov calls the
“mu-bubbles.” In particular\, we will show that a metric with scalar
curvature greater than $ n(n-1)$ on $\\mathbb{T}^{n-1} \\times [-1\,1]\\\;
(n \\leq 7) $\ncannot have its two boundary components too far apart. W
e will conclude by showing how the positive scalar curvature controls the
size of minimal 2-spheres in $ \\mathbb{S}_2 \\times \\mathbb{T}^{n-2}\,
\\mathbb{S}_2 \\times \\mathbb{R}^2 $ and $ \\mathbb{S}_2 \\times \\mathb
b{S}_2$.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yoshimasa Hidaka (Institute of Particle and Nuclear Studies\, KEK\
, Japan)
DTSTART:20211214T110000Z
DTEND:20211214T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/3
DESCRIPTION:Title: Generalization of the Nambu-Goldstone theorem\nby Yoshimasa Hidaka
(Institute of Particle and Nuclear Studies\, KEK\, Japan) as part of Seed
Seminar of Mathematics and Physics\n\n\nAbstract\nSymmetry and its sponta
neous breaking are basic concepts in modern physics. When a continuum symm
etry is spontaneously broken\, there appears a gapless mode called the Nam
bu-Goldstone (NG) mode\, which is developed in a Lorentz invariant system\
, and is known as the Nambu-Goldstone theorem. In this talk\, we discuss t
he generalization of the Nambu-Goldstone theorem to various systems: a non
-relativistic system\, a system with higher-form symmetries\, and open cla
ssical and quantum systems. We will show that there also appears an NG mod
e in these systems when symmetry is spontaneously broken.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clotilde Fermanian-Kammerer (LAMA\, CNRS and Université Paris-Est
Créteil\, France)
DTSTART:20220118T130000Z
DTEND:20220118T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/4
DESCRIPTION:Title: Semi-classical analysis and the correspondence principle\nby Cloti
lde Fermanian-Kammerer (LAMA\, CNRS and Université Paris-Est Créteil\, F
rance) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nI
n this talk\, we will explain the basis of the semi-classical approach\, s
ome of the ideas and results obtained in this context and we will describe
its position at the interface between mathematics and physics or theoreti
cal chemistry.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kazuya Mameda (RIKEN\, Japan)
DTSTART:20220201T100000Z
DTEND:20220201T110000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/5
DESCRIPTION:Title: Quantum kinetic theory in curved spacetime\nby Kazuya Mameda (RIKE
N\, Japan) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstrac
t\nIn this talk\, I will explain my recent works about the kinetic theory
under external gravity. I will first show its field-theoretical derivation
keeping the general covariance. From this framework\, we obtain new types
of fermionic transport phenomena induced by gravity\; in particular\, the
coupling between spin and Riemann curvature yields the antiparallel flows
of charge and energy. These phenomena are applicable not only to fermioni
c systems under genuine gravity\, but also to the ones with background flu
id motion or temperature gradient. I will briefly discuss possible applica
tions to high-energy and condensed matter physics. I will also talk about
photonic kinetic theory in curved spacetime and its implication.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giacomo De Palma (University of Bologna\, Italy)
DTSTART:20220215T130000Z
DTEND:20220215T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/6
DESCRIPTION:Title: The quantum Wasserstein distance of order 1\nby Giacomo De Palma (
University of Bologna\, Italy) as part of Seed Seminar of Mathematics and
Physics\n\n\nAbstract\nWe propose a generalization of the Wasserstein dist
ance of order 1 to the quantum states of n\n qudits. The proposal recovers
the Hamming distance for the vectors of the canonical basis\, and more ge
nerally the classical Wasserstein distance for quantum states diagonal in
the canonical basis. The proposed distance is invariant with respect to pe
rmutations of the qudits and unitary operations acting on one qudit and is
additive with respect to the tensor product. We prove a continuity bound
for the von Neumann entropy with respect to the proposed distance\, which
significantly strengthens the best continuity bound with respect to the tr
ace distance. We also propose a generalization of the Lipschitz constant t
o quantum observables. The notion of quantum Lipschitz constant allows us
to compute the proposed distance with a semidefinite program. We prove a q
uantum version of Marton’s Transportation-Cost Inequality (TCI) for prod
uct states and a quantum Gaussian concentration inequality for the spectru
m of quantum Lipschitz observables. Furthermore\, we prove two generalizat
ions of Marton’s TCI to Gibbs states of quantum commuting Hamiltonians.
The first relies on a quantum generalization of Dobrushin’s uniqueness c
ondition\, while the second relies on a quantum generalization of Ollivier
’s coarse Ricci curvature. Finally\, we apply our results to prove the e
quivalence of the canonical and microcanonical ensembles of quantum statis
tical mechanics.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mahmut Elbistan (Bogazici University\, Turkey)
DTSTART:20220301T130000Z
DTEND:20220301T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/7
DESCRIPTION:Title: Circularly polarized periodic gravitational wave and the Pais-Uhlenbec
k oscillator\nby Mahmut Elbistan (Bogazici University\, Turkey) as par
t of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nThe “Bargman
n framework” allows us to prove the equivalence of the Pais-Uhlenbeck os
cillator with a spin-zero particle in a circularly polarized periodic grav
itational wave. Pushing forward the symmetries (which include Carroll symm
etry) of the latter\, we derive conserved charges for the Pais-Uhlenbeck o
scillator.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Raujouan (Institut für Differentialgeometrie\, University
of Hanover\, Germany)
DTSTART:20220315T130000Z
DTEND:20220315T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/8
DESCRIPTION:Title: Soap bubbles: a gauge theory\nby Thomas Raujouan (Institut für Di
fferentialgeometrie\, University of Hanover\, Germany) as part of Seed Sem
inar of Mathematics and Physics\n\n\nAbstract\nConstant Mean Curvature (CM
C) surfaces are mathematical models for soap films\, with or without volum
e constraints. The equations governing them form an integrable system whic
h can be formulated in a gauge theoretic point of view. This formulation l
eads to a generalized holomorphic representation for CMC surfaces in Eucli
dean\, Spherical and Hyperbolic three-spaces\, which allows for the constr
uction of new surfaces\, together with the computation of their areas and
proofs of their embeddedness.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pietro Benetti Genolini (King's College London\, United Kingdom)
DTSTART:20220329T120000Z
DTEND:20220329T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/9
DESCRIPTION:Title: Localization of the action in AdS/CFT\nby Pietro Benetti Genolini
(King's College London\, United Kingdom) as part of Seed Seminar of Mathem
atics and Physics\n\n\nAbstract\nI will introduce a simple formula for the
action of supersymmetric solutions to minimal gauged supergravity in the
context of the AdS/CFT correspondence. Such solutions are equipped with a
Killing vector\, and I will show that the holographically renormalized act
ion may be expressed entirely in terms of the weights of this vector field
at its fixed points\, together with certain topological data. In this sen
se\, the classical gravitational partition function localizes in the bulk\
, and depends only on the topology of the fixed point set.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edoardo Lauria (École Polytechnique\, France)
DTSTART:20220419T120000Z
DTEND:20220419T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/10
DESCRIPTION:Title: Conformal boundary conditions for free fields\nby Edoardo Lauria
(École Polytechnique\, France) as part of Seed Seminar of Mathematics and
Physics\n\n\nAbstract\nI will discuss the problem of classifying (interac
ting) conformal boundary conditions for the simplest bulk conformal field
theories: free fields. I will mention concrete examples based on perturbat
ion theory\, and then describe results using the numerical conformal boots
trap approach\, specifically in the case of a scalar field in four and thr
ee bulk dimensions.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Utku Zorba (Bogazici University\, Turkey)
DTSTART:20220510T120000Z
DTEND:20220510T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/11
DESCRIPTION:Title: Carrollian and Non-relativistic Jackiw-Teitelboim Supergravity\nb
y Utku Zorba (Bogazici University\, Turkey) as part of Seed Seminar of Mat
hematics and Physics\n\n\nAbstract\nWe present non- and ultra-relativistic
Jackiw-Teitelboim (JT) supergravity as metric BF theories based on the ex
tended Newton-Hooke and extended $\\text{AdS}$ Carroll super-algebras in t
wo spacetime dimensions\, respectively. The extended Newton-Hooke structur
e\, and\, in particular\, the invariant metric necessary for the BF constr
uction of non-relativistic JT supergravity\, is obtained by performing an
expansion of the $N=2$ $\\text{AdS}$ super algebra. Subsequently\, we intr
oduce the extended $\\text{AdS}_2$ Carroll super algebra\, and the associa
ted invariant metric\, as a suitable redefinition of the extended Newton-H
ooke super algebra. The mapping involved can be seen as the supersymmetric
extension of the duality existing at the purely bosonic level between the
extended Newton-Hooke algebra with (positive) negative cosmological const
ant and the extended $\\text{(A)dS}$ Carroll algebra in two dimensions. Fi
nally\, we provide the Carrollian JT supergravity action in the BF formali
sm. Moreover\, we show that both the non-relativistic and the ultra-relati
vistic theories presented can also be obtained by direct expansion of $N=2
$ JT supergravity.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Manuel (Instituto de Ciencias del Espacio\, Consejo Super
ior de Investigaciones Científicas\, Barcelona\, Spain)
DTSTART:20220517T120000Z
DTEND:20220517T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/12
DESCRIPTION:Title: Chiral Kinetic Theory with small mass corrections and quantum coheren
t states\nby Cristina Manuel (Instituto de Ciencias del Espacio\, Cons
ejo Superior de Investigaciones Científicas\, Barcelona\, Spain) as part
of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIn systems made
up of massless fermions\, the hydrodynamical equations have to include the
effects of the chiral quantum anomaly. The so-called anomalous hydrodynam
ics might be derived from a microscopic approach\, chiral kinetic theory\,
which contains quantum corrections to classical transport equations. We e
xplain how quantum effects might be incorporated in transport theory\, usi
ng effective field theory techniques. We also study the effect of a small
fermion mass in the formulation of the chiral kinetic theory. Besides the
left-handed and right-handed distribution functions components needed in t
he massless case\, distribution functions describing quantum coherent mixt
ures of left and right-handed fermions are also required\, which also ente
r in the chiral anomaly equation. We study how these two different sets of
functions are related by Lorentz symmetry transformations.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maurice de Gosson (Faculty of Mathematics (NuHAG)\, University of
Vienna\, Austria)
DTSTART:20220531T120000Z
DTEND:20220531T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/13
DESCRIPTION:Title: On the notions of mixed Gaussian quantum states and density operators
\nby Maurice de Gosson (Faculty of Mathematics (NuHAG)\, University of
Vienna\, Austria) as part of Seed Seminar of Mathematics and Physics\n\n\
nAbstract\nOne cornerstone of quantum mechanics is the notion of mixed qua
ntum state. In this talk\, we will give a mathematically rigorous definiti
on of this concept and of the associated notion of density operator from t
he point of view of harmonic analysis and symplectic geometry. We will dis
cuss in detail the case of so-called gaussian states which play a major ro
le in the applications to quantum information and optics.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karl Landsteiner (Instituto de Física Teórica\, Consejo Superior
de Investigaciones Científicas\, Madrid\, Spain)
DTSTART:20220607T120000Z
DTEND:20220607T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/14
DESCRIPTION:Title: Quantum Anomalies and Matter\nby Karl Landsteiner (Instituto de F
ísica Teórica\, Consejo Superior de Investigaciones Científicas\, Madri
d\, Spain) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstrac
t\nMassless fermions possess chiral symmetries on the classical level. The
se symmetries are however broken by quantum effects. In particle physics t
hey lead to the decay of the neutral pion and to important consistency con
straints on chiral gauge theories such as the standard model. Anomalies al
so have important consequences at finite temperature and finite density. t
hey lead then to new transport effects\, the chiral magnetic and chiral vo
rtical effects. I will review the theory of anomaly induced transport\, it
s application to condensed matter and high energy physics\, and give an ou
tlook on recent developments.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quentin Berger (Laboratoire de Probabilités Statistique et Modél
isation\, Sorbonne Université\, Paris\, France)
DTSTART:20220621T120000Z
DTEND:20220621T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/15
DESCRIPTION:Title: Directed polymers and the Stochastic Heat Equation with heavy-tail no
ise\nby Quentin Berger (Laboratoire de Probabilités Statistique et Mo
délisation\, Sorbonne Université\, Paris\, France) as part of Seed Semin
ar of Mathematics and Physics\n\n\nAbstract\nI will introduce the directed
polymer model in dimension $1+d$\n\, which describes a one-dimensional po
lymer chain placed in some disordered medium. I will give an overview of t
he model and I will discuss its relation to the stochastic heat equation (
SHE) with multiplicative noise. This has been widely studied in the case w
here the disorder admits a second moment \; it corresponds to the SHE with
Gaussian white noise. I will then present the results obtained in collabo
ration with Carsten Chong (Columbia\, USA) and Hubert Lacoin (IMPA\, Brazi
l) on the directed polymer model and the SHE with Lévy noise.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eveliina Peltola (Hausdorff Center for Mathematics\, University of
Bonn\, Germany\, and Aalto University\, Finland)
DTSTART:20221108T130000Z
DTEND:20221108T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/16
DESCRIPTION:Title: Towards a conformal field theory for Schramm-Loewner evolutions?\
nby Eveliina Peltola (Hausdorff Center for Mathematics\, University of Bon
n\, Germany\, and Aalto University\, Finland) as part of Seed Seminar of M
athematics and Physics\n\n\nAbstract\nFor a number of critical lattice mod
els in $2D$\n statistical physics\, it has been proven that scaling limits
of interfaces (with suitable boundary conditions) are described by Schram
m-Loewner evolution (SLE) curves. So-called partition functions of these S
LEs (which also encode macroscopic crossing probabilities) can be regarded
as specific correlation functions in the conformal field theory (CFT) ass
ociated to the lattice model in question. Although it is not clear how to
define the latter mathematically\, one can still make sense of many of the
properties predicted for these CFTs. In particular\, all of the expected
CFT properties: conformal invariance\, null-field equations\, and fusion r
ules\, are satisfied by the partition functions. One might then ask: Is it
possible to go deeper and to construct the appropriate CFT fields as rand
om distributions? Time permitting\, I discuss some ideas to this direction
.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kostas Skenderis (University of Southampton\, United Kingdom)
DTSTART:20221122T150000Z
DTEND:20221122T160000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/17
