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BEGIN:VEVENT
SUMMARY:Dmytro Volin (Nordita)
DTSTART:20200507T090000Z
DTEND:20200507T110000Z
DTSTAMP:20260404T111134Z
UID:LIJC/1
DESCRIPTION:Title: Completeness of Bethe equations\nby Dmytro Volin (Nordita) as part
of London Integrability Journal Club\n\n\nAbstract\nWe review a proof of
bijection between eigenstates of the Bethe algebra and solutions of Bethe
equations written as a Wronskian quantisation condition or as QQ-relations
on Young diagrams. Furthermore\, it is demonstrated that the Bethe algebr
a is maximal commutative and it has simple spectrum every time it is diago
nalisable. The proof covers rational gl(m|n) spin chains in the defining
representation with the famous Heisenberg spin chain being a particular su
bcase. The proof is rigorous (no general position arguments are used). We
do not rely on the string hypothesis and moreover we conjecture a precise
meaning of Bethe strings as a consequence of the proposed proof.\nA short
introduction with necessary facts about polynomial rings will be given at
the beginning of the talk. \nBased on 2004.02865\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shota Komatsu (IAS)
DTSTART:20200515T130000Z
DTEND:20200515T150000Z
DTSTAMP:20260404T111134Z
UID:LIJC/2
DESCRIPTION:Title: Wilson loops as matrix product states\nby Shota Komatsu (IAS) as p
art of London Integrability Journal Club\n\n\nAbstract\nIn his paper in 19
79\, Polyakov envisaged a possibility of reformulating the gauge theory as
a Principal Chiral Model defined on a space of loops and discussed "the l
oop-space integrability". This idea\, together with a closely related idea
of the loop equation\, led to numerous important results in matrix models
and 2d gauge theories\, but its application to four-dimensional gauge the
ories had only limited success. Now\, after 50 years\, we have a concrete
example of integrable four-dimensional gauge theory\, N=4 SYM. However int
egrability in N=4 SYM is formulated mostly in terms of local operators\, a
lthough important progress has been made in constructing the Yangian for t
he Wilson loops. In this talk\, I will present a framework which would bri
dge these two distant notions of integrabililty. The key player in the sto
ry is a correlation function of a local operator and the Wilson loop. I re
formulate the gauge-theory computation of this observable as an overlap be
tween an energy eigenstate of a spin chain and a matrix product state (MPS
). Unlike standard MPS's discussed in the literature\, our MPS has infinit
e bond dimensions in order to accommodate infinite dimensionality of the s
pace of loops. It provides an "intertwiner" between integrable structures
of the local operators and the Wilson loops\, and in particular implies th
e existence of a special set of deformations of the Wilson loop which sati
sfy the QQ-relation. I will also explain how to formulate a nonperturbativ
e bootstrap program based on the results obtained in this framework and co
mpute the correlator of the circular BPS Wilson loop and general non-BPS o
perators at finite coupling\, emphasizing the relation to and the differen
ce from other observables that were computed by a similar approach.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ines Aniceto (Southampton U)
DTSTART:20200521T130000Z
DTEND:20200521T150000Z
DTSTAMP:20260404T111134Z
UID:LIJC/3
DESCRIPTION:Title: Integrable Field Theories with an Interacting Massless Sector\nby
Ines Aniceto (Southampton U) as part of London Integrability Journal Club\
n\n\nAbstract\nIntegrability techniques have played a major role in the st
udy the AdS/CFT correspondence\, providing an accurate description of diff
erent string theoretic observables beyond the weak or strong coupling per
turbation theory. However\, the case of string on certain $AdS_3$ backgrou
nds provided new challenges in the form of massless excitations. Difficult
ies in incorporating these into the integrable description have led to dis
agreements concerning the energy of massive physical states. \nIn general
integrable theories\, massless and massive sectors can generally be treate
d separately. We know this cannot be the case in $AdS_3$\, but a full TBA
description of the interaction between the sectors is yet to be found. Sur
prisingly\, such a description can found in a family of integrable field t
heories — homogeneous sine-Gordon models. Here\, one can take a double
scaling limit of the adjustable parameters and zoom into a regime describe
d by a TBA where the massless sector does not decouple and contributes to
the energy of massive particles at the same order as for which the Bethe a
nsatz would suffice in a massive theory.\n\nannouncements also on https://
integrability-london.weebly.com/\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tamas Gombor (Wigner Research Centre for Physics)
DTSTART:20200528T130000Z
DTEND:20200528T150000Z
DTSTAMP:20260404T111134Z
UID:LIJC/4
DESCRIPTION:Title: Boundary states\, overlaps\, nesting and bootstrapping AdS/dCFT\nb
y Tamas Gombor (Wigner Research Centre for Physics) as part of London Inte
grability Journal Club\n\n\nAbstract\nRecently there have been renewed int
erest and relevant progress in calculating overlaps between periodic multi
particle states and integrable boundary states. They appear in quite disti
nct parts of theoretical physics including statistical physics and the ga
uge/string duality.\nI will give a summary of known overlap formulas and a
nalyze the connection between selection rules and symmetries. I will intro
duce a nesting procedure for boundary states which provides the factorizin
g overlaps for higher rank algebras automatically. This method can be used
for the calculation of the asymptotic all-loop 1-point functions in AdS/d
CFT. In doing so I will present the solutions of the YBE for the K-matrice
s with centrally extended su(2|2) symmetry and the generic overlaps of the
corresponding boundary states.\nBased on 2004.11329\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Olof Ohlsson Sax (Nordita)
DTSTART:20200604T140000Z
DTEND:20200604T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/5
DESCRIPTION:Title: Crossing equations for mixed flux AdS3/CFT2\nby Olof Ohlsson Sax (
Nordita) as part of London Integrability Journal Club\n\n\nAbstract\nI wil
l give an overview of recent progress in understanding string theory in Ad
S3 backgrounds with a mixture of\nRamond-Ramond and Neveu-Schwarz-Neveu-Sc
hwarz three-form flux. Such theories are integrable\, but provide many fea
tures\nnot encountered in the more familiar case of pure Ramond-Ramond flu
x. In this talk I will explore the analytic structure\nof the dispersion r
elation of the world-sheet excitations and how it relates to the crossing
equations of the\ntwo-particle S matrix. Determining the dressing phases o
f the mixed flux S matrix is the next major step in using\nintegrability t
o the AdS3/CFT2 correspondence.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gwenael Ferrando (Ecole Normale Superieure)
DTSTART:20200611T140000Z
DTEND:20200611T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/6
DESCRIPTION:Title: Fishnet CFT: TBA and Non-compact Spin Chain\nby Gwenael Ferrando (
Ecole Normale Superieure) as part of London Integrability Journal Club\n\n
\nAbstract\nThe fishnet CFT is a non-unitary CFT of two matrix complex sca
lar fields interacting via a single quartic potential. The chiral nature o
f the interaction strongly constrains the Feynman diagrams arising at each
order in perturbation theory\, those that survive are of fishnet type. In
this talk\, I will present the TBA equations for the conformal dimensions
of multi-magnon local operators in this theory. I will emphasize the need
to diagonalize suitable graph-building operators in order to determine th
e asymptotic data\, dispersion relation and S matrix\, on which the TBA re
lies. A dual version of the TBA equations\, relating D-dimensional graphs
to two-dimensional sigma models\, will also be examined. The last part of
the talk will be devoted to the presentation of the underlying non-compact
spin chain and of additional results regarding diagonalization of graph-b
uilding operators.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlo Meneghelli (Oxford)
DTSTART:20200723T140000Z
DTEND:20200723T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/7
DESCRIPTION:Title: Pre-fundamental representations for the Hubbard model and AdS/CFT\
nby Carlo Meneghelli (Oxford) as part of London Integrability Journal Club
\n\n\nAbstract\nThere is a class of representations of quantum groups\, re
ferred to as prefundamental representations\, that plays an important role
in the solution of integrable models. The first example of such represent
ations was given by V. Bazhanov\, S. Lukyanov and A. Zamolodchikov in the
context of two dimensional conformal field theory in order to construct Ba
xter Q-operators as transfer matrices. At the same time\, there is a rathe
r exceptional quantum group that governs the integrable structure of the o
ne dimensional Hubbard model and plays a fundamental role in the AdS/CFT c
orrespondence. In this talk I will introduce prefundamental representation
s for this quantum group\, explain their basic properties and discuss some
of their applications.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Caetano (YITP)
DTSTART:20200625T140000Z
DTEND:20200625T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/8
DESCRIPTION:Title: Exact g-functions\nby Joao Caetano (YITP) as part of London Integr
ability Journal Club\n\n\nAbstract\nThe g-function is a measure of degr
ees of freedom associated to a boundary of two-dimensional quantum field t
heories. In integrable theories\, it can be computed exactly in a form of
the Fredholm determinant\, but it is often hard to evaluate numerically. I
n this paper\, we derive functional equations---or equivalently integral e
quations of the thermodynamic Bethe ansatz (TBA) type---which directly com
pute the g-function in the simplest integrable theory\; the sinh-Gordon th
eory at the self-dual point. The derivation is based on the classic result
by Tracy and Widom on the relation between Fredholm determinants and TBA\
, which was used also in the context of topological string. As a side resu
lt\, we present multiple integrals of Q-functions which we conjecture to d
escribe a universal part of the g-function\, and discuss its implication t
o integrable spin chains.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marius de Leeuw
DTSTART:20200709T140000Z
DTEND:20200709T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/10
DESCRIPTION:Title: Solving the Yang-Baxter equation\nby Marius de Leeuw as part of
London Integrability Journal Club\n\n\nAbstract\nThe Yang-Baxter equation
is an important equation that appears in many\ndifferent areas of physics.
