Title: Dynamics near a holographic first order phase transit ion

\nAbstract:

\nIn this talk I will discuss our recent work on time dependent dynamics for theories with a first order phase transitio n using a holographic description. I will make a brief review of our previ ous work on holographic phase separation which leads to a coupleof questio ns. In particular I will analyze the collisions and merging of domains of different phases\, boost invariant evolution and some conclusions for the future study of the dynamics of a confinement-deconfinement transition.

DTSTART;TZID=Asia/Jerusalem:20200211T103000 DTEND;TZID=Asia/Jerusalem:20200211T113000 SEQUENCE:0 SUMMARY:Romuald Janik URL:https://phsites.technion.ac.il/strings/event/romuald-janik/ END:VEVENT BEGIN:VEVENT UID:4ohu1rj7ln09c5jpg751hrmhg0@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: The “Hubble Tension”: a growing disagreement between early and late Universe observations

\nAbstract:

\nThere are
two approaches to estimating the current expansion rate of the Universe\,
which is parametrised by the Hubble constant H0. One attempts to measure i
t directly (the most famous example of which relies on calibrating a dista
nce ladder towards standard-candletype-Ia supernovae in our local cosmic n
eighbourhood). The other is to predict its value based on information from
the distant early Universe (such as the baryon acoustic oscillation scale
\, which can be extracted from cosmic microwave background measurements)an
d assuming the standard cosmological model\, known as ΛCDM. One of the mos
t pressing mysteries in cosmology today is why H0 measurements based on th
ese two approaches are growing in tension (the most recent assessments are
up to ~5sigma discrepant)\, possiblyhinting at a failure of ΛCDM.

\n
I will describe the current status of different measurements of the expans
ion rate (based on a wide range of observables)\, point out their caveats
and outline their prospects for improvement. From the theoretical point of
view\, I will motivate a usefulway of reframing the tension\, and discuss
the clues we have towards solving it with new physics beyond ΛCDM.

Title: Random boundary geometry and gravity dual of $Tbar{T}
$ deformation

\nAbstract: We study the random geometry approach to th
e $Tbar{T}$ deformation of 2d conformal field theory developed by Cardy an
d discuss its realization in a gravity dual. In this representation the gr
avity dual of the $Tbar{T}$ deformation becomes a straightforward translat
ion of the field theory language and the dual geometry is AdS$_3$ or BTZ b
lack holes without a finite cutoff but instead with random boundary diffeo
morphisms\, reflecting an increase of degrees of freedom in the flow to th
e UV by an irrelevant geometric $Tbar{T}$ operator. We streamline the meth
od of computation and calculate the energy spectrum and the thermal free e
nergy in a manner that can be directly translated into the gravity dual la
nguage. We further generalize this approach to correlation functions and r
eproduce the all-order result with universal logarithmic corrections compu
ted by Cardy in a different method. Thus this version of gravity dual of t
he $Tbar{T}$ deformation works not only for the energy spectrum and the th
ermal free energy but also for correlation functions.

The title: “A new topological symmetry of asymptotically fl at spacetimes”

\nI will show that asymptotically flat spacetimes are invariant\, in addition to the BMS group\, under a new dual supertranslat ion symmetry. The corresponding new conserved charges are akin to the larg e magnetic U(1) charges in QED and they reveal a rich topologicalstructure exhibited by the asymptotic metric as well as by the Hilbert space of asy mptotic states. Among the results that I will describe in this talk are th e construction of a gravitational-magnetic monopole solution analogous to the Wu-Yang monopole in QEDand the discovery of a new gravitational dualit y akin to electric-magnetic duality in field theory.

DTSTART;TZID=Asia/Jerusalem:20200225T113000 DTEND;TZID=Asia/Jerusalem:20200225T123000 SEQUENCE:0 SUMMARY:Uri Kol NYU URL:https://phsites.technion.ac.il/strings/event/uri-kol-nyu/ END:VEVENT BEGIN:VEVENT UID:3238fsfbmi3ucq6t8vgs9kbt1r@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Instantons in five-dimensional O(N) vector models

\nAbstract: In this talk\, I will review the construction of O(N) vec tor models above four dimensions\, and explain why one might think that\, in five dimensions\, there should exist O(N)-invariant CFTs at sufficientl y large N. However\, a closer look at theseconstructions reveals that the CFTs are non-unitary because instanton effects lead to small imaginary pa rts of scaling dimensions and OPE coefficients.