DESCRIPTION:Title: Conformal Field Theory in momentum space\nby Kostas Skenderis (Un
iversity of Southampton\, United Kingdom) as part of Seed Seminar of Mathe
matics and Physics\n\n\nAbstract\nI will give an overview of conformal fie
ld theory in momentum space. In particular\, I will present the solution o
f conformal Ward identities for $n$-point correlation functions and then d
iscuss renormalisation and conformal anomalies.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emilio Trevisani (École Polytechnique\, France)
DTSTART:20221213T130000Z
DTEND:20221213T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/18
DESCRIPTION:Title: Random field models and Parisi-Sourlas supersymmetry\nby Emilio T
revisani (École Polytechnique\, France) as part of Seed Seminar of Mathem
atics and Physics\n\n\nAbstract\nThe problem of quenched disorder is very
important but notoriously hard. In 1979\, Parisi and Sourlas proposed a co
njecture about the critical behaviour of models with random field type of
disorder. The conjecture states that 1) such models have emergent supersym
metry and 2) that supersymmetry allows to describe them in terms of models
in two less dimensions. I will review the conjecture and explain some rec
ent developments on the subject.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudio Corianò (Department of Mathematics and Physics "Ennio De
Giorgi"\, University of Salento\, and INFN\, Lecce\, Italy)
DTSTART:20221220T130000Z
DTEND:20221220T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/19
DESCRIPTION:Title: Testing Anomaly Induced Actions using CFT in momentum space\nby C
laudio Corianò (Department of Mathematics and Physics "Ennio De Giorgi"\,
University of Salento\, and INFN\, Lecce\, Italy) as part of Seed Seminar
of Mathematics and Physics\n\n\nAbstract\nConformal field theory in momen
tum space provides the general framework for investigating effects of conf
ormal and chiral anomalies in parity even and parity odd conformal correla
tors. The connection of the momentum space formalism with gravity is defin
ed by the conformal anomaly effective action. This action summarizes the c
onformal Ward identities of the flat space correlators in a general framew
ork\, and it accounts for the conformal anomaly. We are going to illustrat
e the relation between conformal anomaly actions\, the Conformal Ward iden
tities constraining the CFT correlators\, and the so-called “anomaly ind
uced actions”. An analysis of 4-point functions derived from such action
s appears to be inconsistent with the perturbative result. These investiga
tions find application in very different areas of physics\, from topologic
al insulators to non-local gravity and Einstein-Gauss-Bonnet theories.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bram Petri (Institut de Mathématiques de Jussieu-Paris Rive Gauch
e\, Sorbonne Université\, Paris\, France)
DTSTART:20230207T130000Z
DTEND:20230207T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/20
DESCRIPTION:Title: Linear programming on hyperbolic surfaces\nby Bram Petri (Institu
t de Mathématiques de Jussieu-Paris Rive Gauche\, Sorbonne Université\,
Paris\, France) as part of Seed Seminar of Mathematics and Physics\n\n\nAb
stract\nI will speak about extremal problems in the (spectral) geometry of
hyperbolic surfaces and how linear programming methods based on the Selbe
rg trace formula can help. I will not assume any familiarity with hyperbol
ic geometry or the Selberg trace formula. This is joint work with Maxime F
ortier Bourque.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yannick Herfray (Institut Denis Poisson\, Université de Tours\, F
rance)
DTSTART:20230228T130000Z
DTEND:20230228T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/21
DESCRIPTION:Title: Geometrical asymptotics in General Relativity\nby Yannick Herfray
(Institut Denis Poisson\, Université de Tours\, France) as part of Seed
Seminar of Mathematics and Physics\n\n\nAbstract\nIn general relativity th
ere are several classical notions of asymptotic flatness: In effect these
amount to the possibility of “adding a boundary at infinity” to the cu
rved spacetime. The exact procedure and geometry is however very different
depending on whether one considers an asymptote in null\, time-like\, or
space-like directions. I will show that these can nonetheless all be deriv
ed from one unique concept\, curved obit decomposition of Cartan geometry\
, and that there is therefore a profound unity in these notions of asympto
tics.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alicia Castro (Radboud University\, Nijmegen\, the Netherlands)
DTSTART:20230328T110000Z
DTEND:20230328T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/22
DESCRIPTION:Title: Scale-invariant random geometries from mating of trees\nby Alicia
Castro (Radboud University\, Nijmegen\, the Netherlands) as part of Seed
Seminar of Mathematics and Physics\n\n\nAbstract\nIn this talk\, I present
new results on the search for scale-invariant random geometries in the co
ntext of Quantum Gravity. To uncover new universality classes of such geom
etries\, we generalized the mating of trees approach\, which encodes Liouv
ille Quantum Gravity on the 2-sphere in terms of a correlated Brownian mot
ion describing a pair of random trees. We extended this approacyouh to hig
her-dimensional correlated Brownian motions\, leading to a family of non-p
lanar random graphs that belong to new universality classes of scale-invar
iant random geometries. We developed a numerical method to efficiently sim
ulate these random graphs and explore their scaling limits through distanc
e measurements\, allowing us to estimate Hausdorff dimensions in the two-
and three-dimensional settings.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anna Paola Muntoni (DISAT\, Polytechnic University of Turin\, Ital
y)
DTSTART:20230502T120000Z
DTEND:20230502T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/23
DESCRIPTION:Title: An approximate solution for the compressed sensing problem using stat
istical mechanics tool\nby Anna Paola Muntoni (DISAT\, Polytechnic Uni
versity of Turin\, Italy) as part of Seed Seminar of Mathematics and Physi
cs\n\n\nAbstract\nMany interesting problems in fields ranging from telecom
munications to computational biology can be formalized in terms of large u
nderdetermined systems of linear equations with additional constraints or
regularizers. One of the most studied\, the compressed sensing (CS) proble
m\, consists in finding the solution with the smallest number of non-zero
components of a given system of linear equations.\n\nIn this talk\, I will
address the CS problem within a Bayesian inference framework where the sp
arsity constraint is remapped into a singular prior distribution (called S
pike-and-Slab or Bernoulli–Gauss). A solution to the problem is attempte
d through the computation of marginal distributions via Expectation Propag
ation\, an iterative computational scheme originally developed in statisti
cal physics.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joonas Turunen (Faculty of Mathematics\, University of Vienna\, Au
stria)
DTSTART:20230516T120000Z
DTEND:20230516T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/24
DESCRIPTION:Title: Statistical mechanics models on random maps of the disk and the half-
plane\nby Joonas Turunen (Faculty of Mathematics\, University of Vienn
a\, Austria) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstr
act\nIn the main part of this talk\, which is mostly based on joint works
with Linxiao Chen\, we start from a purely combinatorial problem of random
planar triangulations of the disk coupled with the Ising model with Dobru
shin boundary conditions and at a fixed temperature (and without external
magnetic field). We identify rigorously a phase transition by analysing th
e critical behaviour of the partition functions of a large disk at and aro
und the critical temperature. Moreover\, we study the random geometric imp
lications of this in particular in a local limit when the disk perimeter t
ends to infinity. At the critical temperature\, we also find some explicit
scaling limits of observables related to the interface lengths\, which ha
ve interpretations in the continuum Liouville Quantum Gravity. The two key
techniques in use are singularity analysis of rational parametrizations o
f generating functions\, as well as the aforementioned exploration process
. At the end of the talk\, we will briefly discuss how this approach could
be applied in further investigations of the Ising model and generalized t
o other statistical mechanics models on similar random lattices.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ali Khezeli (Centre Inria de Paris\, France et Tarbiat Modares Uni
versity\, Teheran\, Iran)
DTSTART:20230530T120000Z
DTEND:20230530T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/25
DESCRIPTION:Title: Unimodular Random Measured Metric Spaces and Palm Theory on Them\
nby Ali Khezeli (Centre Inria de Paris\, France et Tarbiat Modares Univers
ity\, Teheran\, Iran) as part of Seed Seminar of Mathematics and Physics\n
\n\nAbstract\nIn this work\, we define the notion of unimodular random mea
sured metric spaces as a common generalization of various other notions. T
his includes the discrete cases like unimodular graphs and stationary poin
t processes\, as well as the non-discrete cases like stationary random mea
sures and the continuum metric spaces arising as scaling limits of graphs.
We provide various examples and prove many general results\; e.g.\, on we
ak limits\, re-rooting invariance\, random walks\, ergodic decomposition\,
amenability and balancing transport kernels. In addition\, we generalize
the Palm theory to point processes and random measures on a given unimodul
ar space. This is useful for Palm calculations and also for reducing some
problems to the discrete cases.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriele Sicuro (King's College London\, United Kingdom)
DTSTART:20230606T120000Z
DTEND:20230606T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/26
DESCRIPTION:Title: Classification of fat-tailed clusters in high dimensions\nby Gabr
iele Sicuro (King's College London\, United Kingdom) as part of Seed Semin
ar of Mathematics and Physics\n\n\nAbstract\nI will discuss the problem of
learning a mixture of two clouds of data points with generic centroids vi
a empirical risk minimisation in the high dimensional regime\, under the a
ssumptions of generic convex loss and convex regularisation. Each cloud of
data points is obtained by sampling from a possibly uncountable superposi
tion of Gaussian distributions\, whose variance has a generic probability
density ϱ. Our analysis covers therefore a large family of data distribut
ions\, including the case of power-law-tailed distributions with no covari
ance. We study the generalisation performance of the obtained estimator\,
we analyse the role of regularisation and the dependence of the separabili
ty transition on the distribution scale parameters.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Hutchcroft (Department of Mathematics\, California Institute o
f Technology\, Pasadena\, USA)
DTSTART:20230627T120000Z
DTEND:20230627T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/27
DESCRIPTION:Title: Critical behaviour in long-range and hierarchical percolation\nby
Tom Hutchcroft (Department of Mathematics\, California Institute of Techn
ology\, Pasadena\, USA) as part of Seed Seminar of Mathematics and Physics
\n\n\nAbstract\nStatistical mechanics models undergoing a phase transition
often exhibit rich\, fractal-like behaviour at their critical points\, wh
ich are described in part by critical exponents – the indices governing
the power-law growth or decay of various quantities of interest. These exp
onents are expected to depend on the dimension but not on the microscopic
details of the model such as the choice of lattice. After much progress ov
er the last thirty years we now understand two-dimensional and high-dimens
ional models rather well\, but intermediate dimensions such as three remai
n mysterious. I will discuss these issues in the context of long-range and
hierarchical percolation\, and in particular how we can now compute some
critical exponents for the hierarchical model in all dimensions.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aleix Gimenez-Grau (Institut des Hautes Études Scientifiques\, Bu
res-sur-Yvette\, France)
DTSTART:20231031T130000Z
DTEND:20231031T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/28
DESCRIPTION:Title: Scale without Conformal Invariance in Dipolar Ferromagnets\nby Al
eix Gimenez-Grau (Institut des Hautes Études Scientifiques\, Bures-sur-Yv
ette\, France) as part of Seed Seminar of Mathematics and Physics\n\n\nAbs
tract\nIt is a common belief that isotropic ferromagnets\, when tuned to t
heir critical temperature\, can be described by an RG fixed point in the u
niversality class of the Heisenberg model. Although this is often a good a
pproximation\, ferromagnets always contain dipolar interactions\, which le
ad to a different fixed point called the dipolar fixed point. In this talk
\, we point out that the dipolar fixed point is a field theory which is sc
ale but not conformal invariant. We show that this dipolar field theory en
joys a shift symmetry\, which is responsible for the lack of conformal inv
ariance and explains the non-renormalization of the virial current. In fac
t\, we observe that shift symmetry is the mechanism behind all other curre
ntly known models which are scale but not conformal invariant.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Pechersky (University of Toronto\, Canada)
DTSTART:20231114T150000Z
DTEND:20231114T160000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/29
DESCRIPTION:Title: Orthodiagonal maps\, tilings of rectangles and their convergence to t
he Riemann map\nby David Pechersky (University of Toronto\, Canada) as
part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nDiscrete c
omplex analysis is the study of discrete holomorphic functions. These are
functions defined on graphs embedded in the plane that satisfy some discre
te analogue of the Cauchy-Riemann equations. While the subject is classica
l\, it has seen a resurgence in the past 20-30 years with the work of Keny
on\, Mercat\, Smirnov\, and many others demonstrating the power of discret
e complex analysis as a tool for understanding 2D statistical physics at c
riticality.\n\nIn this talk\, we’ll discuss how discrete complex analysi
s can be applied to solve a purely deterministic problem for a very genera
l class of discretizations of 2D space accommodating a notion of discrete
complex analysis.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giuseppe Di Giulio (University of Würzburg\, Germany)
DTSTART:20231128T130000Z
DTEND:20231128T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/30
DESCRIPTION:Title: Charged moments and symmetry-resolved entanglement in two-dimensional
free conformal field theories\nby Giuseppe Di Giulio (University of W
ürzburg\, Germany) as part of Seed Seminar of Mathematics and Physics\n\n
\nAbstract\nRecently\, there has been an intense research activity on the
interplay between symmetries and entanglement in many-body quantum systems
\, exploiting the block-diagonal structure of the reduced density matrix (
RDM) in each charge sector. This talk aims to present results on the symme
try resolution of the entanglement in two-dimensional conformal field theo
ries. In this context\, helpful quantities are the charged moments and the
ir generalization to multi-charged moments\, which are propedeutic to the
computation of symmetry-resolved entanglement entropies and mutual informa
tion. These quantities can be seen as partition functions on multi-sheeted
Riemann surfaces and can be computed through suitable correlation functio
ns. I will present their computation for a massless Dirac field theory and
a massless compact boson. In the former case\, the calculation is reduced
to correlation functions of vertex operators on the complex plane. I will
discuss why this method cannot be applied in the latter example\, thus ma
king necessary computing correlation functions on surfaces with arbitrary
genus.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Baptiste Cerclé (École Polytechnique Fédérale de Lausanne\, La