It signals the presence of integrable\nstructures which appear in topics
ranging from condensed matter physics\nto holography. In this talk I will
discuss a new method to find all\nregular solutions of the Yang-Baxter equ
ation by using the so-called\nboost automorphism. The main idea behind thi
s method is to use the\nHamiltonian rather than the R-matrix as a starting
point. I will\ndemonstrate our method by classifying all solutions of the
Yang-Baxter\nequation of eight-vertex type. I will also consider certain
9x9 and\n16x16 solutions and give new integrable models in all of these ca
ses. As\na further application\, I will discuss all integrable deformation
s of\nR-matrices that appear in the lower-dimensional cases of the AdS/CFT
\ncorrespondence.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergei Lukyanov
DTSTART:20200716T140000Z
DTEND:20200716T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/11
DESCRIPTION:Title: Density matrix for the 2D black hole from an integrable spin chain\nby Sergei Lukyanov as part of London Integrability Journal Club\n\n\nAb
stract\nTwenty years ago Maldacena\, Ooguri and Son constructed a modular
invariant partition function for the Euclidean black hole (cigar) NLSM. T
hey also proposed an expression for the corresponding density matrix.\nThi
s result played a key role in the formulation of the remarkable conjecture
by Ikhlef\, Jacobsen and Saleur that the Euclidean black hole NLSM underl
ies the critical behaviour of a certain integrable spin chain.\nIn this ta
lk we critically reexamine the above proposals.\n\nThe talk is based on th
e recent (unpublished) joint work with\nV. Bazhanov and G. Kotousov.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Davide Gaiotto (Perimeter)
DTSTART:20200917T140000Z
DTEND:20200917T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/12
DESCRIPTION:Title: 't Hooft operators and Q-functions\nby Davide Gaiotto (Perimeter)
as part of London Integrability Journal Club\n\n\nAbstract\nI will descri
be the role of 't Hooft operators in 4d Chern-Simons\ntheory and applicati
ons to integrability.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yifei He (IPhT\, Saclay)
DTSTART:20200924T140000Z
DTEND:20200924T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/13
DESCRIPTION:Title: Geometrical four-point functions in the 2d critical Q-state Potts mod
el\nby Yifei He (IPhT\, Saclay) as part of London Integrability Journa
l Club\n\n\nAbstract\nAn important example among the 2d geometrical critic
al phenomena is the critical Q-state Potts model\, which describes the per
colation in the limit Q-->1. In this talk I will consider the problem of d
etermining the geometrical four-point functions (cluster connectivities) i
n this model. Connections with the minimal models are made which uncover r
emarkable properties of the Potts amplitudes. Such properties allow to ded
uce the existence of "interchiral conformal blocks" which can be construct
ed using the degeneracy in the Potts spectrum. Using these\, I will then d
etermine the four-point functions through numerical bootstrap. In addition
\, I will also discuss the logarithmic nature of the Potts CFT and hints o
f a full analytic solution of the model.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pedro Vieira (Perimeter)
DTSTART:20201001T140000Z
DTEND:20201001T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/14
DESCRIPTION:Title: Multi-point Bootstrap and Integrability\nby Pedro Vieira (Perimet
er) as part of London Integrability Journal Club\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Florian Loebbert (Humboldt U)
DTSTART:20201008T141500Z
DTEND:20201008T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/15
DESCRIPTION:Title: Integrability for Feynman Integrals\nby Florian Loebbert (Humbold
t U) as part of London Integrability Journal Club\n\n\nAbstract\nIn this t
alk I give an overview of the Yangian symmetry of Feynman integrals. After
reviewing the connection between AdS/CFT integrability and the Yangian sy
mmetry of massless Feynman graphs\, I discuss the idea to bootstrap Feynma
n integrals based on the Yangian constraints. Then I show that also in the
massive case large classes of Feynman integrals are constrained by a Yang
ian extension of dual conformal symmetry. When translated to momentum spac
e\, this leads to a novel massive generalization of ordinary conformal sym
metry. Finally\, I argue that these features of massive Feynman integrals
can be understood as the integrability of planar scattering amplitudes in
a massive version of the so-called fishnet theory\, which is obtained as a
double-scaling limit of N=4 super Yang-Mills theory on the Coulomb branch
.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rouven Frassek (ENS)
DTSTART:20201015T141500Z
DTEND:20201015T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/16
DESCRIPTION:Title: QQ-system construction for so(2r) spin chains\nby Rouven Frassek
(ENS) as part of London Integrability Journal Club\n\n\nAbstract\nI will r
eview the QQ-system and oscillator construction of Q-operators for su(r+1)
spin chains and discuss its generalisation to so(2r) spin chains\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenz Eberhardt (IAS)
DTSTART:20201022T141500Z
DTEND:20201022T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/17
DESCRIPTION:Title: An exact AdS/CFT correspondence\nby Lorenz Eberhardt (IAS) as par
t of London Integrability Journal Club\n\n\nAbstract\nOne incarnation of t
he AdS/CFT correspondence is the duality between the symmetric product orb
ifold of T4 and superstrings on AdS3xS3xT4 with one unit of NS-NS flux. Co
mpared to other instances of AdS/CFT\, this duality is much simpler and ca
n in principle be fully understood. I will give a broad overview of the in
ner workings of the duality from a worldsheet CFT point of view\, physical
lessons and connections to integrability.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roberto Tateo (INFN\, Torino)
DTSTART:20201029T151500Z
DTEND:20201029T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/18
DESCRIPTION:Title: The TTbar deformation and a promising 4D generalisation\nby Rober
to Tateo (INFN\, Torino) as part of London Integrability Journal Club\n\n\
nAbstract\nTwo-dimensional field theories deformed by Zamolodchikov's TTba
r operator have recently attracted the attention of theoretical physicists
due to the many important links with string theory and AdS/CFT. In this t
alk\, I will describe various classical and quantum aspects of this partic
ular irrelevant perturbation\, including its geometrical interpretation at
the classical level.\n I will also introduce a generalisation of this g
eometrical framework to 4D field theories\, and discuss some of the intere
sting differences with the 2D case.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tristan McLoughlin (Trinity Coll.\, Dublin)
DTSTART:20201105T151500Z
DTEND:20201105T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/19
DESCRIPTION:Title: Non-planar N=4 SYM: from integrability to quantum chaos\nby Trist
an McLoughlin (Trinity Coll.\, Dublin) as part of London Integrability Jou
rnal Club\n\n\nAbstract\nIn this talk we will consider the spectrum of ano
malous dimensions in N=4 super-Yang-Mills and related theories. We will fi
rst discuss the emergence of quantum chaos as one goes from infinite to fi
nite N and how the perturbative spectrum is described by GOE random matrix
theory. We will then describe how the integrability of the planar-limit c
an be used to rewrite the computation of the leading 1/N corrections to th
e one-loop anomalous dimensions in terms of scalar products of off-shell B
ethe states or\, alternatively\, hexagon-like functions.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nicolai Reshetikhin (UC\, Berkeley)
DTSTART:20201112T151500Z
DTEND:20201112T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/20
DESCRIPTION:Title: Superintegrable systems on moduli spaces of flat connections\nby
Nicolai Reshetikhin (UC\, Berkeley) as part of London Integrability Journa
l Club\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jingxiang Wu (Perimeter)
DTSTART:20201119T151500Z
DTEND:20201119T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/21
DESCRIPTION:Title: Integrable Kondo line defect\, 4D Chern Simons\, and ODE/IM correspon
dence\nby Jingxiang Wu (Perimeter) as part of London Integrability Jou