DTSTART;TZID=Asia/Jerusalem:20200317T103000 DTEND;TZID=Asia/Jerusalem:20200317T113000 SEQUENCE:0 SUMMARY:Silviu Pufu\, Princeton (Postponed due to corona) URL:https://phsites.technion.ac.il/strings/event/ramy-brustein-4/ END:VEVENT BEGIN:VEVENT UID:28jg4qsbm6uot5o98p235hb790@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: 5d SCFTs and Graphs

\nAbstract:

\nI will
give an overview of recent progress towards classifying 5d N=1 SCFTs. The
main tool is the realization in terms of M-theory on singular Calabi-Yau t
hree-folds\, however we abstract the information about the UV fixed points
into graphs\, and explain howthese encode RG-flows between 5d SCFTs\, wea
kly coupled descriptions as well as dualities.

Title: 5d SCFTs and Graphs

\nI will give an overview o f recent progress towards classifying 5d N=1 SCFTs. The main tool is the r ealization in terms of M-theory on singular Calabi-Yau three-folds\, howev er we abstract the information about the UV fixed points into graphs\, and explain howthese encode RG-flows between 5d SCFTs\, weakly coupled descri ptions as well as dualities.

DTSTART;TZID=Asia/Jerusalem:20200331T113000 DTEND;TZID=Asia/Jerusalem:20200331T123000 SEQUENCE:0 SUMMARY:Sakura Schafer-Nameki\, Oxford URL:https://phsites.technion.ac.il/strings/event/avner-karasik-cambridge/ END:VEVENT BEGIN:VEVENT UID:527joup135vh5b638j9pt1ids2@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title:Continuum Quantum Field Theories for Fractons

\nAbstract: Starting with a lattice system at short distances\, its long-dis tance behavior is captured by a continuum Quantum Field Theory (QFT). Thi s description is universal\, i.e. it is independent of most of the details of the microscopic system. Surprisingly\, certain recently discovered lat tice systems\, and in particular models of fractons\, seem to violate this general dogma. Motivated by this apparent contradiction\, we will presen t exotic continuum QFTs that describe these systems.

\n\nThis will b e a zoom joint seminar. The link will be sent to the regular participants of the joint seminar. Other people who are interested to attend it send a message to

\n DTSTART;TZID=Asia/Jerusalem:20200421T150000 DTEND;TZID=Asia/Jerusalem:20200421T160000 SEQUENCE:0 SUMMARY:Nathan Seiberg\, IAS URL:https://phsites.technion.ac.il/strings/event/nathan-seiberg-ias-2/ END:VEVENT BEGIN:VEVENT UID:4t6a2ba89bqcu73lthbjp8p30h@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Slava Rychkov (IHES\, Bures-sur-Yvette)

\ntitle:

Supersymmetry and its absence in the Random Field Ising Model.

Ab
stract:

We will discuss the phase transition in the Ising model with
magnetic impurities. By one kind of lore\, this leads to a non-unitary sup
ersymmetric CFT with scalar supercharges (Parisi-Sourlas supersymmetry). B
y further lore\, Parisi-Sourlas SCFTin D dimensions is equivalent to a non
-SUSY CFT in D-2 dimensions. It is known that this story is not fully corr
ect\, but we will put some of it on firmer ground using non-perturbative C
FT methods\, and we will propose a scenario for why the full conjecture is
failing. Joint work with Apratim Kaviraj and Emilio Trevisani.