usanne\, Switzerland)
DTSTART:20231212T130000Z
DTEND:20231212T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/31
DESCRIPTION:Title: A probabilistic approach to Toda Conformal Field Theories\nby Bap
tiste Cerclé (École Polytechnique Fédérale de Lausanne\, Lausanne\, Sw
itzerland) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstrac
t\nToda conformal field theories form a family of two-dimensional quantum
field theories initially introduced in the physics literature. They are na
tural generalizations of Liouville theory that enjoy\, in addition to conf
ormal invariance\, an enhanced level of symmetry encoded by W-algebras.\n\
nIn this presentation we will explain how one can study these theories fro
m a mathematically rigorous perspective. For this purpose we will describe
a probabilistic framework designed to make sense of these models and prov
ide some insight on how the introduction of this framework can help to und
erstand the model.\n\nTo be more specific\, we will prove ---we will not e
nter into much details but rather try to convey the main ideas--- that one
can compute some basic correlation functions of the theory based on proba
bilistic tools. Along the proof of this statement we will shed light on so
me unexpected interplays between probability theory and conformal field th
eory such as a generalized Brownian path decomposition.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Toninelli (CEREMADE - Université Paris Dauphine)
DTSTART:20240117T123000Z
DTEND:20240117T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/33
DESCRIPTION:Title: Bootstrap percolation and kinetically constrained models: universalit
y results\nby Cristina Toninelli (CEREMADE - Université Paris Dauphin
e) as part of Seed Seminar of Mathematics and Physics\n\nLecture held in M
aryam Mirzakhani (a.k.a. Salle 201 on 2nd floor)\, Institut Henri Poincar
é.\n\nAbstract\nRecent years have seen a great deal of progress in unders
tanding the behavior of bootstrap percolation (BP) models\, a particular c
lass of monotone cellular automata. In the initial configuration sites are
occupied with probability p. The evolution of BP occurs at discrete times
: empty sites stay empty and occupied sites are emptied iff a certain mode
l dependent neighborhood is already empty. In the Euclidean lattice there
is now a complete understanding of the large time evolution with a univers
ality picture for the critical behavior. Much less is known for their non-
monotone stochastic counterpart\, namely kinetically constrained models (K
CM). In KCM each vertex is updated independently at rate p (respectively 1
-p) to occupied (respectively empty) iff it could be emptied in the next
step by the bootstrap model. In the last two decades KCM have been the sub
ject of intensive research both in physics and mathematics literature. The
main motivation is that\, for certain choices of the constraints\, when p
goes to zero KCM display some of the most striking features of the liquid
/glass transition. Indeed\, they were originally introduced in the 80's to
support the free volume theories and later on used as the simplest lattic
e models reproducing the dynamical facilitation scenario. In this seminar
I will discuss some recent rigorous results on the characteristic time sca
les of KCM as p goes to zero as well as the connection with the critical
behavior of the corresponding BP models.\n\nPart of the kick-off event of
the seminar's winter 2024 thematic trimester "From discrete models to cond
ensed matter"\, at IHP (Paris). To attend in-person\, free but mandatory r
egistration here.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierre Le Bris (IHES - Université Paris-Saclay)
DTSTART:20240117T140000Z
DTEND:20240117T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/34
DESCRIPTION:Title: Proving Propagation of Chaos and Mean-field Limits\nby Pierre Le
Bris (IHES - Université Paris-Saclay) as part of Seed Seminar of Mathemat
ics and Physics\n\nLecture held in Maryam Mirzakhani (a.k.a. Salle 201 on
2nd floor)\, Institut Henri Poincaré.\n\nAbstract\nConsider a system of $
N$ particles\, described via a system of Stochastic Differential Equations
(SDEs)\, interacting in a mean field way. We are interested in the limit\
, as $N$ goes to infinity\, of this particle system\, and try to derive fr
om a microscopic point of view (i.e. particle dynamics) a mesoscopic point
of view (i.e. a statistical description of the system). The notion of pro
pagation of chaos refers to the phenomenon according to which\, as the num
ber of particles $N$ grows\, two given particles become « more and more
» statistically independent.\n\nThe aim of this talk is to discuss more o
r less recent methods to prove this phenomenon for different types of part
icle systems\, notably in singular Riesz-type interaction\, with ideas ran
ging from Probability theory to analysis of Partial Differential Equations
(PDEs). We focus in particular on quantitative and uniform in time propag
ation of chaos.\n\nThis talk is based on joint works with A. Guillin (univ
ersité Clermont-Auvergne) et P. Monmarché (Sorbonne Université).\n\nPar
t of the kick-off event of the seminar's winter 2024 thematic trimester "F
rom discrete models to condensed matter"\, at IHP (Paris). To attend in-pe
rson\, free but mandatory registration here.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anna Ritz-Zwilling (LPTMC - Sorbonne Université)
DTSTART:20240117T153000Z
DTEND:20240117T163000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/35
DESCRIPTION:Title: Partition function for string-net models\nby Anna Ritz-Zwilling (
LPTMC - Sorbonne Université) as part of Seed Seminar of Mathematics and P
hysics\n\nLecture held in Maryam Mirzakhani (a.k.a. Salle 201 on 2nd floor
)\, Institut Henri Poincaré.\n\nAbstract\nThe string-net models were intr
oduced by Levin and Wen (1) as exactly solvable models of topological orde
r in two dimensions. The latter appears in strongly interacting or frustr
ated systems and is characterized by the presence of point-like excitation
s\, called anyons\, with exotic (i.e. neither fermionic nor bosonic) excha
nge statistics. Built from a unitary fusion category\, the string-net mode
ls realize a topological order corresponding to the Drinfeld center of the
category. The energy spectrum of these models is trivial but the degenera
cies are not. In particular\, they depend on the genus of the surface on w
hich the model is defined. After introducing the models\, I will show how
to compute these degeneracies and obtain the exact partition function of t
hese models\, opening the way to their study at finite temperature (2\, 3)
.\n\n(1) M. A. Levin and X.-G. Wen\, Phys. Rev. B 71\, 045110 (2005)\n\n
(2) J. Vidal\, Phys. Rev. B 105\, L041110 (2020)\n\n(3) A. Ritz-Zwilling
\, J.-N. Fuchs\, J. Vidal\, S. H. Simon\, https://arxiv.org/abs/2309.00343
\n\nPart of the kick-off event of the seminar's winter 2024 thematic trime
ster "From discrete models to condensed matter"\, at IHP (Paris). To atten
d in-person\, free but mandatory registration here.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Haina Wang (Princeton University\, Princeton\, New Jersey\, USA)
DTSTART:20240130T140000Z
DTEND:20240130T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/36
DESCRIPTION:Title: Inverse Statistical Mechanics: Inferring Interactions from Materials
’ Spectra\nby Haina Wang (Princeton University\, Princeton\, New Jer
sey\, USA) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstrac
t\nThe inverse problem in statistical mechanics aims to find microscopic s
tructures or interactions that correspond to macroscopic properties. In my
talk\, I will review some challenges for common methods to extract effect
ive interactions from the pair correlation function $g_2(r)$ [or equivalen
tly\, the structure factor $S(k)$] of many-body systems\, such as their ef
fective ambiguity of solutions despite a uniqueness theorem. Next\, I will
introduce my work to overcome such challenges by developing an inverse me
thodology that is accurate\, efficient\, and robust to noise. This methodo
logy has enabled us to quantify the "nonequilibriumness" of many-body syst
ems\, study the structural degeneracy ("isospectral") problem\, and probe
the realizability of prescribed pair correlation functions. We expect our
approach to facilitate the design of self-assembly of materials with desir
ed optical and transport properties. Finally\, I will comment on how inver
se statistical mechanics can be extended to active-matter systems and how
the recent development of stochastic automatic differentiation may be appl
ied to devise more efficient inverse algorithms.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Cuomo (Department of Physics\, Princeton University\, Prin
ceton\, New Jersey\, USA)
DTSTART:20240213T130000Z
DTEND:20240213T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/37
DESCRIPTION:Title: Spontaneous symmetry breaking on surface defects\nby Gabriel Cuom
o (Department of Physics\, Princeton University\, Princeton\, New Jersey\,
USA) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nCo
leman’s theorem states that continuous internal symmetries cannot be spo
ntaneously broken in two-dimensional quantum field theories (QFTs). I will
discuss under which conditions a similar result holds for two-dimensional
defects in CFTs invariant under a continuous symmetry group. I will argue
that spontaneous symmetry breaking is only possible for exotic RG flows\,
that do not terminate at a fixed point. I will present examples and descr
ibe a generic defect universality class\, formerly found by Metlitski for
boundaries in the O(N) model\, where correlation functions decay logarithm
ically at large distances.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Franceschini (University of Modena and Reggio Emilia\, Mode
na\, Italy)
DTSTART:20240227T130000Z
DTEND:20240227T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/38
DESCRIPTION:Title: Interacting particles systems out of equilibrium\nby Chiara Franc
eschini (University of Modena and Reggio Emilia\, Modena\, Italy) as part
of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIn this talk I p
lan to give an overview of a rich family of models that share several aspe
cts. In particular\, they are all related to each other by a common underl
ying algebraic description based on Lie Algebras. It is interesting to add
boundary reservoirs to place the systems out of equilibrium and thus stud
y the non-equilibrium stationary measure.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ngoc Nhi Nguyen (Department of Mathematics "Federigo Enriques"\, U
niversity of Milan\, Milano\, Italy)
DTSTART:20240312T123000Z
DTEND:20240312T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/39
DESCRIPTION:Title: Weyl laws for interacting particles\nby Ngoc Nhi Nguyen (Departme
nt of Mathematics "Federigo Enriques"\, University of Milan\, Milano\, Ita
ly) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nThe
known Weyl laws of Schrödinger operators provide asymptotics the ground s
tate density of systems of several non-interacting fermions submitted to a
n external potential . We will discuss the corresponding version in the ca
se of repulsive interactions between these particles.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jérémie Bouttier (IMJ - Sorbonne Université\, Paris\, France)
DTSTART:20240327T123000Z
DTEND:20240327T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/40
DESCRIPTION:Title: On the O(n) loop model on random maps\nby Jérémie Bouttier (IMJ
- Sorbonne Université\, Paris\, France) as part of Seed Seminar of Mathe
matics and Physics\n\nLecture held in Maryam Mirzakhani (a.k.a. Salle 201
on 2nd floor)\, Institut Henri Poincaré.\n\nAbstract\nMaps are discrete s
urfaces obtained by gluing polygons\, and form a natural model of random g
eometry. Of particular interest is the study of their large-scale properti
es\, which has been an active field of research for more than 25 years. A
major open question is the geometry of maps which are "decorated" by a sta
tistical physics model at a critical point. I will present some results ab
out a specific instance of such model\, namely the O(n) loop model on rand
om maps. Based on past and ongoing collaborations with G. Borot\, E. Guitt
er\, B. Duplantier\, G. Miermont and J. Turunen.\n\nPart of the kick-off e
vent of the seminar's spring 2024 thematic trimester on Integrable
systems\, at IHP (Paris). To attend in-person\, free but mandato
ry registration here.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Qianyu Hao (Section de Mathématiques - University of Geneva\, Swi
tzerland)
DTSTART:20240327T140000Z
DTEND:20240327T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/41
DESCRIPTION:Title: Abelianization of Virasoro conformal blocks at $c=1$\nby Qianyu H
ao (Section de Mathématiques - University of Geneva\, Switzerland) as par
t of Seed Seminar of Mathematics and Physics\n\nLecture held in Maryam Mir
zakhani (a.k.a. Salle 201 on 2nd floor)\, Institut Henri Poincaré.\n\nAbs
tract\nConformal blocks are essential objects to study in the 2d CFTs. The
y depend on the data of a vertex algebra $\\CV$\, a punctured Riemann surf
ace $C$\, and possible decorations inserted at the punctures. The Virasoro
conformal blocks are very interesting since they have many connections to
other areas of math and physics. In particular\, some very important Vira
soro conformal blocks at c=1 are also known to be tau functions of some in
tegrable system. I will describe a new way to construct Virasoro conformal
blocks at $c=1$. This is closely related to the idea of nonabelianization
in the study of $SL(N\,\\mathbb{C})$ connections by using $GL(1\,\\mathbb
{C})$ connection in the work of Gaiotto-Moore-Neitzke and Neitzke-Hollands
. I will talk about our work on relating the $c=1$ Virasoro conformal bloc
ks on $C$ to the "abelian" Heisenberg conformal blocks on a branched doubl
e cover of C. The main new idea in our work is the use of the spectral net
work on the surface $C$. The nonabelianization construction enables us to
study the harder to get Virasoro conformal blocks using the simpler abelia
n objects. This is joint work in progress with Andrew Neitzke.\n\nPart of
the kick-off event of the seminar's spring 2024 thematic trimester on Integrable systems\, at IHP (Paris). To attend in-person\, fr
ee but mandatory registration here.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudia Fevola (Centre INRIA de Saclay\, Palaiseau\, France)
DTSTART:20240327T153000Z
DTEND:20240327T160000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/42
DESCRIPTION:Title: Computational Algebraic Geometry for Feynman Integrals and their Sing
ularities\nby Claudia Fevola (Centre INRIA de Saclay\, Palaiseau\, Fra
nce) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nFey
nman integrals play a central role in particle physics in the theory of sc
attering amplitudes. In this talk\, I will show some examples of how the i
nterplay between algebro-geometric methods and fundamental physics problem
s leads to advances in both disciplines. In particular\, I will discuss ve
ctor spaces associated with a family of generalized Euler integrals and th
e study of their singular locus.\n\nPart of the kick-off event of the semi
nar's spring 2024 thematic trimester on Integrable systems\, at IHP (Paris). To attend in-person\, free but mandatory registration
here.\
n
LOCATION:https://researchseminars.org/talk/SeedSeminar/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Catherine Wolfram (Department of Mathematics\, MIT\, Cambridge\, U
SA)
DTSTART:20240423T130000Z
DTEND:20240423T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/43
DESCRIPTION:Title: The dimer model in 3D\nby Catherine Wolfram (Department of Mathem
atics\, MIT\, Cambridge\, USA) as part of Seed Seminar of Mathematics and
Physics\n\n\nAbstract\nA dimer tiling of $ \\mathbb{Z}^d $ is a collection
of edges such that every vertex is covered exactly once. In 2000\, Cohn\,
Kenyon\, and Propp showed that 2D dimer tilings satisfy a large deviation
s principle. In joint work with Nishant Chandgotia and Scott Sheffield\, w
e prove an analogous large deviations principle for dimers in 3D. A lot of
the results for dimers in two dimensions use tools and exact formulas (e.