rnal Club\n\n\nAbstract\nI will discuss the integrability and wall-crossin
g properties of Kondo line defects in rational conformal field theories. I
t provides a large class of interesting defect RG flow starting from topol
ogical line defects. As a surprise\, I will discuss new examples of the OD
E/IM correspondence and our attempts towards its physical origin using 4d
Chern Simons theory. This work is part of a multi-pronged exploration of s
tudying 4D Chern-Simons theory as an overarching structure for integrable
systems.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorge Russo (ICREA\, Barcelona)
DTSTART:20201203T151500Z
DTEND:20201203T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/22
DESCRIPTION:Title: Phases of unitary matrix models and lattice QCD in two dimensions
\nby Jorge Russo (ICREA\, Barcelona) as part of London Integrability Journ
al Club\n\n\nAbstract\nWe investigate the different large N phases of a de
formed Gross-Witten-Wadia U(N) matrix model. The deformation\, which leads
to a solvable model\, corresponds to the addition of characteristic polyn
omial insertions and mimics the one-loop determinant of fermion matter. In
one version of the model\, the GWW phase transition is smoothed out and i
t becomes a crossover. In another version\, the phase transition occurs al
ong a critical line in the two-dimensional parameter space spanned by the
't~Hooft coupling $\\lambda $ and the Veneziano parameter $\\tau $. A calc
ulation of the $\\beta $ function shows the existence of an IR stable fixe
d point.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthias Wilhelm (Niels Bohr Institutet)
DTSTART:20201210T151500Z
DTEND:20201210T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/23
DESCRIPTION:Title: An Operator Product Expansion for Form Factors\nby Matthias Wilhe
lm (Niels Bohr Institutet) as part of London Integrability Journal Club\n\
n\nAbstract\nIn this talk\, I discuss an operator product expansion for pl
anar form factors of local operators in N=4 SYM theory. In this expansion\
, a form factor is decomposed into a sequence of known pentagon transition
s and a new universal object - the form factor transition. This transition
is subject to a set of non-trivial bootstrap constraints\, which can be u
sed to determine it at finite coupling. I demonstrate this for MHV form fa
ctors of the chiral half of the stress tensor supermultiplet\, which in pa
rticular contains the chiral Lagrangian and the 20'.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:LIJC Gong Show
DTSTART:20201126T151500Z
DTEND:20201126T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/24
DESCRIPTION:Title: LIJC Gong Show\nby LIJC Gong Show as part of London Integrability
Journal Club\n\n\nAbstract\n\\( \\)\n\nStefano Baiguera "Non-relativistic
near-BPS corners of N=4 super Yang-Mills with SU(1\,1) symmetry"\n\nIlija
Buric "From Integrable Gaudin Models to Multipoint Conformal Blocks"\n\nJ
ulius Julius "Baxter Equation for Boundary Integrability"\n\nRob Klabbers
"How coordinate Bethe ansatz works for Inozemtsev model"\n\nYuan Miao "On
the Q-operator and the spectrum of the XXZ model at root of unity"\n\nAnne
Spiering "Integrability and Quantum Chaos in N=4 SYM from the Spectral Ri
gidity"\n\nAbstracts can be found on https://integrability-london.weebly.c
om/gong-show.html\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:LIJC Gong Show
DTSTART:20201217T151500Z
DTEND:20201217T173500Z
DTSTAMP:20260404T111134Z
UID:LIJC/25
DESCRIPTION:Title: LIJC Gong Show\nby LIJC Gong Show as part of London Integrability
Journal Club\n\n\nAbstract\nSara Bonansea "Wilson loop correlators in def
ect N=4 SYM"\n\nAndrea Fontanella "Lie Algebra Expansion in Coset Sigma Mo
dels and Non-relativistic String Theory"\n\nSuvajit Majumder "Protected st
ates in AdS3xS3xT4 from integrability"\n\nGerben Oling "Non-relativistic s
trings and limits of AdS/CFT"\n\nChiara Paletta "Integrable open quantum s
ystems"\n\nDavide Polvara "From tree-level perturbation theory to the S-ma
trix bootstrap in two dimensions"\n\nAnton Pribytok "Deformed AdS Integrab
ility and Free Fermion Condition"\n\nAbstracts can be found on https://int
egrability-london.weebly.com/gong-show.html\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul Fendley (Oxford U.)
DTSTART:20210114T151500Z
DTEND:20210114T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/26
DESCRIPTION:Title: Integrability and Braided Tensor Categories\nby Paul Fendley (Oxf
ord U.) as part of London Integrability Journal Club\n\n\nAbstract\nMany i
ntegrable critical classical statistical mechanical models and the corresp
onding quantum spin chains possess a fractional-spin conserved current. Th
ese currents have been constructed by utilising quantum-group algebras\, f
ermionic and parafermionic operators\, and ideas from ``discrete holomorph
icity''. I define them generally and naturally using a braided tensor cate
gory\, a topological structure familiar from the study of knot invariants\
, anyons and conformal field theory. Such a current amounts to terminating
a lattice topological defect\, and I will touch on related work on such d
one with Aasen and Mong. I show how requiring a current be conserved yield
s simple constraints on the Boltzmann weights\, and that all of the many m
odels known to satisfy these constraints are integrable. This procedure th
erefore gives a linear construction for ``Baxterising''\, i.e. building a
solution of the Yang-Baxter equation out of topological data.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Charlotte Kristjansen (Niels Bohr Institute)
DTSTART:20210121T151500Z
DTEND:20210121T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/27
DESCRIPTION:Title: Overlaps and Fermionic Dualities for Integrable Super Spin Chains
\nby Charlotte Kristjansen (Niels Bohr Institute) as part of London Integr
ability Journal Club\n\n\nAbstract\nThe $\\mathfrak{psu}(2\,2|4)$ integrab
le super spin chain underlying the AdS/CFT correspondence has integrable b
oundary states which describe set-ups where $k$ D3-branes get dissolved in
a probe D5-brane. Overlaps between Bethe eigenstates and these boundary s
tates encode the one-point functions of conformal operators and are expres
sed in terms of the superdeterminant of the Gaudin matrix that in turn dep
ends on the Dynkin diagram of the symmetry algebra. The different possible
Dynkin diagrams of super Lie algebras are related via fermionic dualities
and we determine how overlap formulae transform under these dualities. As
an application we show how to consistently move between overlap formulae
obtained for $k=1$ from different Dynkin diagrams.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gustavo Joaquin Turiaci (UC\, Santa Barbara)
DTSTART:20210128T151500Z
DTEND:20210128T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/28
DESCRIPTION:Title: 2D dilaton-gravity\, matrix models\, and the minimal string\nby G
ustavo Joaquin Turiaci (UC\, Santa Barbara) as part of London Integrabilit
y Journal Club\n\n\nAbstract\nIn the first part of this talk I will review
the recent realization that a large class of two-dimensional theories of
dilaton-gravity in asymptotically AdS space are holographically dual to a
random matrix model. In this description the matrix represents a random bo
undary Hamiltonian\, and its probability distribution depends on the dilat
on potential in a specific way. In the second part of the talk I will expl
ain the relation between two-dimensional dilaton-gravity and the minimal s
tring theory.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junya Yagi (Perimeter)
DTSTART:20210204T151500Z
DTEND:20210204T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/29
DESCRIPTION:Title: Wilson-'t Hooft lines as transfer matrices\nby Junya Yagi (Perime
ter) as part of London Integrability Journal Club\n\n\nAbstract\nSupersymm
etric gauge theories in four dimensions have various interrelated connecti
ons to quantum integrable systems. I will present a new correspondence whi
ch identifies Wilson-'t Hooft lines in N=2 circular quiver theories with t
ransfer matrices of trigonometric systems. I will explain how this corresp
ondence is related to Costello's 4d Chern-Simons theory and other similar
correspondences. This is based on my joint work with Kazunobu Maruyoshi an
d Toshihiro Ota.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oleksandr Gamayun (Amsterdam U.)