This will be a zoom joint seminar. The link will be sent to the regular participants of the joint seminar. Other people who ar e interested to attend it send a message to

\n DTSTART;TZID=Asia/Jerusalem:20200505T113000 DTEND;TZID=Asia/Jerusalem:20200505T123000 SEQUENCE:0 SUMMARY:Slava Rychkov\, IHES\, Bures-sur Yvette URL:https://phsites.technion.ac.il/strings/event/slava-rychkov-ihes-ens/ END:VEVENT BEGIN:VEVENT UID:4f0pd6ra7ecda1fq4dahp21n0m@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:title: Holographic Pseudo Entropy

\nabstract: In this
talk\, we will study a generalization of holographic entanglement entro

\npy. This quantity is defined by a mininal area surface in an asymptot
icaly AdS

\n space with Euclidean time-dependence. We will give its C
FT counterpart\, which

\n we call pseudo entropy. We will also provid
e quantum information theoretic in

\nterpretations of this quantity i
n several specific examples of qubit systems\,

\nwhich help us to und
erstand our results of pseudo entropy in CFTs and gravity

\nduals. <
/p>
DTSTART;TZID=Asia/Jerusalem:20200512T110000
DTEND;TZID=Asia/Jerusalem:20200512T120000
SEQUENCE:0
SUMMARY:Tadashi Takayanagi\, YITP Kyoto
URL:https://phsites.technion.ac.il/strings/event/tadashi-takayanagi-yitp-ky
oto/
END:VEVENT
BEGIN:VEVENT
UID:3215e6ltd0htfal4g4q6sjlo0p@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:

title: “Holographic renormalization group flows on curved ma nifolds and F-theorems”

\n\nAbstract: Holographic RG flows will be studied where the QFT is both on flat and curved manifolds\, and their ge neral structure will be analyzed.

\nQuantum phase transitions driven by curvature will be found and studied.

\nThe results will be used to propose new F-functions in 3 dimensions that may be generalizable also to higher dimensions.

\n\nThis will be a zoom joint seminar. The lin k will be sent to the regular participants of the joint seminar. Other pe ople who are interested to attend it send a message to

\n DTSTART;TZID=Asia/Jerusalem:20200519T110000 DTEND;TZID=Asia/Jerusalem:20200519T120000 SEQUENCE:0 SUMMARY:Elias Kiritsis\, Crete U.\, APC Paris URL:https://phsites.technion.ac.il/strings/event/elias-kiritsis-crete-u-apc -paris/ END:VEVENT BEGIN:VEVENT UID:0js5bb3a1hutkh6mqkp8p1frmu@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title – An Analytical Toolkit for the S-matrix Bootstrap

\nAbstract – Motivated by the success of the conformal bootstrap\, we re
visit the implications of elastic unitarity and extended analyticity for t
he S-matrix of unitary\, relativistic\, gapped theories in d>2 spacetime d
imensions. We consider two natural expansion of the non-perturbative ampli
tude — the threshold and the large spin expansions\, as well as the relati
on between them. Finally\, we discuss the implication of these to the nume
rical S-matrix bootstrap.

Title: An overview of the Swampland

\nAbstract:The Swampland program aims at distinguishingeffective theo ries which can be consistently completed into quantum gravity in the ultra violet from those which cannot. The main objective of this talk is to pres ent an introduction to the field. I will also present a brief overview of some recentwork which proposes and tests some Swampland constraints\ , specifically relating to scale separation in anti-deSitter spaces and to the presence of gravitational instanton corrections in super symmetric theories.

\n DTSTART;TZID=Asia/Jerusalem:20200602T113000 DTEND;TZID=Asia/Jerusalem:20200602T123000 SEQUENCE:0 SUMMARY:Eran Palti BGU\, MPI Munich URL:https://phsites.technion.ac.il/strings/event/eran-palti-bgu-mpi-munich/ END:VEVENT BEGIN:VEVENT UID:13pdh3246k1ndvcu5iu869db9f@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title
:\n