g. the height function representation of a tiling or the Kasteleyn determi
nant formula) that are specific to dimension 2. I will explain how to form
ulate the large deviations principle in 3D\, show simulations\, and try to
give some intuition for why three dimensions is different from two. Time
permitting\, I will explain some of the ways that we use a smaller set of
tools (e.g. Hall’s matching theorem or a double dimer swapping operation
) in our arguments.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Niklas Affolter (Institute of Discrete Mathematics and Geometry\,
TU Wien\, Vienna\, Austria)
DTSTART:20240423T140000Z
DTEND:20240423T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/44
DESCRIPTION:Title: Discrete Integrability\, Dimers and Geometry\nby Niklas Affolter
(Institute of Discrete Mathematics and Geometry\, TU Wien\, Vienna\, Austr
ia) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nWe'l
l begin by explaining "discrete integrability" in the sense of multi-dimen
sional consistency. Discrete integrability is quite literally about the po
ssibility to "integrate" discrete equations or discrete dynamics. The dime
r model is about sampling perfect matchings on a graph\, where the probabi
lity of each perfect matching is proportional to a product of edge-weights
. We will see that the dimer model is discretely integrable. Finally\, we
consider discrete geometric maps\, to which we attach a dimer model. The m
aps also turn out to be discretely integrable\, and the dimer partition fu
nctions provide the invariants of (discrete) motions. Based on joint work
with Béatrice de Tilière\, Max Glick\, Paul Melotti\, Pasha Pylyavskyy a
nd Sanjay Ramassamy.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julien Roussillon (Aalto University\, Finland)
DTSTART:20240509T080000Z
DTEND:20240509T090000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/45
DESCRIPTION:Title: Degenerate conformal blocks for the $W_3$ algebra at $c=2$ and Specht
polynomials\nby Julien Roussillon (Aalto University\, Finland) as par
t of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIn this first
talk\, I will provide a gentle introduction to Conformal Field Theory and
conformal blocks in general\, and I will discuss the case where they satis
fy a system of PDEs known as BPZ equations. Then\, I will focus on a speci
al case where the PDEs are third order\, and I will present new solutions
in terms of the celebrated Specht polynomials. If time permits\, I will de
scribe a conjecture relating such solutions to scaling limits of probabili
ties in the triple dimer model recently constructed by Kenyon and Shi. Thi
s talk is based on joint work with Augustin Lafay.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Harini Desiraju (Mathematical Research Institute\, Sydney\, Austra
lia)
DTSTART:20240509T090000Z
DTEND:20240509T100000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/46
DESCRIPTION:Title: The correspondence between Painlevé equations and c=1 conformal bloc
ks\, and its generalisation\nby Harini Desiraju (Mathematical Research
Institute\, Sydney\, Australia) as part of Seed Seminar of Mathematics an
d Physics\n\n\nAbstract\nThis talk will start with an overview of the Pain
levé/CFT correspondence that was initiated by the seminal paper of Gamayu
n\, Iorgov\, Lisovyi. I will then motivate a generalisation of such a corr
espondence using the probabilistic construction of conformal blocks.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Victor Nador (IMPAN\, Cracow\, Poland)
DTSTART:20240529T120000Z
DTEND:20240529T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/47
DESCRIPTION:Title: Jack polynomials and b-deformed constellations\nby Victor Nador (
IMPAN\, Cracow\, Poland) as part of Seed Seminar of Mathematics and Physic
s\n\n\nAbstract\nThe generating series of weighted maps and its generaliza
tion to constellations both take a simple form using Schur functions. Its
extension to the non-oriented case admits a similar expression but for a d
ifferent family of symmetric functions\, the zonal polynomials. In both ca
ses\, the properties of these generating series can be studied from a wide
variety of viewpoints: representation theory\, combinatorial decompositio
n\, random matrices\, integrable hierarchies etc.. The Jack polynomial are
a one parameter deformation\, called the b-deformation\, which interpolat
es between the orientable and non-oriented cases. However\, the b-deformat
ion makes the study of the corresponding series more intricate as most of
the above tools have no counterpart in that framework.\n\nIn this talk\, I
will present some of the difficulties arising when studying the b-deforma
tion\, especially from a combinatorial viewpoint. I will define the b-defo
rmed analogue of constellations introduced by Chapuy and Dolega and I will
show how in the particular cases\, we can still extract a countable set o
f PDE analogous to the cut-and-join equation\, based on recent results obt
ained with V. Bonzom.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Houcine Ben Dali (IECL\, Université de Lorraine\, Nancy and IRIF\
, Université Paris-Cité\, France)
DTSTART:20240529T130000Z
DTEND:20240529T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/48
DESCRIPTION:Title: Differential equations for the series of hypermaps with control on th
eir full degree profile\nby Houcine Ben Dali (IECL\, Université de Lo
rraine\, Nancy and IRIF\, Université Paris-Cité\, France) as part of See
d Seminar of Mathematics and Physics\n\n\nAbstract\nWe consider generating
series of hypermaps with controlled degrees of vertices\, hyperedges and
faces. It is well known that under some particular specializations\, these
series satisfy the celebrated KP equations in the orientable case\, and B
KP equations in the non-orientable one. In this talk\, I present a family
of differential equations which characterizes the full generating series o
f hypermaps.\n\nI will give a first proof which works for a one parameter
deformation of the series of hypermaps related to Jack polynomials. This p
roof is based on a differential formula for Jack characters obtained in a
joint work with Maciej Dołęga. I will also present a combinatorial proo
f for the orientable case.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabiana De Cesare (IHÉS)
DTSTART:20241120T093000Z
DTEND:20241120T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/49
DESCRIPTION:Title: Exploring confinement in Anti-de Sitter space\nby Fabiana De Cesa
re (IHÉS) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstrac
t\nAnti-de Sitter space acts as an infra-red cutoff for asymptotically fre
e theories\, allowing interpolation between a weakly-coupled small-sized r
egime and a strongly-coupled flat-space regime. I will discuss this interp
olation in the context of Yang-Mills theories in AdS from the perspective
of boundary conformal theories and its implications for the confinement/de
confinement transition. We find indications that at the transition a singl
et scalar operator becomes marginal\, destabilizing the deconfined phase e
xisting at a small size and leading to a confined phase that smoothly conn
ects to flat space.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikolay Ebel (IHÉS)
DTSTART:20241120T110000Z
DTEND:20241120T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/50
DESCRIPTION:Title: Tensor Network Renormalization Group Maps and Their Fixed Points\
nby Nikolay Ebel (IHÉS) as part of Seed Seminar of Mathematics and Physic
s\n\n\nAbstract\nTensor network renormalization group (RG) is a powerful t
echnique providing great control over the renormalization group flow both
numerically and analytically. This talk will focus on the study of fixed p
oints of tensor network RG maps in the context of classical lattice models
(e.g.\, the Ising model). Studying fixed points allows one to retrieve in
formation about phase transitions in a system\, which motivates this resea
rch. I will first introduce basic tensor network concepts. Then\, I will p
resent some rigorous results about high- and low-temperature fixed points
of lattice spin models (based on arXiv:2107.11464\, 2210.06669\, and 2401.
04229). Finally\, I will discuss the recent development that may grant acc
ess to the critical fixed points of lattice systems (based on arXiv:2408.1
0312).\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nafiz Ishtiaque (IHÉS)
DTSTART:20241204T110000Z
DTEND:20241204T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/51
DESCRIPTION:Title: Kramers-Wannier Duality in Non-abelian Ising Models from SymTFT\n
by Nafiz Ishtiaque (IHÉS) as part of Seed Seminar of Mathematics and Phys
ics\n\n\nAbstract\nI will present a concrete construction of 2d Ising part
ition functions on lattice\, with non-abelian (more generally non-invertib
le) global symmetry. The construction realizes the Ising model as the boun
dary theory of a 3d symmetry topological field theory (SymTFT) with specif
ic boundary conditions. Suitable choices of boundary conditions correspond
to going to different topological sectors of the global symmetry or gaugi
ng arbitrary non-anomalous subsymmetry. Electric-magnetic type duality of
the SymTFT results in dual descriptions of the Ising model that generalize
s the Kramers-Wannier duality of Z/2Z symmetric Ising models.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Russo (Ecole Polytechnique)
DTSTART:20241204T093000Z
DTEND:20241204T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/52
DESCRIPTION:Title: Partial wave decomposition in thermal conformal field theories\nb
y Francesco Russo (Ecole Polytechnique) as part of Seed Seminar of Mathema
tics and Physics\n\n\nAbstract\nThe conformal block expansion of correlati
on functions is a fundamental tool in the bootstrap program. Block computa
tion can be related to a specific class of harmonic functions on the confo
rmal group. We generalize this concept to the case of thermal conformal fi
eld theories and compute one-point blocks for spinning representations in
three dimensions. Specifically\, we derive a universal Casimir equation an
d solve it using recursion relations. Finally\, we use the blocks in sever
al examples to explore some features of OPE coefficients.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioana Coman (IPMU)
DTSTART:20241218T110000Z
DTEND:20241218T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/54
DESCRIPTION:Title: Modularity and resurgence of topological 3-manifold invariants\nb
y Ioana Coman (IPMU) as part of Seed Seminar of Mathematics and Physics\n\
n\nAbstract\nA type of BPS q-series\, proposed recently as a topological i
nvariant which provides a non-perturbative completion of complex Chern-Sim
ons theory on closed 3-dimensional manifolds\, has mathematical definition
s based for example on 3D topology\, quantum groups and resurgence\, and k
ey properties their integrality and behaviour under surgery formulae. Thes
e q-series invariants have displayed relations to vertex operator algebras
\, and structurally\, they have intriguing modular properties. Their mathe
matical formulation is nevertheless quite constrained\, relying heavily on
certain negative-definite conditions\, and much effort has been devoted t
o extending this definition. This operation is called “going to the othe
r side”\, with different interpretations from the physics\, vertex algeb
ra\, and 3D topology perspectives. I will discuss different approaches to
this challenge\, in particular through modularity and resurgence\, with im
plications for the related vertex operator algebras.\n\nonline\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bertrand Duplantier (Institut de Physique Théorique\, CEA Saclay\
, Université Paris-Saclay)
DTSTART:20250212T123000Z
DTEND:20250212T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/55
DESCRIPTION:Title: Hamiltonian Paths on Random Planar Maps\nby Bertrand Duplantier (
Institut de Physique Théorique\, CEA Saclay\, Université Paris-Saclay) a
s part of Seed Seminar of Mathematics and Physics\n\nLecture held in Amphi
Choquet-Bruhat (batiment Perrin)\, Institut Henri Poincaré\, Paris.\n\nA
bstract\nHamiltonian paths are self-avoiding random walks that visit all s
ites of a given lattice. We consider various configuration exponents of Ha
miltonian walks drawn on random planar maps. Estimates from exact enumerat
ions are compared with predictions based on the Knizhnik-Polyakov-Zamolodc
hikov (KPZ) relations\, as applied to exponents on the regular hexagonal l
attice. Astonishingly\, when the maps are bipartite\, a naive use of KPZ d
oes not reproduce all the measured exponents\, but an Ansatz may possibly
account for the observed discrepancies. We further study Hamiltonian cycle
s on various families of bipartite planar maps\, which fall into two unive
rsality classes\, with respective central charges c = -1 or c = -2. The fi
rst group comprises maps of fixed vertex valency p larger than 3\, whereas
the second group involves maps with mixed vertex valencies\, as well as a
so-called rigid case. For each class\, a universal configuration exponent
and a novel critical exponent associated with long-distance contacts alon
g a Hamiltonian cycle are predicted from KPZ and the corresponding exponen
t on regular (hexagonal or square) lattices. This time\, the KPZ predictio
ns are numerically confirmed by exact enumeration results for p-regular ma
ps\, with p = 3\, 4\, 5\, 6\, 7\, and for maps with mixed valencies (2\,3)