DTSTART:20210211T151500Z
DTEND:20210211T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/30
DESCRIPTION:Title: Modeling finite-entropy states with free fermions\nby Oleksandr G
amayun (Amsterdam U.) as part of London Integrability Journal Club\n\n\nAb
stract\nThe behavior of dynamical correlation functions in one-dimensional
quantum systems at zero temperature is now very well understood in terms
of linear and non-linear Luttinger models. The "microscopic" justification
of these models consists in exactly accounting for the soft-mode excitati
ons around the vacuum state and at most a few high-energy excitations. At
finite temperature\, or more generically for finite entropy states\, this
direct approach is not strictly applicable due to the different structure
of soft excitations. To address these issues we study the asymptotic behav
ior of correlation functions in one-dimensional free fermion models. On th
e one hand\, we obtain exact answers in terms of Fredholm determinants. On
the other hand\, based on "microscopic" numerical resummations\, we devel
op a phenomenological approach that provides results depending only on the
state-dependent dressing of the scattering phase. Our main example will b
e the sine-kernel and correlation functions in XY model.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Volker Schomerus (DESY)
DTSTART:20210218T151500Z
DTEND:20210218T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/31
DESCRIPTION:Title: Conformal Fourier Analysis and Gaudin Integrability\nby Volker Sc
homerus (DESY) as part of London Integrability Journal Club\n\n\nAbstract\
nConformal partial wave expansion provide Fourier-like decompositions of c
orrelation functions in Conformal Field Theory. Despite their fundamental
importance\, conformal partial waves remain poorly understood\, at least b
eyond the case of four local fields. In the last few years\, a deep relati
on with integrable quantum mechanical models has emerged. It offers a weal
th of powerful new algebraic methods to study and construct conformal part
ial waves e.g. for general supermultiplets\, non-local (line-\, surface-)
operators and multi-point correlation functions. In my talk I will use ide
as from harmonic analysis of the conformal group to embed conformal partia
l waves into the framework of Gaudin integrable models and then discuss se
veral concrete ramifications as trigonometric and elliptic Calogero-Suther
land models. The latter are relevant for multi-point blocks of scalar fiel
ds.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benoit Vicedo
DTSTART:20210225T151500Z
DTEND:20210225T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/32
DESCRIPTION:Title: Integrable E-models\, 4d Chern-Simons theory and affine Gaudin models
\nby Benoit Vicedo as part of London Integrability Journal Club\n\n\nA
bstract\nTwo-dimensional integrable field theories are characterised by th
e existence of infinitely many integrals of motion. Recently\, two unifyin
g frameworks for describing such theories have emerged\, based on four-dim
ensional Chern-Simons theory in the presence of surface defects and on Gau
din models associated with affine Kac-Moody algebras. I will explain how t
hese formalisms can be used to construct infinite families of two-dimensio
nal integrable field theories. The latter can all naturally be formulated
as so-called E-models\, a framework for describing Poisson-Lie T-duality i
n sigma-models. The talk will be based on the joint work [arXiv:2008.01829
] with M. Benini and A. Schenkel and [2011.13809] with S. Lacroix.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Coronado (McGill U.)
DTSTART:20210304T151500Z
DTEND:20210304T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/33
DESCRIPTION:Title: Ten dimensional hidden symmetry of N=4 SYM\nby Frank Coronado (Mc
Gill U.) as part of London Integrability Journal Club\n\n\nAbstract\nI wil
l present a generating function for the loop-integrands of all four-point
functions of protected single-trace operators in N=4 super Yang-Mills. Thi
s function enjoys a ten-dimensional symmetry that combines spacetime and t
he internal R-charge symmetries. By considering a 10D light-like limit I w
ill establish a relationship between the simplest four-point correlators (
octagons) and four-particle amplitudes.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikita Nekrasov (Stony Brook U.\, New York\, SCGP)
DTSTART:20210311T151500Z
DTEND:20210311T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/34
DESCRIPTION:Title: Lefschetz thimbles in sigma models\nby Nikita Nekrasov (Stony Bro
ok U.\, New York\, SCGP) as part of London Integrability Journal Club\n\n\
nAbstract\nTwo dimensional sigma models describe (harmonic) maps of Rieman
n surfaces to Riemannian manifolds. I will present the motivations to stud
y the complexification of this problem. I will present the novel approach\
, developed in my work with Igor Krichever\, allowing to construct essenti
ally all twisted complexified harmonic maps of two-torus to spheres and pr
ojective spaces.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takato Yoshimura (Tokyo Inst. Tech.)
DTSTART:20210318T110000Z
DTEND:20210318T130000Z
DTSTAMP:20260404T111134Z
UID:LIJC/35
DESCRIPTION:Title: TTbar-deformed conformal field theories out of equilibrium\nby Ta
kato Yoshimura (Tokyo Inst. Tech.) as part of London Integrability Journal
Club\n\n\nAbstract\nIn this talk I will discuss the universal properties
of transport phenomena in TTbar-deformed conformal field theories. TTbar-d
eformed CFTs are exactly solvable and admit a number of approaches\, each
of which is seemingly unrelated. Amongst them\, for our purpose\, which is
to study transport phenomena in TTbar-deformed CFTs\, we make use of the
following: integrability and holography. I will apply these two approaches
to study non-equilibrium steady states and Drude weights\, finding perfec
t agreement. I will also discuss a curious connection between TTbar-deform
ed CFTs and an integrable cellular automaton model called the Rule 54 chai
n.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Igor Klebanov (Princeton U.)
DTSTART:20210325T151500Z
DTEND:20210325T170000Z
DTSTAMP:20260404T111134Z
UID:LIJC/36
DESCRIPTION:Title: Confining or Not?\nby Igor Klebanov (Princeton U.) as part of Lon
don Integrability Journal Club\n\n\nAbstract\nThe problem of Color Confine
ment in Yang-Mills theory is one of the deepest problems in theoretical ph
ysics. There is convincing numerical evidence from Lattice Gauge Theory\,
yet the proof of Confinement in Asymptotically Free theories has not been
found. I will briefly introduce the Confinement problem and review some re
sults on large N theories using the gauge/gravity duality. I will then dis
cuss two-dimensional SU(N) theory coupled to an adjoint Majorana fermion.