and (2\,4). The scaling limit of fully-packed systems thus poses intrigui
ng unresolved questions from both the Liouville Quantum Gravity and the Sc
hramm-Loewner Evolution perspectives. Based on joint works with Ph. Di Fra
ncesco\, O. Golinelli and E. Guitter.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yizheng Yuan (Statistical Laboratory\, Cambridge University\, UK)
DTSTART:20250212T140000Z
DTEND:20250212T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/56
DESCRIPTION:Title: The chemical distance metric for non-simple CLE\nby Yizheng Yuan
(Statistical Laboratory\, Cambridge University\, UK) as part of Seed Semin
ar of Mathematics and Physics\n\nLecture held in Amphi Choquet-Bruhat (bat
iment Perrin)\, Institut Henri Poincaré\, Paris.\n\nAbstract\nWe construc
t the continuum analogue of the chemical distance metric in\nlattice model
s such as percolation. The chemical distance metric is the\ngraph distance
induced by the percolation clusters. It is known that for\ncritical perco
lation\, the lengths have non-trivial scaling behaviour\,\nhowever it is v
ery difficult to find the exact scaling exponent. (This\nis one of the que
stions from Schramm's ICM 2006 article that remains\nunsolved.)\n\nIn a jo
int work with Valeria Ambrosio and Jason Miller\, we construct a\nchemical
distance metric on the CLE gasket for each $\\kappa \\in ]4\,8[$. We\nsho
w that it is unique metric that is geodesic\, Markovian\, and\nconformally
covariant. The characterisation is reminiscent of the LQG\nmetric\, but o
ur objects behave very differently\, and hence our\ntechniques also differ
significantly from those used in LQG. For\n$\\kappa=6$\, we conjecture th
at our random metric space is the scaling\nlimit of critical percolation.\
n
LOCATION:https://researchseminars.org/talk/SeedSeminar/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Léonie Papon (Durham University\, UK)
DTSTART:20250212T153000Z
DTEND:20250212T163000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/57
DESCRIPTION:Title: Interface scaling limit for the critical planar Ising model perturbed
by a magnetic field\nby Léonie Papon (Durham University\, UK) as par
t of Seed Seminar of Mathematics and Physics\n\nLecture held in Amphi Choq
uet-Bruhat (batiment Perrin)\, Institut Henri Poincaré\, Paris.\n\nAbstra
ct\nIn this talk\, I will consider the interface separating +1 and -1 spin
s in the critical planar Ising model with Dobrushin boundary conditions pe
rturbed by an external magnetic field. I will prove that this interface ha
s a scaling limit. This result holds when the Ising model is defined on a
bounded and simply connected subgraph of $\\delta\\mathbb{Z}^2$\, with $\\
delta > 0$. I will show that if the scaling of the external field is of or
der $\\delta^{15/8}$\, then\, as $\\delta \\to 0$\, the interface converge
s in law to a random curve whose law is conformally covariant and absolute
ly continuous with respect to $\\text{SLE}_3$. This limiting law is a mass
ive version of $\\text{SLE}_3$ in the sense of Makarov and Smirnov and I w
ill give an explicit expression for its Radon-Nikodym derivative with resp
ect to $\\text{SLE}_3$. I will also prove that if the scaling of the exter
nal field is of order $\\delta^{15/8}g(\\delta)$ with $g(\\delta) \\to 0$\
, then the interface converges in law to $\\text{SLE}_3$. In contrast\, I
will show that if the scaling of the external field is of order $\\delta^{
15/8}f(\\delta)$ with $f(\\delta) \\to \\infty$\, then the interface degen
erates to a boundary arc.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul Roux (École Normale Supérieure\, Paris\, France)
DTSTART:20250226T093000Z
DTEND:20250226T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/58
DESCRIPTION:Title: Combinatorial maps in critical loop model\nby Paul Roux (École N
ormale Supérieure\, Paris\, France) as part of Seed Seminar of Mathematic
s and Physics\n\nLecture held in Amphithéâtre Léon Motchane\, IHÉS.\n\
nAbstract\nLoop models are a class of statistical lattice models whose cor
relation functions can be interpreted geometrically\, as sums over configu
rations of non-intersecting loops. In the critical limit\, the observables
of these models are described by a Conformal Field Theory (CFT)\, which i
s believed to be exactly solvable. In this talk\, we will shortly review w
hat are loop models and present recent results showing that their correlat
ion functions are related to combinatorial objects called combinatorial ma
ps. Then\, we will relate the counting of certain maps on the torus to par
ticular classes of maps on the sphere\, and explain the CFT interpretation
of this mapping.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alicia Castro (Laboratoire Bordelais de Recherche en Informatique
(LaBRI)\, France)
DTSTART:20250226T110000Z
DTEND:20250226T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/59
DESCRIPTION:Title: Critical JT Gravity\nby Alicia Castro (Laboratoire Bordelais de R
echerche en Informatique (LaBRI)\, France) as part of Seed Seminar of Math
ematics and Physics\n\nLecture held in Amphithéâtre Léon Motchane\, IH
ÉS.\n\nAbstract\nIn this talk\, I will present JT gravity\, a model of tw
o-dimensional quantum gravity on constant negatively curved spacetimes\, a
s a model of random hyperbolic surfaces. By studying the generating functi
on of volumes of random hyperbolic surfaces with defects\, i.e. weighted g
eodesic boundaries\, we explore critical regimes where the surfaces develo
p macroscopic holes. This is reminiscent of the $O(N)$ model for random ma
ps. We analyse the impact of this critical behavior on the density of stat
es of the theory at the boundary\, and we present a family of models that
interpolate between systems with $\\sqrt{E}$ and $E^{3/2}$\, which are com
monly found in models of JT Gravity coupled to dynamical end-of-the-world
and FZZT branes.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:William Da Silva (University of Vienna\, Austria)
DTSTART:20250312T093000Z
DTEND:20250312T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/60
DESCRIPTION:Title: The scaling limit of the volume of loop-O(n) quadrangulations\nby
William Da Silva (University of Vienna\, Austria) as part of Seed Seminar
of Mathematics and Physics\n\nLecture held in Amphithéâtre Léon Motcha
ne.\n\nAbstract\nWe study the volume of rigid loop-O(n) quadrangulations w
ith a boundary of length 2p in the critical non-generic regime. We prove t
hat\, as the half-perimeter p goes to infinity\, the volume scales in dist
ribution to an explicit random variable. This limiting random variable is
described in terms of the multiplicative cascades of Chen\, Curien and Mai
llard\, or alternatively (in the dilute case) as the law of the area of a
suitable unit-boundary quantum disc\, as determined by Ang and Gwynne. Our
arguments go through a classification of the map into several regions\, w
here we rule out the contribution of bad regions to be left with a tractab
le portion of the map. One key observable for this classification is a Mar
kov chain which explores the nested loops around a size-biased vertex pick
in the map\, making explicit the spinal structure of the discrete multipl
icative cascade. This talk is based on joint work with Élie Aïdékon and
XingJian Hu (Fudan University).\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vlad Margarint (University of North Carolina Charlotte\, USA)
DTSTART:20250312T110000Z
DTEND:20250312T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/61
DESCRIPTION:Title: A bridge between Random Matrix Theory and Schramm-Loewner Evolutions<
/a>\nby Vlad Margarint (University of North Carolina Charlotte\, USA) as p
art of Seed Seminar of Mathematics and Physics\n\nLecture held in Amphith
éâtre Léon Motchane.\n\nAbstract\nI will describe a newly introduced to
olbox that connects two areas of Probability Theory: Schramm-Loewner Evolu
tions (SLE) and Random Matrix Theory. This machinery opens new avenues of
research that allow the use of techniques from one field to another. One a
spect of this research direction is centered in an interacting particle sy
stems model\, namely the Dyson Brownian motion. In the first part of the t
alk\, I will introduce basic ideas of SLE theory\, then I will describe th
e connection with Random Matrix Theory via a first application of our meth
od. I will finish the talk with some open problems that emerge using this
newly introduced toolbox. This is a joint work with A. Campbell and K. Luh
.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenzo Dello Schiavo (Università degli Studi di Roma "Tor Vergat
a")
DTSTART:20250326T093000Z
DTEND:20250326T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/62
DESCRIPTION:Title: Conformally invariant random fields\, quantum Liouville measures\, an
d random Paneitz operators on Riemannian manifolds of even dimension\n
by Lorenzo Dello Schiavo (Università degli Studi di Roma "Tor Vergata") a
s part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nOn large
classes of closed even-dimensional Riemannian manifolds M\, we construct a
nd study the Copolyharmonic Gaussian Field\, i.e. a conformally invariant
log-correlated Gaussian field of distributions on M. This random field is
defined as the unique centered Gaussian field with covariance kernel given
as the resolvent kernel of Graham—Jenne—Mason—Sparling (GJMS) opera
tors of maximal order. The corresponding Gaussian Multiplicative Chaos is
a generalization to the 2m-dimensional case of the celebrated Liouville Qu
antum Gravity measure in dimension two. We study the associated Liouville
Brownian motion and random GJMS operator\, the higher-dimensional analogue
s of the 2d Liouville Brownian Motion and of the random Laplacian. Finally
\, we study the Polyakov–Liouville measure on the space of distributions
on M induced by the copolyharmonic Gaussian field\, providing explicit co
nditions for its finiteness and computing the conformal anomaly.\nJ. Londo
n Math. Soc. (2) 2024:110\, 1-80\, joint work with Ronan Herry\, Eva Kopfe
r\, Karl-Theodor Sturm.\n\nOnly online\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Liam Hughes
DTSTART:20250326T110000Z
DTEND:20250326T120000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/63
DESCRIPTION:Title: Embeddability of Liouville quantum gravity metrics\nby Liam Hughe
s as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIntrod
uced by Polyakov in the 1980s\, Liouville quantum gravity (LQG) is in some
sense the canonical model of a random fractal Riemannian surface. LQG can
be defined as a path integral over fields corresponding to the Liouville
action\, or equivalently as a random metric measure space that turns out t
o describe the scaling limit of a host of two-dimensional discrete objects
. In particular\, certain discrete conformal embeddings of random planar m
aps converge to canonical (up to conformal reparametrization) embeddings o
f LQG surfaces into 2D Euclidean space. Though one might expect these metr
ic embeddings to retain some vestige of conformality\, in fact no embeddin
g of an LQG surface into R^n can be quasisymmetric. This generalizes a res
ult of Troscheit in the special case of sqrt(8/3)-LQG (corresponding to un
iform random planar maps). Time permitting\, I will also discuss future di
rections in the study of metric embeddability for LQG.\n\nOnly online\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolas Curien (LMO\, Université Paris-Saclay)
DTSTART:20250425T080000Z
DTEND:20250425T090000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/64
DESCRIPTION:Title: Universality of fully parked trees and catalytic equations\nby Ni
colas Curien (LMO\, Université Paris-Saclay) as part of Seed Seminar of M
athematics and Physics\n\nLecture held in Institut Pascal.\n\nAbstract\nWe
show that critical parking trees conditioned to be fully parked converge
in the scaling limits towards the Brownian growth-fragmentation tree\, a s
elf-similar Markov tree different from Aldous’ Brownian tree. As a by-pr
oduct of our study\, we prove that positive non-linear functional equation
s involving a catalytic variable display a universal polynomial exponent 5
/2 at their singularity\, confirming a conjecture by Chapuy\, Schaeffer an
d Drmota & Hainzl. Compared to previous analytical works on the subject\,
our approach is probabilistic and exploits an underlying random walk hidde
n in the random tree model. Joint work with Alice Contat.\n\nThis talk is
part of the "SEED Annual Workshop". To attend this event please register a
t https://indico.ijclab.in2p3.fr/event/11715/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Boris Pioline (LPTHE\, Sorbonne Université))
DTSTART:20250425T091500Z
DTEND:20250425T101500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/65
DESCRIPTION:Title: Modularity of enumerative invariants on Calabi-Yau threefolds\nby
Boris Pioline (LPTHE\, Sorbonne Université)) as part of Seed Seminar of
Mathematics and Physics\n\nLecture held in Institut Pascal.\n\nAbstract\nM
odularity of enumerative invariants on Calabi-Yau threefolds\n Apr 25\, 20
25\, 11:15 AM\n 1h\n small Amphitheater\nSpeaker\n Boris Pioline (LPTHE\
, Sorbonne Université)\nDescription\nOnce put into suitable generating se
ries\, various enumerative invariants on Calabi-Yau threefolds are expecte
d to possess modular properties\, allowing to determine them uniquely from
a few data points and giving powerful control on their asymptotic growth.
This includes Gromov-Witten invariants in presence of a genus one fibrati
on\, Noether-Lefschetz invariants in presence of a K3 fibration\, as well
as Donalson-Thomas invariants supported on divisors (without requiring any
particular fibration). While modularity has a clear mathematical origin i
n the first two cases\, it is more mysterious in the last case\, correspon
ding physically to BPS indices counting D4-D2-D0 black holes. I will revie
w recent progress in testing the modularity (or more generally mock modula
rity) of D4-D2-D0 indices in one-parameter Calabi-Yau threefolds such as t
he quintic threefold\, and in leveraging these results to compute Gopakuma
r-Vafa invariants at higher genus than hitherto possible. Based on work in
collaboration with Sergey Alexandrov\, Soheyla Feyzbakhsh\, Albrecht Klem
m and Thorsten Schimannek.\n\nThis talk is part of the "SEED Annual Worksh
op". To attend this event please register at https://indico.ijclab.in2p3.f
r/event/11715/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clément Delcamp (IHÉS)
DTSTART:20250425T120000Z
DTEND:20250425T130000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/66
DESCRIPTION:Title: Entanglement and renormalisation of spin systems in the generalised L
andau paradigm\nby Clément Delcamp (IHÉS) as part of Seed Seminar of
Mathematics and Physics\n\nLecture held in Institut Pascal.\n\nAbstract\n
Invoking results from topological quantum field theory\, I will demonstrat
e that for every spin system representing a symmetric gapped phase\, one c
an find a dual physical system whose dual symmetry is spontaneously broken
. I will argue that this result has strong implications for the classical
simulation of spin systems using variational tensor network methods\, as t
his dual physical system minimises both the entanglement entropy and the r
equired number of variational parameters. The applicability of this method
will be demonstrated by introducing a generalised Density Matrix Renormal
isation Group algorithm.\n\nThis talk is part of the "SEED Annual Workshop
". To attend this event please register at https://indico.ijclab.in2p3.fr/
event/11715/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/66/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Balt Van Rees (CPhT\, École polytechnique)
DTSTART:20250425T131500Z
DTEND:20250425T141500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/67
DESCRIPTION:Title: Theorems for the modular and lightcone bootstrap\nby Balt Van Ree
s (CPhT\, École polytechnique) as part of Seed Seminar of Mathematics and
Physics\n\nLecture held in Institut Pascal.\n\nAbstract\nWe consider the
implications of modular invariance for the spectrum of two-dimensional CFT
s. For states with high energy this question was analyzed at a qualitative
level by Cardy in 1986\, but rigorous statements were almost entirely abs
ent until the analysis (based on Tauberian theorems) by Mukhametzhanov and
Zhiboedeov in 2019. In this talk we consider states with a very large spi
n\, for which we show that it is possible to obtain much stronger rigorous
results. Using complex analysis we in particular demonstrate that the spe
ctrum of twists necessarily becomes dense for every large spin. We analyze
the size of the subleading corrections\, which will allow us to estimate
how rapidly the maximal spacing between operators goes to zero. An entirel
y analogous procedure can be applied to four-point functions of identical
operators in CFTs with a twist gap.\n\nTalk based on work in progress with
Sridip Pal and Jiaxin Qiao.\n\nThis talk is part of the "SEED Annual Work
shop". To attend this event please register at https://indico.ijclab.in2p3
.fr/event/11715/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stavros Garoufalidis (ICM-SUSTech\, and IHÉS)
DTSTART:20250425T143000Z
DTEND:20250425T153000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/68
DESCRIPTION:Title: What can the gluing equation matrices tell us about a 3-manifold?
\nby Stavros Garoufalidis (ICM-SUSTech\, and IHÉS) as part of Seed Semina
r of Mathematics and Physics\n\nLecture held in Institut Pascal.\nAbstract
: TBA\n\nThis talk is part of the "SEED Annual Workshop". To attend this e
vent please register at https://indico.ijclab.in2p3.fr/event/11715/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ellen Saada (CNRS & MAP5\, Université Paris-Cité\, France)
DTSTART:20250604T113000Z
DTEND:20250604T123000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/69
DESCRIPTION:Title: The two-lane exclusion process\nby Ellen Saada (CNRS & MAP5\, Uni
versité Paris-Cité\, France) as part of Seed Seminar of Mathematics and
Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierluigi Niro (SISSA\, Trieste\, Italy)
DTSTART:20250604T130000Z
DTEND:20250604T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/70
DESCRIPTION:Title: Symmetry breaking in 3d QED\nby Pierluigi Niro (SISSA\, Trieste\,
Italy) as part of Seed Seminar of Mathematics and Physics\n\nAbstract: TB
A\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas D'Alimonte (LPSM\, Sorbonne Université\, Paris\, France)
DTSTART:20250604T143000Z
DTEND:20250604T153000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/71
DESCRIPTION:Title: Ornstein—Zernike theory for the near-critical planar random cluster
model\nby Lucas D'Alimonte (LPSM\, Sorbonne Université\, Paris\, Fra
nce) as part of Seed Seminar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xia Jiaming (IHES)
DTSTART:20250611T100000Z
DTEND:20250611T110000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/72
DESCRIPTION:Title: Extract one-arm exponent in FK models from the convergence of height
functions to GFF\nby Xia Jiaming (IHES) as part of Seed Seminar of Mat
hematics and Physics\n\nLecture held in IHES\, Amphithéâtre Léon Motcha
ne.\n\nAbstract\nWe consider FK models with q in [0\,4] on the square latt
ice and the whole plane. We assume the convergence of height functions to
GFF and in particular we assume that we know the variance σ2 of the GFF.
Then\, we sketch an approach to get the exponent α1 describing the probab
ility of having a primal crossing of an annulus. The basis for this approa
ch is the BKW coupling relating the height function to the interface loops
of FK. We show that by choosing appropriate test functions (viewed as pla
cing charges on the plane)\, we can get relations between σ2\, α1\, and
a factor accounting for local concentration of small interface loops.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Orphée Collin (LPSM\, Université Paris-Cité\, France)
DTSTART:20250618T083000Z
DTEND:20250618T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/73
DESCRIPTION:Title: The Random Field Ising Chain in the case of centered disorder\nby
Orphée Collin (LPSM\, Université Paris-Cité\, France) as part of Seed
Seminar of Mathematics and Physics\n\nLecture held in IHES\, Amphithéâtr
e Léon Motchane.\n\nAbstract\nOur understanding of the behaviors appearin
g in statistical physics has been built firstly on the well-known Ising Mo
del. Here\, we will consider a disordered version of the one-dimensional I
sing model: we will present and study the ferromagnetic Ising model on a l
ine graph interacting with an external magnetic field\, sampled from an i.
i.d. distribution. We will be interested in the regime where the intensity
of the disorder is fixed and the spin-spin interaction goes to infinity.\
n\nWe will also introduce a continuous version of the model\, which natura
lly arises from a weak disorder limit. For this continuous model\, various
quantities (such as the free energy) can be computed explicitely\, thus y
ielding precise information on the typical configurations of the system.\n
\nThe free energy of the discrete model can easily be expressed as the Lya
punov exponent of a random product of 2x2 matrices\, which we estimate usi
ng Furstenberg’s theory: we will present recent results on the asymptoti
cs of the free energy\, in the regime we consider.\n\nFurthermore\, in bot
h the discrete and the continuous models\, we will characterize the behavi
our of the system at the level of configurations. In agreement with predic
tions in the physics literature\, we will show that the configurations are
typically close to one given configuration\, determined by the environmen
t (the external field)\, thus showing that the disorder is strongly releva
nt.\n\nOur discussion will concern mainly the critical case\, i.e.\, the c
ase where the disorder is centered\, but we may also address the non-criti
cal case.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sara Murciano (LPTMS\, Université Paris-Saclay\, Orsay\, France)
DTSTART:20250618T100000Z
DTEND:20250618T110000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/74
DESCRIPTION:Title: Observable-projected ensemble\nby Sara Murciano (LPTMS\, Universi
té Paris-Saclay\, Orsay\, France) as part of Seed Seminar of Mathematics
and Physics\n\nLecture held in IHES\, Amphithéâtre Léon Motchane.\n\nAb
stract\nLocal measurements in many‐body quantum systems can produce surp
rising phenomena—from preparing long‐range entangled states to driving
measurement‐induced phase transitions and modifying critical behavior.
In this talk\, I will introduce a new “observable‐projected” protoco
l: rather than performing complete projective measurements on the compleme
nt of a subsystem\, we measure a single\, local Hermitian operator on part
of that complement. The result is a mixed‐state ensemble on the subsyst
em that remains analytically tractable within a conformal field theory fra
mework. I will then show how this ensemble’s entanglement structure can
be computed\, and present a detailed case study of the free compact boson.
\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessio Lerose (Department of Physics and Astronomy\, KU Leuven)
DTSTART:20250611T083000Z
DTEND:20250611T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/76
DESCRIPTION:Title: Thermalization and ergodicity breaking in quantum many-body systems\nby Alessio Lerose (Department of Physics and Astronomy\, KU Leuven) as
part of Seed Seminar of Mathematics and Physics\n\nLecture held in Online
and streamed at Amphithéâtre Léon Motchane.\n\nAbstract\nNon-equilibri
um dynamics of isolated quantum many-body systems plays an important role
in contemporary theoretical physics research\, from foundational questions
on quantum statistical mechanics to the development of quantum technologi
es.\n\nI will provide a guided tour of a selection of results on thermaliz
ation and ergodicity breaking in quantum many-body dynamics\, with an eye
on mathematically rigorous studies\, including (many) conjectures and (few
) proven statements.\n\nOnline talk. It will be streamed at IHES. To get t
he link\, please register at https://seedseminar.apps.math.cnrs.fr/\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Philine van Vliet (LPTENS\, École Normale Supérieure)
DTSTART:20250709T073000Z
DTEND:20250709T083000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/77
DESCRIPTION:Title: 1d Long-range Ising model near the short-range crossover\nby Phil
ine van Vliet (LPTENS\, École Normale Supérieure) as part of Seed Semina
r of Mathematics and Physics\n\nLecture held in IHES\, Amphithéâtre Léo
n Motchane.\n\nAbstract\nOne of the features of the critical behavior of t
he long-range Ising model (LRI) with interactions decaying as $1/r^{s+d}$
is that it has a line of interacting fixed points\, and hence corresponds
to a family of interacting $d$-dimensional CFT\, for $d/2 < s < s_{*}$. Bo
th ends of this range of $s$ admit a weakly-coupled description. For small
$s$\, the theory is described as a generalized free field with a $\\phi^{
4}$ interaction. For large $s$\, the theory can be described by the $d$-di
mensional short-range Ising model (SRI) coupled to a generalized free fiel
d. While these descriptions have been used to study the LRI in dimensions
$d>1$\, in $d=1$ it leads to a fascinating puzzle. The $1d$ LRI still has
a line of interacting fixed points for $1/2Lipschitz continuity of diffusion transport maps from a control persp
ective\nby Katharina Eichinger (LMO\, Paris-Saclay and Inria ParMA) as
part of Seed Seminar of Mathematics and Physics\n\nLecture held in IHES\,
Amphithéâtre Léon Motchane.\n\nAbstract\nLipschitz transport maps betw
een two measures are useful tools for transferring analytical properties\,
such as functional inequalities. The most well-known result in this field
is Caffarelli’s contraction theorem\, which shows that the optimal tran
sport map from a Gaussian to a uniformly log-concave measure is globally L
ipschitz. Note that the transfer of analytical properties does not depend
on the optimality of the transport map. This is why several works have est
ablished Lipschitz bounds for other transport maps\, such as those derived
from diffusion processes\, as introduced by Kim and Milman. Here\, we use
the control interpretation of the transport vector field inducing the tra
nsport map and a coupling strategy to obtain Lipschitz bounds for this map
between asymptotically log-concave measures and their Lipschitz perturbat
ions. This talk is based on a joint work with Giovanni Conforti.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fanny Eustachon (CPhT\, École polytechnique)
DTSTART:20250709T100000Z
DTEND:20250709T110000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/79
DESCRIPTION:Title: The effective field theory realizations of the perfect fluid\nby
Fanny Eustachon (CPhT\, École polytechnique) as part of Seed Seminar of M
athematics and Physics\n\nLecture held in IHES\, Amphithéâtre Léon Motc
hane.\n\nAbstract\nHydrodynamics is one of the oldest example of field the
ories\, describing the long-range behaviour of many-body systems and its s
tudy remained mostly classical. Nevertheless\, near zero temperature\, qua
ntum fluctuations grow in importance raising the natural question: is ther
e a consistent quantum picture of a perfect fluid at zero temperature?\n\n
In this talk\, I will review the subtly inequivalent Lagrangians realizati
ons of the perfect fluid through the lens of modern effective field theory
(EFT). I will then discuss its particularity\, naming the presence of an
infinitely dimensional symmetry. As we will see\, its main implication is
the existence of transverse modes with vanishing dispersion relation at th
e classical level\, and an infinitely degenerate spectrum and UV-IR mixing
at the quantum level.\n\nThis is based on a work with G. Cuomo\, E. Firat
\, B. Henning and R. Rattazzi https://arxiv.org/abs/2412.10344.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Sportiello (CNRS and LIPN\, Université Sorbonne Paris Nord
)
DTSTART:20251029T123000Z
DTEND:20251029T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/80
DESCRIPTION:Title: Grassmann Calculus for the combinatorics of Spanning Trees and Forest
s\nby Andrea Sportiello (CNRS and LIPN\, Université Sorbonne Paris No
rd) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIn t
his talk we will make a survey of how techniques of ``Grassmann\nCalculus'
'\, that is\, integration of expressions involving\nanticommuting variable
s\, provide fermionic analogues of Gaussian\nintegration\, Wick's Theorem
and perturbative field theory. These\ntechniques are specially fruitful fo
r describing certain combinatorial\nmodels in Statistical Mechanics\, name
ly $n=2$ Loop Models\, Spanning\nTrees\, and Spanning Forests.\n\nIf the t
ime permits\, we will also show how the model of Spanning\nForests\, in it
s Grassmann-variable formulation\, has a hidden ${\\mathrm{OSp}}(1\\vert 2
)$ supersymmetry\, that\, by the Parisi--Sourlas\nmechanism\, implies that