I will show that\, when the adjoint mass is sent to zero\, the spectrum re
tains a mass gap but the confinement disappears. Using the Discretized Lig
ht-Cone Quantization\, I will discuss the spectrum of color singlet states
and exhibit certain threshold states. Similar threshold states are also p
resent in a model with a massless adjoint and a massive fundamental fermio
n. They provide new evidence for the lack of confinement. When the adjoint
mass is turned on\, the theory becomes confining\, and the spectrum of bo
und states becomes discrete.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sylvain Lacroix
DTSTART:20210401T141500Z
DTEND:20210401T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/37
DESCRIPTION:Title: Affine Gaudin models and integrable sigma-models\nby Sylvain Lacr
oix as part of London Integrability Journal Club\n\n\nAbstract\nIn this ta
lk\, I will discuss how the formalism of affine Gaudin models can be used
to construct new integrable sigma-models. I will start by reviewing the co
nstruction of affine Gaudin models and their interpretation as integrable
two-dimensional field theories. I will then explain how well-chosen realis
ations of these models give integrable coupled sigma model on an arbitrary
number of copies of a Lie group G^N as well as integrable coset models on
the quotient of G^N by a diagonal subgroup. In particular\, I will discus
s application of the latter construction to T^11 manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vladimir Korepin (SUNY\, Stony Brook)
DTSTART:20210422T141500Z
DTEND:20210422T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/38
DESCRIPTION:Title: Lattice nonlinear Schroedinger equation: history and open problems\nby Vladimir Korepin (SUNY\, Stony Brook) as part of London Integrabilit
y Journal Club\n\n\nAbstract\nThe model has many names: Lieb-Liniger\, Bos
e gas with delta interaction and nonlinear Schoedinger. A limiting case is
called Tonks-Girardeau. It is solvable by algebraic Bethe ansatz. We shal
l use notations of quantum inverse scattering method. Applications will be
mentioned.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Basso
DTSTART:20210429T141500Z
DTEND:20210429T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/39
DESCRIPTION:Title: Scattering Amplitudes Near the Origins: Localization and Globalizatio
n\nby Benjamin Basso as part of London Integrability Journal Club\n\n\
nAbstract\nI will talk about the behaviour of gluon scattering amplitudes
in planar N=4 SYM near kinematical corners coined Origins where maximally-
helicity-violating amplitudes are expected to be exactly Gaussian in the l
ogs of the cross ratios and exactly predictable. In part 1\, I will recall
how much is known about this behaviour for the 6-gluon amplitude and inte
rpret the result as a sort of quantum area convoluting the minimal surface
TBA data with an effective coupling constant\, known as the tilted cusp a
nomalous dimension. In part 2\, I will present a generalization to any num
ber of gluons and explore (some bit of) the emerging parterre of Origins.
If time permits\, I will discuss applications to scattering amplitudes in
the null limit where all two-particle Mandelstam vanish simultaneously. Th
e talk is based on a work in progress with Lance Dixon\, Yu-Ting Liu and G
eorgios Papathanasiou.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yunfeng Jiang (Southeast U.\, Nanjing)
DTSTART:20210513T141500Z
DTEND:20210513T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/41
DESCRIPTION:Title: OPE coefficients in ABJM theory with giants\nby Yunfeng Jiang (So
utheast U.\, Nanjing) as part of London Integrability Journal Club\n\n\nAb
stract\nIn this talk\, I will discuss a family of three-point functions in
ABJM theory\, both at weak and strong coupling. This family of three-poin
t functions involve two BPS sub-determinant operators called giant gravito
ns and one single trace operator\, which can be BPS or non-BPS. In the fir
st part of the talk\, I will explain how to compute this type of three-poi
nt function at weak coupling using a large N effective field theory. The s
tructure constant is given by the overlap of an integrable matrix product
state and a Bethe state. In the second part\, I will first clarify the pre
scription of computation at strong coupling. I will show that it is import
ant to perform an average over the moduli space and also take into account
the contributions from wave functions. The prescription is tested in N=4
SYM theory and then applied to ABJM theory.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Congkao Wen (QMUL)
DTSTART:20210520T141500Z
DTEND:20210520T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/42
DESCRIPTION:Title: Integrated four-point correlators in N=4 super Yang-Mills\nby Con
gkao Wen (QMUL) as part of London Integrability Journal Club\n\n\nAbstract
\nWe will study the correlation function of four superconformal primaries
in N=4 super Yang-Mills (SYM) with SU(N) gauge group. Recently\, very powe
rful methods have been developed to compute this correlator at finite coup
ling based on a new concept of integrated correlators\, which are defined
by integrating the correlator over spacetime coordinates with suitable int
egration measures. The integrated correlators can be computed using supers
ymmetric localisation. We will mostly focus on one of the integrated corre
lators. An exact expression was found for this integrated correlator for a
rbitrary values of coupling and N. The integrated correlator can be expres
sed as a two-dimensional lattice sum\, which manifests the SL(2\, Z) modul
ar invariance of N=4 SYM. Furthermore\, the result obeys an elegant Laplac
e-difference equation that relates the correlator of SU(N) theory with tho
se of SU(N-1) and SU(N+1) theories. In perturbation\, the formula is check
ed to be consistent with known results from more standard methods. Finally
\, one can reconstruct the unintegrated correlator with finite coupling fo
r first few orders in large-N expansion\, the results are shown to agree w
ith known type IIB superstring amplitudes due to AdS/CFT duality. This tal
k will be mainly based on https://arxiv.org/abs/2102.09537 (a short versio
n can be found at https://arxiv.org/abs/2102.08305).\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Balazs Pozsgay (Eotvos U.)
DTSTART:20210506T141500Z
DTEND:20210506T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/43
DESCRIPTION:Title: Current operators in integrable models (a review)\nby Balazs Pozs
gay (Eotvos U.) as part of London Integrability Journal Club\n\n\nAbstract
\nCurrent operators describe the flow of the conserved charges in integrab
le models. Whereas lots of information was known about the charges\, surpr
isingly the current operators remained unexplored for a very long time. I
review recent results in this topic\, which include an exact finite volume
formula for the mean values of the current operators\, their embedding in
to the Quantum Inverse Scattering Approach (Algebraic Bethe Ansatz)\, and
connections with long range deformations and TTbar deformations.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gong Show
DTSTART:20210527T141500Z
DTEND:20210527T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/44
DESCRIPTION:Title: LIJC Gong Show\nby Gong Show as part of London Integrability Jour
nal Club\n\n\nAbstract\nSchedule:\n\n15.15-15.30 \, Nat Levine\, "Embeddin
g integrable sigma models in string theory"\n\n15.30-15.45\, Juan Miguel
Nieto Garcia\, "Three-parameter deformation of R×S3 in the Landau-Lifshit
z limit"\n\n15.45-16.00\, Tomas Reis\, "Renormalons from Resurgence"\n\n16
.00-16.15\, Coffe-break\n\n16.15-16.30\, Gabriel Bliard\, "Mellin amplitud
es for 1D CFT" \n\n16.30-16.45\, Fabrizio Del Monte\, "BPS quivers of five
-dimensional SCFTs\, Topological Strings and q-Painlevé equations"\n\n16.
45-17.00\, Leonardo Santilli\, "TTbar deformation of q-Yang-Mills theory"\
n
LOCATION:https://stable.researchseminars.org/talk/LIJC/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony (Weizmann Inst.)