it must be in the same universality class of\nthe $O(n)$ loop model in th
e analytic continuation $n\\to -1$.\n\nMostly based on (old) works in coll
aboration with S. Caracciolo and\nA.D. Sokal.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julien Weibel (INRIA & ENS Paris)
DTSTART:20251029T153000Z
DTEND:20251029T163000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/81
DESCRIPTION:Title: Probability-graphons: limits for sequences of large dense weighted gr
aphs\nby Julien Weibel (INRIA & ENS Paris) as part of Seed Seminar of
Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Camille Cazaux (LPSM)
DTSTART:20251126T104500Z
DTEND:20251126T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/82
DESCRIPTION:Title: Limiting Degree Distribution for a Sublinear Preferential Attachment
Model with Communities\nby Camille Cazaux (LPSM) as part of Seed Semin
ar of Mathematics and Physics\n\n\nAbstract\nFor many real-world networks\
, such as the World Wide Web\, the degree distribution follows a power law
. It is therefore useful to have simple random graph models whose limiting
degree distribution exhibits this same feature. With this motivation\, ph
ysicists Albert-László Barabási and Réka Albert introduced the prefere
ntial attachment model that now bears their name. A further advantage of t
his model is that it incorporates temporal dynamics: starting from an init
ial graph $\\mathcal{G}_0$\, the graph at time $n+1$ is obtained from the
graph at time $n$\, denoted $\\mathcal{G}_n$\, by adding a new vertex $v_{
n+1}$. This vertex then attaches to one or several vertices of $\\mathcal{
G}_n$ according to a preferential attachment rule\, meaning that the proba
bility of connecting to a given vertex of $\\mathcal{G}_n$ is proportional
to its degree.\n\nWe present an extension of this model in which each ver
tex of the graph is assigned a community (or type)\, and in which the pref
erential attachment is sublinear\; that is\, the probability of attaching
to a vertex $u$ is proportional to $\\deg(u)^\\gamma$\, where $\\gamma$ is
a parameter taking values in $(0\,1)$.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/82/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jesper Jacobsen (LPTENS)
DTSTART:20251210T093000Z
DTEND:20251210T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/89
DESCRIPTION:Title: Three-point functions in critical loop models\nby Jesper Jacobsen
(LPTENS) as part of Seed Seminar of Mathematics and Physics\n\n\nAbstract
\nIn two-dimensional models of critical non-intersecting loops\, we conjec
ture an exact formula for three-point functions of fields that insert legs
(open loop segments) and can have nonzero conformal spin. The conjecture
extends a previous result for diagonal fields\, recently proved by Ang-Cai
-Sun-Wu\, who also proved our conjecture for three spinless two-leg operat
ors. We discuss in details the supporting evidence for our general conject
ure coming from transfer-matrix computations using the unoriented Jones-Te
mperley-Lieb algebra.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sonia Boulal (Institut Denis Poisson Université d’Orléans)
DTSTART:20251029T140000Z
DTEND:20251029T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/90
DESCRIPTION:Title: Conditioned Marked Galton-Watson trees\nby Sonia Boulal (Institut
Denis Poisson Université d’Orléans) as part of Seed Seminar of Mathem
atics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giuseppe Scola (UNICAL (Università della Calabria))
DTSTART:20251126T093000Z
DTEND:20251126T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/91
DESCRIPTION:Title: Point of a ψ^4_d Fermionic Theory: Anomalous Exponent and Scaling Op
erators\nby Giuseppe Scola (UNICAL (Università della Calabria)) as pa
rt of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nWe consider t
he Renormalization Group (RG) fixed-point theory associated with a fermion
ic $\\psi^4_d$ model in $d= 1\, 2\, 3$ with fractional kinetic term\, whos
e scaling dimension is fixed so that the quartic interaction is weakly rel
evant in the RG sense. The model is defined in terms of a Grassmann functi
onal integral with interaction V*\, solving a fixed-point RG equation in t
he presence of external fields\, and a fixed ultraviolet cutoff. We define
and construct the field and density scale-invariant response functions\,
and prove that the critical exponent of the former is the naive one\, whil
e that of the latter is anomalous and analytic. We construct the correspon
ding (almost-)scaling operators\, whose two point correlations are scale-i
nvariant up to a remainder term\, which decays like a stretched exponentia
l at distances larger than the inverse of the ultraviolet cutoff. Our proo
f is based on constructive RG methods and\, specifically\, on a convergent
tree expansion for the generating function of correlations\, which genera
lizes the approach developed by three of the authors in a previous publica
tion (Giuliani et al. in JHEP 01:026\, 2021. https://doi.org/10.1007/JHEP0
1(2021)026). \nCMP 406.10 (2025): 257\, joint work with A. Giuliani\, V. M
astropietro and S. Rychkov.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vincent Viau (LAGA\, USPN)
DTSTART:20251112T130000Z
DTEND:20251112T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/92
DESCRIPTION:Title: Supercritical frozen Erdős-Rényi and uniform random forests\nby
Vincent Viau (LAGA\, USPN) as part of Seed Seminar of Mathematics and Phy
sics\n\n\nAbstract\nThe frozen Erdős-Rényi random graph is a variant of
the standard dynamical Erdős-Rényi random graph that prevents the creati
on of the giant component by freezing the evolution of connected component
s with a unique cycle. The formation of multicyclic components is forbidde
n\, and the growth of components with a unique cycle is slowed down\, depe
nding on a parameter $p\\in[0\, 1]$ that quantifies the slowdown. In this
talk\, we will study the fluid limit of the main statistics of this proces
s\, that is their functional convergence as the number of vertices of the
graph becomes large and after a proper rescaling\, to the solution of a sy
stem of differential equations. The proof is based on the free forest prop
erty of the frozen model: the forest part of the graph is a uniform random
forest. In order to prove the fluid limit results\, we will explain how t
o study and count forests using conditioned random walks.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/92/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vladimir Narovlansky (School of Natural Sciences\, IAS)
DTSTART:20251112T141500Z
DTEND:20251112T151500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/93
DESCRIPTION:Title: Dualities between fermionic theories and the Potts model\nby Vlad
imir Narovlansky (School of Natural Sciences\, IAS) as part of Seed Semina
r of Mathematics and Physics\n\n\nAbstract\nWe show that a large class of
fermionic theories are dual to a $q\\to 0$ limit of the Potts model in the
presence of a magnetic field. These can be described using a statistical
model of random forests on a graph\, generalizing the (unrooted) random fo
rest description of the Potts model with only nearest neighbor interaction
s. We then apply this to find a statistical description of a recently intr
oduced family of $OSp(1|2M)$ invariant field theories that provide a UV co
mpletion to sigma models with the same symmetry.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Rey (DMA\, ENS)
DTSTART:20251210T104500Z
DTEND:20251210T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/94
DESCRIPTION:Title: The near-critical dimer model and the sine-Gordon field\nby Lucas
Rey (DMA\, ENS) as part of Seed Seminar of Mathematics and Physics\n\n\nA
bstract\nThe study of critical models is of the more active areas of stati
stical mechanics. Regarding the dimer model\, the convergence of the criti
cal model towards the Gaussian free field was obtained around 25 years ago
by Kenyon. More recently\, perturbations of the critical model known as n
ear-critical models have been considered\, and some convergence results ha
ve been obtained\, in particular for the Ising model. Convergence results
have also been obtained for the near-critical dimer model\, which did not
allow to identify the limiting field\, even though it was conjectured to b
e the sine-Gordon field. I will present a derivation of the limit using di
screte massive holomorphy techniques\, which expresses the limiting field
as the solution of a certain Dirichlet problem associated with a massive D
irac operator. I will finally explain how to relate this field to the sine
-Gordon field. This is based on an ongoing work with Nathanaël Berestycki
and Scott Mason.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio Parra-Martinez (IHES)
DTSTART:20250128T123000Z
DTEND:20250128T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/95
DESCRIPTION:by Julio Parra-Martinez (IHES) as part of Seed Seminar of Math
ematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Pichon-Pharabod (Max Planck Institute for Mathematics in the
Sciences\, Leipzig)
DTSTART:20250128T140000Z
DTEND:20250128T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/96
DESCRIPTION:by Eric Pichon-Pharabod (Max Planck Institute for Mathematics
in the Sciences\, Leipzig) as part of Seed Seminar of Mathematics and Phys
ics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roberta Angius (University of Hamburg)
DTSTART:20250128T153000Z
DTEND:20250128T163000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/97
DESCRIPTION:by Roberta Angius (University of Hamburg) as part of Seed Semi
nar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/97/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefano De Angelis (IPhT)
DTSTART:20250204T093000Z
DTEND:20250204T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/98
DESCRIPTION:by Stefano De Angelis (IPhT) as part of Seed Seminar of Mathem
atics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sara Maggio (Department of Physics and Astronomy\, University of B
onn)
DTSTART:20250204T104500Z
DTEND:20250204T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/99
DESCRIPTION:by Sara Maggio (Department of Physics and Astronomy\, Universi
ty of Bonn) as part of Seed Seminar of Mathematics and Physics\n\nAbstract
: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/99/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Heissenberg (IPhT)
DTSTART:20250218T093000Z
DTEND:20250218T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/100
DESCRIPTION:by Carlo Heissenberg (IPhT) as part of Seed Seminar of Mathema
tics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Panzer (Mathematical Institute\, University of Oxford)
DTSTART:20250218T104500Z
DTEND:20250218T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/101
DESCRIPTION:by Erik Panzer (Mathematical Institute\, University of Oxford)
as part of Seed Seminar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mehregan Doroudiani (School of Physics and Astronomy\, University
of Southampton)
DTSTART:20250304T093000Z
DTEND:20250304T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/102
DESCRIPTION:by Mehregan Doroudiani (School of Physics and Astronomy\, Univ
ersity of Southampton) as part of Seed Seminar of Mathematics and Physics\
n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Pochart (CPhT\, École polytechnique)
DTSTART:20250304T104500Z
DTEND:20250304T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/103
DESCRIPTION:by Thomas Pochart (CPhT\, École polytechnique) as part of See
d Seminar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio Parra-Martinez (IHES)
DTSTART:20250128T123000Z
DTEND:20250128T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/104
DESCRIPTION:by Julio Parra-Martinez (IHES) as part of Seed Seminar of Math
ematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Pichon-Pharabod (Max Planck Institute for Mathematics in the
Sciences\, Leipzig)
DTSTART:20260128T140000Z
DTEND:20260128T150000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/105
DESCRIPTION:Title: Numerical computations of periods and monodromy representations\
nby Eric Pichon-Pharabod (Max Planck Institute for Mathematics in the Scie
nces\, Leipzig) as part of Seed Seminar of Mathematics and Physics\n\n\nAb
stract\nThe period matrix of a smooth complex projective variety encodes t
he isomorphism between its singular homology and its algebraic De Rham coh
omology. Numerical approximations with sufficient precision of the entries
of the period matrix allow to recover some algebraic invariants of the va
riety. Such approximations can be obtained from an effective description o
f the homology of the variety\, which itself can be obtained from the mono
dromy representation associated to a generic fibration. I will describe th
ese methods to several hundred digits\, and showcase implementations and a
pplications\, in particular to computation of the Picard rank of certain K
3 surfaces.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roberta Angius (University of Hamburg)
DTSTART:20260128T153000Z
DTEND:20260128T163000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/106
DESCRIPTION:Title: Thimble decomposition and Wall Crossing Structure for Physical Integ
rals\nby Roberta Angius (University of Hamburg) as part of Seed Semina
r of Mathematics and Physics\n\n\nAbstract\nA growing body of evidence sug
gests that the complexity of physical integrals is most naturally understo
od through geometry. Recent mathematical developments by Kontsevich and So
ibelman [arXiv:2402.07343] have illuminated the role of exponential integr
als as periods of twisted de Rham cocycles over Betti cycles\, offering a
structured approach to address this problem in a wide range of settings. I
n this talk\, I will first introduce the key tools underlying this structu
re and then apply them to show how families of physically relevant integra
ls\, ranging from holomorphic exponentials to logarithmic multivalued func
tions\, can be reformulated within this language. For holomorphic exponent
s\, I will present an explicit decomposition of a family of integrals into
thimbles expansion together with a detailed analysis of the wall-crossing
structure behind the analytic continuation of its relevant parameter. Fin
ally\, I will discuss the generalization to multivalued functions\, which
provides the appropriate framework for describing Feynman integrals in spe
cial representations.\nIn this context\, the thimble decomposition is expe
cted to match the decomposition into Master\nIntegrals\, while the study o
f the wall-crossing structure yields a precise count of independent Master
Integrals (or periods)\, circumventing complications arising from Stokes
phenomena\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefano De Angelis (IPhT)
DTSTART:20260304T083000Z
DTEND:20260304T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/107
DESCRIPTION:by Stefano De Angelis (IPhT) as part of Seed Seminar of Mathem
atics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sara Maggio (University of Bonn)
DTSTART:20260204T103000Z
DTEND:20260204T113000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/108
DESCRIPTION:Title: From polylogs to Calabi–Yau: canonical differential equations and
intersection theory\nby Sara Maggio (University of Bonn) as part of Se
ed Seminar of Mathematics and Physics\n\n\nAbstract\nFeynman integrals who
se associated geometries extend beyond the Riemann sphere\, such as ellipt
ic and Calabi–Yau geometries\, are becoming increasingly relevant in mod
ern precision calculations. They arise not only in collider cross-section
computations\, but also in gravitational-waves scattering.