DTSTART:20210603T141500Z
DTEND:20210603T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/45
DESCRIPTION:Title: A gravity interpretation for the Bethe ansatz expansion of the N=4 SY
M superconformal index\nby Ofer Aharony (Weizmann Inst.) as part of Lo
ndon Integrability Journal Club\n\n\nAbstract\nThis (blackboard) talk is b
ased on 2104.13932 and on work in progress with Francesco Benini\, Ohad Ma
mroud and Paolo Milan. I will begin by briefly reviewing the superconforma
l index of the d=4 N=4 SU(N) supersymmetric Yang-Mills theory\, how it is
related (in the large N limit) to counting black hole microstates\, and ho
w it can be computed. I will then review a specific way to compute the ind
ex called the Bethe ansatz expansion\, and describe the known solutions to
the Bethe ansatz equations\, and what they contribute to the index in the
large N limit\, including both perturbative and non-perturbative terms in
1/N. The index is related to the partition function of N=4 SYM on S^3xS^1
\, and in the large N limit this should be related by the AdS/CFT correspo
ndence to a sum over Euclidean gravity solutions with appropriate asymptot
ic behavior. I will show that each known Bethe ansatz contribution arises
from a specific supersymmetric (complex) black hole solution\, which repro
duces both its perturbative and its non-perturbative behavior (the latter
comes from wrapped Euclidean D3-branes). A priori there are many more grav
itational solutions than Bethe ansatz contributions\, but we show that by
considering the non-perturbative effects\, the extra solutions are ruled o
ut\, leading to a precise match between the solutions on both sides.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vladimir Kazakov (ENS Paris)
DTSTART:20210610T141500Z
DTEND:20210610T160000Z
DTSTAMP:20260404T111134Z
UID:LIJC/46
DESCRIPTION:Title: Dually weighted graphs and 2d quantum gravity\nby Vladimir Kazako
v (ENS Paris) as part of London Integrability Journal Club\n\n\nAbstract\n
Dually weighted graphs (DWG) are planar Feynman graphs bearing two sets
of couplings: one set of usual couplings $t_n$ attached to the vertices o
f valence $n$\, and another set of dual couplings $t_n^*$ attached to th
e faces (dual vertices) of valence $n$. Such couplings allow a deep con
trol on possible shapes of planar graphs. For example\, if one turns on on
ly the couplings $t_4$ and $t_4^*$ the graph takes a "fishnet form" of
a regular square lattice. The problem of counting of such graphs can be f
ormulated as a modified hermitian one matrix model with an extra constant
matrix. The partition function can be then represented in terms of the "ch
aracter expansion" over Young tableaux\, solvable by the saddle point app
roximation. I will review old results on DWG from my papers with M.Stau
dacher and Th.Wynter\, including the techniques of computing Schur charac
ters of a large Young tableau and deriving the elliptic algebraic curve f
or counting of planar quadrangulations. Then I will present new results f
rom our ongoing work with F.Levkovich-Maslyuk where we count the disc qu
adrangulations with large\, macroscopic area and boundary. This allows to
extract interesting continuous limit of fluctuating 2d geometry\, interp
olating between the "almost" flat disc with a few dynamical conical defect
s and the disc partition function for pure 2d quantum gravity\, generaliz
ing old results for the spherical topology.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:LIJC Gong Show
DTSTART:20210617T134500Z
DTEND:20210617T150000Z
DTSTAMP:20260404T111134Z
UID:LIJC/47
DESCRIPTION:by LIJC Gong Show as part of London Integrability Journal Club
\n\n\nAbstract\nSchedule:\n\n14.45 - 15.00\, Ilija Buric\, "Defect conform
al blocks from the Iwasawa decomposition"\n\n15.00 - 15.15\, Daniele Grego
ri\, "Integrability and cycles of deformed N=2 gauge theory"\n\n15.15 - 15
.30\, Luigi Guerrini\, "A duality for the latitude Wilson loop in ABJM"\n\
n15.30 - 15.45\, Enrico Olivucci\, "Hexagons in Fishnet theories: direct d
erivation"\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zohar Komargodski (Stony Brook U.\, New York\, SCGP)
DTSTART:20211007T144500Z
DTEND:20211007T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/48
DESCRIPTION:Title: Renormalization Group Flows on Line Defects\nby Zohar Komargodski
(Stony Brook U.\, New York\, SCGP) as part of London Integrability Journa
l Club\n\n\nAbstract\nWe will review the subject of line defects in d-dime
nsional Conformal Field Theories (CFTs). We discuss an exact formula gover
ning the renormalization group flow on line defects and consider some exam
ples involving line defects in 2\,3\, and 4 space-time dimensions.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elli Pomoni (DESY)
DTSTART:20211014T144500Z
DTEND:20211014T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/49
DESCRIPTION:Title: Dynamical spin chains in 4D N = 2 SCFTs\nby Elli Pomoni (DESY) as
part of London Integrability Journal Club\n\n\nAbstract\nIn this talk we
will revisit the study of spin chains capturing the spectral problem of 4d
N = 2 SCFTs in the planar limit. At one loop and in the quantum plane lim
it\, we will discover a quasi-Hopf symmetry algebra\, defined by the R-mat
rix read off from the superpotential. This implies that when orbifolding t
he N = 4 symmetry algebra down to the N = 2 one and then marginaly deformi
ng\, the broken generators are not lost\, but get upgraded to quantum gene
rators. We will also demonstrate that these chains are dynamical\, in the
sense that their Hamiltonian depends on a parameter which is dynamically d
etermined along the chain. At one loop we will show how to map the holomor
phic SU(3) scalar sector to a dynamical 15-vertex model\, which correspond
s to an RSOS model\, whose adjacency graph can be read off from the gauge
theory quiver/brane tiling. One scalar SU(2) sub-sector is described by an
alternating nearest-neighbour Hamiltonian\, while another choice of SU(2)
sub-sector leads to a dynamical dilute Temperley-Lieb model. These sector
s have a common vacuum state\, around which the magnon dispersion relation
s are naturally uniformised by elliptic functions. For the example of the
ℤ_{2} quiver theory we study these dynamical chains by solving the one-
and two-magnon problems with the coordinate Bethe ansatz approach.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zechuan Zheng (ENS Paris)
DTSTART:20211021T144500Z
DTEND:20211021T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/50
DESCRIPTION:Title: Matrix bootstrap revisited\nby Zechuan Zheng (ENS Paris) as part
of London Integrability Journal Club\n\n\nAbstract\nMatrix bootstrap is a
new method for the numerical study of (multi)-matrix models in the planar
limit\, using loop equations for moments of distribution (Ward identities
and factorization of traces at infinite N). The lack of information associ
ated with the use of only a finite number of lower moments is supplemented
by the conditions of positivity of the correlation matrix. The numerical
solution of loop equations and these conditions leads to inequalities for
the lowest moments\, which rapidly converge to exact values with an
increase in the number of used moments. In our work https://arxiv.org/pdf/
2108.04830.pdf\, the method was tested on the example of the standard one-
matrix model\, as well as on the case of an “unsolvable” 2-matrix mode
l with the interaction $tr[A\, B]^2$ and with quartic potentials. We propo
se a significant improvement of original H.Lin’s proposal for matrix boo
tstrap by introducing the relaxation procedure: we replace the non-convex\
, non-linear loop equations by convex inequalities. The results look quite
convincing and matrix bootstrap seems to be an interesting alternative to
the Monte Carlo method. For example\, for $\\langle tr A^2 \\rangle$\, th
e precision reaches 6 digits (with modest computer resources). I will disc
uss the prospects for applying the method in other\, physically interestin
g systems.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simeon Hellerman (Tokyo U.\, IPMU)
DTSTART:20211104T100000Z
DTEND:20211104T120000Z
DTSTAMP:20260404T111134Z
UID:LIJC/51
DESCRIPTION:Title: Precision Correlators at Large R-Charge\nby Simeon Hellerman (Tok
yo U.\, IPMU) as part of London Integrability Journal Club\n\nAbstract: TB
A\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jake Stedman
DTSTART:20211111T154500Z
DTEND:20211111T173000Z
DTSTAMP:20260404T111134Z
UID:LIJC/52
DESCRIPTION:Title: Gauged sigma models from four-dimensional Chern-Simons\nby Jake S
tedman as part of London Integrability Journal Club\n\n\nAbstract\nSeveral
years ago\, a new gauge theory called four-dimensional Chern-Simons was i
ntroduced by Costello in an attempt to explain the integrability of variou
s two-dimensional models using techniques in gauge theory. My work focuses
on the use of four-dimensional Chern-Simons to explain the integrability
of two-dimensional sigma models. I will begin by reviewing the constructio
n of the Wess-Zumino-Witten (WZW) model as the boundary theory of three-di
mensional Chern-Simons theory as was introduced by Moore and Seiberg. This
will allow me to introduce the analogous construction of Costello and Yam
azaki\, in which two-dimensional sigma models appear as theories on defect
s in four-dimensional Chern-Simons. This naturally leads to a discussion o
f my work in which I construct a large class of gauged sigma models by cou
pling together two four-dimensional Chern-Simons theories. I will argue th
at the structure of four-dimensional Chern-Simons suggests that these mode
ls are integrable and finish by constructing the gauged WZW model and conf
ormal Toda theories. This talk is based on: https://arxiv.org/abs/2109.081
01.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mykola Dedushenko (SUNY\, Stony Brook)
DTSTART:20211028T144500Z
DTEND:20211028T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/53
DESCRIPTION:Title: Quantum algebras and SUSY interfaces in Bethe/gauge correspondence\nby Mykola Dedushenko (SUNY\, Stony Brook) as part of London Integrabili
ty Journal Club\n\n\nAbstract\nI will describe my work with N.Nekrasov on
supersymmetric interfaces in gauge theories in the context of the Bethe/ga
uge correspondence. These interfaces\, viewed as operators on the Hilbert
space\, give linear maps between spaces of SUSY vacua\, understood mathema
tically as generalized cohomology theories of the Higgs branch. A natural
class of interfaces are SUSY Janus interfaces for masses\, with the corres
ponding cohomological maps being either the stable envelopes or the chambe
r R-matrices (both due to Maulik-Okounkov and Aganagic-Okounkov). Thus\, s
uch interfaces (and their collisions) can be used to define actions of the
spectrum generating algebras (such as Yangians) on the "gauge" side of th
e Bethe/gauge correspondence\, i.e.\, in QFT. Further applications and pos
sible generalizations will be mentioned as well.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:GONG SHOW
DTSTART:20211125T144500Z
DTEND:20211125T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/54
DESCRIPTION:Title: LIJC Gong Show\nby GONG SHOW as part of London Integrability Jour
nal Club\n\n\nAbstract\nSchedule :\n\n14:45 - 15:00 Meer Ashwinkuma
r\n\n15:00 - 15:15 Levente Pristyák\n\n15:15 - 15:30 Xinyu
Zhang\n\n15:30 - 15:45 Coffee break/Discussion\n\n15:45 - 16:00
Carlos Bercini\n\n16:00 - 16:15 Aleix Gimenez-Grau\n\n16:15
- 16:30 Himanshu Khanchandani\n\n16:30 - 16:45 Discussion\n
\n\nMeer Ashwinkumar\, Kavli Inst. Tokyo\, "Three-dimensional WZW model a
nd the R-matrix of the Yangian"\n\nCarlos Bercini\, ICTP-SAIFR\, "The Wils
on Loop - Large Spin OPE Dictionary"\n\nAleix Gimenez-Grau\, DESY\, "Boots
trapping holographic defect correlators"\n\nHimanshu Khanchandani\, Prince
ton Univ.\, "CFT in AdS and Gross-Neveu BCFT"\n\nLevente Pristyák\, Budap
est Univ.\, "Current operators in the XYZ model"\n\nXinyu Zhang\, DESY\, "
Hidden symmetry in 4d N=2 quiver gauge theory"\n\nAbstracts can be found i
n the Gong Show section of the LIJC website.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roland Bittleston (Perimeter Inst. Theor. Phys.)
DTSTART:20211209T154500Z
DTEND:20211209T173000Z
DTSTAMP:20260404T111134Z
UID:LIJC/55
DESCRIPTION:Title: Bosonic string from Beltrami Chern-Simons\nby Roland Bittleston (
Perimeter Inst. Theor. Phys.) as part of London Integrability Journal Club
\n\n\nAbstract\nIt is well understood how the 2d free scalar CFT emerges f
rom 3d Chern-Simons theory with chiral boundary conditions. Adapting a rec
ent proposal of Costello and Stefański\, I will show how bosonic string t
heory can be obtained from this description by coupling to a dynamical Bel
trami differential in the 3d theory. In particular\, I will show how this
Beltrami differential restores worldsheet diffeomorphism and Weyl invarian
ce in the 2d theory\, and recover the Polyakov action explicitly. By rewri
ting the theory in the BV formalism\, I will show how the bc ghost system
arises from the 3d perspective. Finally\, if there is sufficient time\, I
’ll provide the 3d realization of vertex operators. This talk is based o
n work in progress with Kevin Costello and Bogdan Stefański.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Benjamin Doyon
DTSTART:20211118T154500Z
DTEND:20211118T173000Z
DTSTAMP:20260404T111134Z
UID:LIJC/57
DESCRIPTION:Title: Correlation functions of twist fields from hydrodynamics\nby Benj
amin Doyon as part of London Integrability Journal Club\n\n\nAbstract\nThe
Euler-scale power-law asymptotics of space-time correlation functions in
many-body systems\, quantum and classical\, can be obtained by projecting
the observables onto the hydrodynamic modes admitted by the model and stat
e. This is the Boltzmann-Gibbs principle\; it works for integrable and non
-integrable models alike. However\, certain observables\, such as some ord
er parameters in thermal of generalised Gibbs ensembles\, do not couple to
any hydrodynamic mode: the Boltzmann-Gibbs principle gives zero. I will e
xplain how hydrodynamics can still give the leading exponential decay of o
rder parameter correlation functions. With the examples of the quantum XX
chain and the sine-Gordon model\, I will explain how large deviations of t
he spin and U(1) current fluctuations are related to such exponential deca
y. Exact predictions are given by the ballistic fluctuation theory based o
n generalised hydrodynamics. In the XX model\, this is in agreement with r
esults obtained previously by a more involved Fredholm determinant analysi
s and other techniques\, and even gives a new formula for a parameter regi
me not hitherto studied. In the sine-Gordon model\, these are new results\
, inaccessible by other techniques. Works in collaboration with Giuseppe D
el Vecchio Del Vecchio\, and Márton Kormos.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jakub Vošmera (ETH Zurich)
DTSTART:20211202T144500Z
DTEND:20211202T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/58
DESCRIPTION:Title: D-branes in AdS3xS3xT4 at k=1 and their holographic duals\nby Jak
ub Vošmera (ETH Zurich) as part of London Integrability Journal Club\n\n\
nAbstract\nFollowing the recent work of Eberhardt\, Gaberdiel and Gopakuma
r\, exact comparison between various quantities living on the two sides of
the AdS/CFT duality has become a possibility. The goal of this talk will
be to extend the existing holographic dictionary to include some non-pertu
rbative vacua on both sides. I will start by reviewing the original\, pure
ly closed-string setup\, giving arguments that string theory on ${\\rm AdS
}_3\\times {\\rm S}^3 \\times \\mathbb{T}^4$ with minimal $k=1$ NS-NS flux
is exactly dual to the symmetric-product orbifold CFT with the $\\mathbb{
T}^4$ as the seed. I will then construct various D-branes of this string t
heory and calculate their associated cylinder amplitudes. We will observe
that these amplitudes match with the cylinder correlators of certain bound
ary states of the dual CFT\, thus suggesting a direct correspondence betwe
en these boundary conditions. I will also show that the disk amplitudes of
these D-branes localise to those points in the worldsheet moduli space wh
ere the worldsheet disk holomorphically covers the spacetime disk. This ta
lk is based on https://arxiv.org/abs/2110.05509.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arkady Tseytlin (Imperial Coll.\, London)
DTSTART:20220127T144500Z
DTEND:20220127T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/59
DESCRIPTION:Title: Wilson loop in general representation and RG flow in 1d defect QFT\nby Arkady Tseytlin (Imperial Coll.\, London) as part of London Integrab
ility Journal Club\n\n\nAbstract\nThe generalized Wilson loop operator int
erpolating between the supersymmetric and the ordinary Wilson loop in N=4
SYM theory provides an interesting example of renormalization group flow o
n a line defect: the scalar coupling parameter \\zeta has a non-trivial be
ta function and may be viewed as a running coupling constant in a 1d defec
t QFT.\nWe continue the study of this operator\, generalizing previous res
ults for the beta function and Wilson loop expectation value to the case o
f an arbitrary representation of the gauge group and away from the planar
limit. Focusing on the scalar ladder limit where the generalized Wilson lo
op reduces to a purely scalar line operator in a free adjoint theory\, and
\nspecializing to the case of the rank k symmetric representation of SU(N)
\, we also study a certain ``semiclassical'' limit where k is taken to inf
inity with k \\zeta^2 fixed. This limit can be conveniently studied using
a 1d defect QFT representation in terms of path integral over N commuting
1d bosons. Using this representation\, we compute the beta function and ci
rcular loop expectation value in the large k limit\, and use it to derive
constraints on the structure of the beta function for general representati
on. We discuss the corresponding 1d RG flow and comment on the consistenc
y of the results with the 1d defect version of the F-theorem.\n \nbased on
joint work with Matteo Beccaria and Simone Giombi\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Juan Miguel Nieto García (Surrey U.\, Math. Stat. Dept.)