A powerful approach to compute such integrals is based on systems of diff
erential equations\, in particular when these can be brought into a canoni
cal form\, in which their singularity structure is manifest. In this talk\
, I will show that canonical Feynman integrals do enjoy similar properties
\, albeit different associated geometries\, and I will illustrate how inte
rsection theory can be used to further study and constraint the functions
appearing in the amplitudes.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Heissenberg (IPhT)
DTSTART:20250218T093000Z
DTEND:20250218T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/109
DESCRIPTION:by Carlo Heissenberg (IPhT) as part of Seed Seminar of Mathema
tics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/109/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Panzer (University of Oxford)
DTSTART:20250218T104500Z
DTEND:20250218T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/110
DESCRIPTION:by Erik Panzer (University of Oxford) as part of Seed Seminar
of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mehregan Doroudiani (University of Southampton)
DTSTART:20260304T094500Z
DTEND:20260304T104500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/111
DESCRIPTION:Title: Scattering amplitude of closed strings at genus one\nby Mehregan
Doroudiani (University of Southampton) as part of Seed Seminar of Mathema
tics and Physics\n\n\nAbstract\nPerturbative calculations of string amplit
udes are twofold: an expansion in the string coupling (the genus expansion
of the worldsheet) and a low-energy expansion in the momenta. In this tal
k\, I will focus on the low-energy expansion of closed string amplitudes a
t genus one\, specifically for four- and five-point massless states of typ
e IIB superstrings in flat spacetime. Evaluating these amplitudes involves
integrating over the moduli space of punctured tori. I will demonstrate h
ow the formalism of equivariant iterated Eisenstein integrals can be used
to systematically calculate these integrals. Additionally\, I will discuss
the implications of these results for the S-duality of type IIB and concl
ude by exploring the underlying number-theoretic aspects of string amplitu
des.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Pochart (CPhT\, École polytechnique)
DTSTART:20260304T104500Z
DTEND:20260304T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/112
DESCRIPTION:Title: Ruelle scattering theory and the single-particle problem in the Wigh
tman framework\nby Thomas Pochart (CPhT\, École polytechnique) as par
t of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nIn this presen
tation\, I will first review what purposes axiomatic quantum field theory
serves and what the Wightman framework is and achieves. With that being \n
done\, I will address the question of the existence of the S-matrix in thi
s framework\, following a modern and dimension-independent approach to the
Haag--Ruelle scattering\; in doing so\, I will put a special emphasis on
the single-particle problem.\nWith all this discussion having taken place
in flat space\, I will conclude by presenting some ongoing work on an AdS
space version of these arguments.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/112/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Heissenberg (IPhT)
DTSTART:20250218T093000Z
DTEND:20250218T103000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/113
DESCRIPTION:by Carlo Heissenberg (IPhT) as part of Seed Seminar of Mathema
tics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Panzer (University of Oxford)
DTSTART:20250218T104500Z
DTEND:20250218T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/114
DESCRIPTION:by Erik Panzer (University of Oxford) as part of Seed Seminar
of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio Para-Martinez (IHES)
DTSTART:20260128T123000Z
DTEND:20260128T133000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/115
DESCRIPTION:Title: Feynman Periods in Classical and Quantum Field Theory\nby Julio
Para-Martinez (IHES) as part of Seed Seminar of Mathematics and Physics\n\
n\nAbstract\nIn this talk I will review the appearance of periods as Feynm
an integral associated to classical and quantum scattering.\nUsing some sp
ecific examples\, I will give a brief survey of the state of the art of th
e subject and describe in which physical quantities they arise.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Heissemberg (Institut de Physique Théorique)
DTSTART:20260218T083000Z
DTEND:20260218T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/116
DESCRIPTION:Title: Gravitational waveforms from differential equations\nby Carlo He
issemberg (Institut de Physique Théorique) as part of Seed Seminar of Mat
hematics and Physics\n\n\nAbstract\nThe direct detection of gravitational
waves has put the relativistic two-body problem in the spotlight and stimu
lated progress in perturbative approaches that provide analytic insight in
to its dynamics. Two strategies that have been witnessing interesting deve
lopments to this end are the ones based on scattering amplitudes\, which a
pply to binary scatterings at large impact parameter\, and on black-hole p
erturbation theory\, which applies to extreme-mass-ratio binaries. In this
talk\, I will discuss how two very different kinds of differential equati
ons have been playing a key role in such recent developments\, in particul
ar with the goal of characterizing the gravitational waves emitted and (re
)absorbed by these systems.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Panzer (Oxford University)
DTSTART:20260218T104500Z
DTEND:20260218T114500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/117
DESCRIPTION:Title: Tropical quantum field theory and asymptotics of perturbation theory
\nby Erik Panzer (Oxford University) as part of Seed Seminar of Mathem
atics and Physics\n\n\nAbstract\nTo compute properties of phase transition
s in condensed matter or the interactions of elementary particles\, quantu
m field theory is typically solved perturbatively. This expansion produces
divergent series\, so the extraction of meaningful results (resummation)
is not straightforward. In fact\, very little is known about the actual as
ymptotic behaviour of these series. In this talk\, I will introduce a new
limit of quantum field theory (the „tropical“ limit)\, which is easily
computable to very high orders in perturbation theory\, yet at the same t
ime captures the full complexity of subdivergences\, renormalization\, and
scheme dependence. I will illustrate that the values of Feynman integrals
and their tropical limit are highly correlated. Based on data up to 400 l
oops\, we can precisely determine the asymptotic growth of the (tropical)
beta function in different renormalization schemes. In particular\, we fin
d unexpectedly complicated instantons\, and we confirm the absence of reno
rmalons in the minimal subtraction scheme.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Blanchet (Institut de Mathématiques de Jussieu - Paris
Rive Gauche)
DTSTART:20260422T113000Z
DTEND:20260422T123000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/118
DESCRIPTION:Title: Introduction to non semi-simple TQFT\nby Christian Blanchet (Ins
titut de Mathématiques de Jussieu - Paris Rive Gauche) as part of Seed Se
minar of Mathematics and Physics\n\n\nAbstract\nA Topological Quantum Fiel
d Theory in dimension 2+1 assigns to a surface a vector \nspace (states)\,
together with an action of mapping classes and more generally \ncobordism
s. This includes invariants of 3-dimensional manifolds (correlation \nfunc
tions) possibly decorated with links or colored graphs. The starting point
was \nthe interpretation by Witten in the late 1980’ of the Jones polyn
omial invariant \nof knots in terms of Chern-Simons theory and the mathema
tical construction by \nReshetikhin-Turaev of the expected model\, now cal
led WRT theory.\nWRT is based on simple modules over the quantum group sl(
2) at root of unity\, \nwhich means that an important part of the represen
tation theory is neglected. \nStarting with a motivating example we will i
ntroduce to TQFTs which do use those \nneglectons. The non-simple TQFTs ha
ve two flavors. The graded version\, first \nconstructed by B-Costantino-G
eer-Patureau involves manifolds with cohomology class \n(or abelian flat c
onnection). The non graded version further developped by Marco \nde Renzi
and collaborators recovers Kerler-Lyubashenko representations of mapping \
nclass groups on tensor powers of the adjoint representation. We will desc
ribe the \nconstructions and the resulting TQFT spaces.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giovanni Rizi (IHES\, France)
DTSTART:20260422T130000Z
DTEND:20260422T140000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/119
DESCRIPTION:Title: TQFTs for physics\nby Giovanni Rizi (IHES\, France) as part of S
eed Seminar of Mathematics and Physics\n\n\nAbstract\nIn this talk I will
discuss some instances of how Topological Quantum Field Theories (TQFTs) a
ppear and are used in high-energy physics contexts. TQFTs describe gapped
phases of Quantum Field Theories (QFTs) and their relation with generalize
d symmetries makes them a useful classification tool for such phases. I wi
ll also highlight instances in which TQFT tools are useful beyond classifi
cation purposes and allow to describe more dynamical phenomena\, such as m
odified crossing in 1+1 dimensional scattering processes. Beyond describin
g gapped phases\, TQFTs are a useful method to describe the symmetry struc
ture of general QFTs via the Symmetry Topological Field Theory (SymTFT) co
nstruction. Time permitting I will also discuss some connections between T
QFTs with gravity and holographic dualities.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jules Martel (Université de Cergy-Pontoise)
DTSTART:20260422T143000Z
DTEND:20260422T153000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/120
DESCRIPTION:Title: Towards a homological reconstruction of TQFTs\nby Jules Martel (
Université de Cergy-Pontoise) as part of Seed Seminar of Mathematics and
Physics\n\n\nAbstract\nTQFTs are the idea of Witten that we can study quan
tum field theories from the \npoint of view of the topology of state space
s\nand of topological transitions. Mathematically\, it was formalised by A
tiyah as a \nlinearization of a cobordism category. It was concretely real
ized\nby Reshetikhin--Turaev (RT) coupled with Blanchet--Habbeger--Masbaum
--Vogel \nuniversal construction. The RT philosophy relies on a diagrammat
ic model\nfor cobordisms (based on knot diagrams) and uses modules on quan
tum groups (or \nmore generally monoidal categories) to model linearly the
se diagrams.\nThis has more recently been extended so to permit the utiliz
ation of non \nsemisimple monoidal categories as input of the construction
giving rise to a new \ngeneration of TQFTs\, for which\na nice example is
the Kerler--Lyubashenko (KL) construction.\nThese constructions need abst
ract algebra tools applied on diagrammatic \nrepresentations of manifolds\
, and we will try to avoid this by using homology \ntheories\,\nallowing a
more global definition of TQFTs.\n\nIn this talk I'll introduce a new phi
losophy to build TQFTs based on homology of \nconfiguration spaces. Repres
entations of mapping class groups constitute an \nimportant\nbyproduct of
TQFTs\, while more natural ones can be built out of twisted homologies \no
f configuration spaces of surfaces. We will show that from this latter new
\nframework we can recover\nstep by step the properties of KL TQFTs assoc
iated with quantum groups and even a \nunifying framework. I'll stay intro
ductory most of the talk but the constructions\nand their motivations will
be the occasion to review joint works with: S. Bigelow\, \nM. De Renzi\,
R. Detcherry or Q. Faes (depending on the time).\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sam Hindson (SDU\, Denmark)
DTSTART:20260429T083000Z
DTEND:20260429T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/121
DESCRIPTION:Title: WRT invariants as finite-dimensional integrals\nby Sam Hindson (
SDU\, Denmark) as part of Seed Seminar of Mathematics and Physics\n\n\nAbs
tract\nI will present ongoing joint work with J. E. Andersen and W. E. Mis
tegård on a general procedure for expressing WRT invariants of 3-manifold
s as finite-dimensional integrals. This technique is based on the universa
l R-matrix construction and features Faddeev's quantum dilogarithm in a ce
ntral way. Natural follow-up questions (in the direction of Witten's asymp
totic expansion conjecture) about the semiclassical behaviour of these int
egrals will then be touched upon\, which will involve a discussion of Yoon
's generalised potential function of a link diagram.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lea Bottini (IHES\, France)
DTSTART:20260429T094500Z
DTEND:20260429T104500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/122
DESCRIPTION:Title: Gapped phases and the SymTFT\nby Lea Bottini (IHES\, France) as
part of Seed Seminar of Mathematics and Physics\n\n\nAbstract\nThe symmetr
y topological field theory (SymTFT) has emerged in the past years as a pow
erful framework for analyzing generalized symmetries. In this talk\, I wil
l review how we can use it to characterize the gapped infrared phases of t
wo-dimensional quantum field theories with an internal symmetry\, describe
d in general by a fusion category. I will then discuss extensions of this
framework that incorporate space-time symmetries\, with a particular focus
on time-reversal.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:William Mistegård (SDU\, Denmark)
DTSTART:20260513T083000Z
DTEND:20260513T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/123
DESCRIPTION:by William Mistegård (SDU\, Denmark) as part of Seed Seminar
of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Haïoun (University of Edinburgh)
DTSTART:20260513T094500Z
DTEND:20260513T104500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/124
DESCRIPTION:Title: Graphical calculus for twisted pivotal categories\nby Benjamin H
aïoun (University of Edinburgh) as part of Seed Seminar of Mathematics an
d Physics\n\n\nAbstract\nGraphical calculus provides a convenient way to r
epresent objects and morphisms in a monoidal category using strands in the
plane. This viewpoint extends naturally to more general surfaces and lead
s to constructions of TQFTs\, such as the Turaev–Viro theories. In order
to obtain oriented TQFTs\, one usually uses a pivotal structure. In this
talk\, I will describe a more general approach based on a twisted pivotal
structure\, as predicted by the cobordism hypothesis. I will introduce a g
raphical calculus for these structures\, which involves foliated surfaces
and many drawings.\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maddalena Ferragatta (CPhT\, École polytechnique)
DTSTART:20260527T083000Z
DTEND:20260527T093000Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/125
DESCRIPTION:by Maddalena Ferragatta (CPhT\, École polytechnique) as part
of Seed Seminar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristina Anghel (LBMP\, Université Clermont Auvergne)
DTSTART:20260527T094500Z
DTEND:20260527T104500Z
DTSTAMP:20260422T225821Z
UID:SeedSeminar/126
DESCRIPTION:by Cristina Anghel (LBMP\, Université Clermont Auvergne) as p
art of Seed Seminar of Mathematics and Physics\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SeedSeminar/126/
END:VEVENT
END:VCALENDAR