DTSTART:20220203T144500Z
DTEND:20220203T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/60
DESCRIPTION:Title: Jordan blocks and the Bethe ansatz: The eclectic spin chain as a limi
t\nby Juan Miguel Nieto García (Surrey U.\, Math. Stat. Dept.) as par
t of London Integrability Journal Club\n\n\nAbstract\nIn this talk\, I wil
l present a procedure to extract the generalised eigenvectors of a non-dia
gonalisable matrix by considering a diagonalisable perturbation of it and
computing the non-diagonalisable limit of its eigenvectors. As an example\
, I will show how to compute a subset of the spectrum of the eclectic spin
chain by computing the appropriate limit of the Bethe states of a twisted
su(3) spin chain.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Vegh (Queen Mary\, U. of London)
DTSTART:20220210T150000Z
DTEND:20220210T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/61
DESCRIPTION:Title: The spectral curve of segmented strings\nby David Vegh (Queen Mar
y\, U. of London) as part of London Integrability Journal Club\n\n\nAbstra
ct\nIn this talk\, I will discuss how to compute the spectral curve of ``s
egmented strings'' in AdS_3. The motion of a string in this target space i
s integrable and the worldsheet theory can be discretized while preserving
integrability. The corresponding embeddings are segmented strings\, which
generalize piecewise linear strings in flat space. I will present several
examples. Next\, I will introduce ``brane tilings''\, which are doubly-pe
riodic planar bipartite graphs. I will show that the motion of a closed se
gmented string can be embedded into the mutation dynamics of a certain bra
ne tiling. This will enable us to compute the spectral curve by taking the
determinant of the dressed adjacency matrix of the tiling.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gregory Korchemsky (IPhT Saclay)
DTSTART:20220217T144500Z
DTEND:20220217T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/62
DESCRIPTION:Title: Applications of strong Szego limit theorem in AdS/CFT\nby Gregory
Korchemsky (IPhT Saclay) as part of London Integrability Journal Club\n\n
\nAbstract\nI will review a recent progress in computing four-point correl
ation functions of infinitely heavy half-BPS operators in planar N = 4 SYM
. Taking advantage of integrability of the theory\, these correlation func
tions can be constructed in terms of fundamental building blocks - the oct
agon form factors. We show that the octagon form factor can be expressed a
s a Fredholm determinant of an integrable Bessel operator and demonstrate
that this representation is very efficient in finding its dependence on th
e ’t Hooft coupling and two cross ratios. At weak coupling\, this yields
a known series representation of the octagon in terms of ladder integrals
. At strong coupling\, we apply strong Szego limit theorem to develop a sy
stematic expansion of the octagon in the inverse powers of the coupling co
nstant and calculate accompanying expansion coefficients analytically.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Caetano
DTSTART:20220224T144500Z
DTEND:20220224T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/63
DESCRIPTION:Title: Crosscap States in Integrable Theories\nby Joao Caetano as part o
f London Integrability Journal Club\n\n\nAbstract\nIn this talk\, I will d
escribe crosscap states in integrable field theories and spin chains in 1+
1 dimensions. I will derive an exact formula for overlaps between the cros
scap state and any excited state in integrable field theories with diagona
l scattering. I will then compute the crosscap entropy\, i.e. the overlap
for the ground state\, in some examples. In the examples analyzed\, the re
sult turns out to decrease monotonically along the renormalization group f
low except in cases where the discrete symmetry is spontaneously broken in
the infrared. I will discuss crosscap states in integrable spin chains\,
and obtain determinant expressions for the overlaps with energy eigenstate
s. I will comment on the realization of crosscap states in holography.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Riccardo Borsato (Santiago de Compostela U.\, IGFAE)
DTSTART:20220303T144500Z
DTEND:20220303T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/64
DESCRIPTION:Title: Homogeneous Yang-Baxter deformations as undeformed yet twisted models
\nby Riccardo Borsato (Santiago de Compostela U.\, IGFAE) as part of L
ondon Integrability Journal Club\n\n\nAbstract\nI will review recent progr
ess in the study of a class of integrable deformations of sigma models kno
wn as "homogeneous Yang-Baxter". These deformations can be understood as g
eneralisations of the well known TsT transformations. In fact\, rather tha
n deformations\, the homogeneous Yang-Baxter procedure too can be reinterp
reted as imposing twisted worldsheet boundary conditions in the undeformed
sigma model. I will explain how to construct the twist in the generic cas
e\, which generalises the twist of TsT from abelian to non-abelian. I will
also use the expression for the twist to discuss the construction of the
classical spectral curve in some examples. To conclude\, I will mention so
me open questions related to the quantum integrability of these models.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Guica
DTSTART:20220317T144500Z
DTEND:20220317T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/65
DESCRIPTION:by Monica Guica as part of London Integrability Journal Club\n
\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Troels Harmark
DTSTART:20220324T144500Z
DTEND:20220324T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/66
DESCRIPTION:by Troels Harmark as part of London Integrability Journal Club
\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/66/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shai M. Chester (Weizmann Inst.)
DTSTART:20220310T144500Z
DTEND:20220310T163000Z
DTSTAMP:20260404T111134Z
UID:LIJC/67
DESCRIPTION:Title: Bootstrapping N = 4 super-Yang-Mills on the conformal manifold\nb
y Shai M. Chester (Weizmann Inst.) as part of London Integrability Journal
Club\n\n\nAbstract\nWe study the N = 4 SYM stress tensor multiplet 4-poin
t function for any value of the complexified coupling tau\, and in princip
le any gauge group (we focus on SU(2) and SU(3) for simplicity). By combin
ing non-perturbative constraints from the numerical bootstrap with two exa
ct constraints from supersymmetric localization\, we are able to compute u
pper bounds on low-lying CFT data (e.g. the Konishi) for any value of tau.
These upper bounds are very close to the 4-loop weak coupling predictions
in the appropriate regime. We also give preliminary evidence that these u
pper bounds become small islands under reasonable assumptions\, in which c
ase our method would provide a numerical solution to N = 4 SYM for any gau
ge group and tau.\n
LOCATION:https://stable.researchseminars.org/talk/LIJC/67/
END:VEVENT
END:VCALENDAR