Color Con
finement and Bose-Einstein Condensation\n

\n

Abstract: \n

We argue that partially-confined\, partial
ly-deconfined phase\, in which SU(M) subgroup of SU(N) gauge group deconfi
nes\, exists between completely confined phase and completely deconfinedph
ases. In the weak-coupling regime\, we describe this phase analytically\,
by using the techniques developed by Aharony and collaborators in 2003. (I
f time permits\, we show the evidence at strong coupling as well\, by usin
g the Monte Carlo method.) Based on this”partial confinement” picture\, we
propose a unified description of color confinement in the large-N gauge t
heory and Bose-Einstein condensation (BEC) in the system of identical boso
ns. Indistinguishability associated with the symmetry group — SU(N) in gau
getheory\, and S_N permutations in the system of identical bosons — is cru
cial for the formation of the condensed (confined) phase. We relate standa
rd criteria\, based on off-diagonal long range order (ODLRO) for BEC and t
he Polyakov loop for gauge theory. Theconstant offset of the distribution
of the phases of the Polyakov loop corresponds to ODLRO. This viewpoint ma
y have implications for confinement at finite N\, and for quantum gravity
via gauge/gravity duality.
DTSTART;TZID=Asia/Jerusalem:20200609T113000
DTEND;TZID=Asia/Jerusalem:20200609T123000
SEQUENCE:0
SUMMARY:Masanori Hanada\, ( Southampton U.\, Surrey U.
URL:https://phsites.technion.ac.il/strings/event/masanori-hanada-southampto
n-u-surrey-u/
END:VEVENT
BEGIN:VEVENT
UID:2qprpg6kb047d0qe9sqop1c9qa@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:**
DTSTART;TZID=Asia/Jerusalem:20200901T150000
DTEND;TZID=Asia/Jerusalem:20200901T160000
SEQUENCE:0
SUMMARY:Zohar Komargodski
URL:https://phsites.technion.ac.il/strings/event/zohar-komargodski-3/
END:VEVENT
BEGIN:VEVENT
UID:7m7knk2dpqb2ie345crbc4403b@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:****Title: Quantum Extremal Islands Made Easy**\n**Title: Flux-based statistical prediction of three-body o
utcomes**\n**\n****Abstract: The three-body problem in Newtonian
gravity is one of the oldest and richest problems in physics. Giants work
ed on it and it served as the source of numerous fields in theoretical phy
sics and mathematics including perturbation theory\, topology and chaos. Y
et\, it remains unsolved\, and up to this work\, the associated statistica
l theory was incomplete and flawed. **\n**Here\, I present a reduct
ion of the differential decay rate in a factorized form. One factor is the
flux of phase-space volume\, rather than the volume itself which was used
in all previous works\, and it is given in a cutoff-independent closed-fo
rm. The other factor is related to the chaotic absorptivity and to Kirchho
ff’s law of thermal radiation\, also known as greybody radiation. Numerica
l evidence will be presented. I believe that this exact factorization crac
ks the problem and would allow future progress. Based on https:
//arxiv.org/abs/2002.11496**
DTSTART;TZID=Asia/Jerusalem:20201103T160000
DTEND;TZID=Asia/Jerusalem:20201103T170000
SEQUENCE:0
SUMMARY:Barak Kol
URL:https://phsites.technion.ac.il/strings/event/barak-kol-2/
END:VEVENT
BEGIN:VEVENT
UID:6nvnhudfgkgeld3o7m5mu5uc0q@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:**Title: The Statistical Mechanics of Near-BPS Black Holes
**\n**\n****Abstract: The status of near extremal black holes in
gravity and string theory has long remained unclear due to the failure of
black hole thermodynamics at low temperatures. Such black holes have an A
dS2 region\, and substantial progress in the last few years has been made
on Jackiw-Teitelboim (JT) dilaton gravity\, which is an effective theory o
f nearly AdS2 spacetimes dual to a 1D “Schwarzian” theory. **\n

D-instantons perturbation theory

DTSTART;TZID=Asia/Jerusalem:20200616T113000 DTEND;TZID=Asia/Jerusalem:20200616T123000 SEQUENCE:0 SUMMARY:Asoke Sen\, Harish-Chandra Res. Inst URL:https://phsites.technion.ac.il/strings/event/asoke-sen-harish-chandra-r es-inst/ END:VEVENT BEGIN:VEVENT UID:4m7dpk42lfc7qgk2visrvek094@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Boundary Conditions for Chiral Fermions

\nAbstr
act: Iʼll describe boundary conditions for fermions in d=1+1\,

\ndime
nsions\, using the framework of boundary conformal field theory. Iʼll

\nexplain how boundary states are classified by a mod 2 index\, related t
o

\ntheir SPT phase\, describe how one can follow RG flows from one b
oundary

\nstate to another\, and give a novel perspective on the Z_8
classification

\nof d=2+1 SPT phases

Title:

\nModularity of supersymmetric partition functi ons

\nAbstract:

\nIn this talk\, I will present a novel modula
r property of 4d N=1

\nsupersymmetric partition functions of supersym
metric theories with R-symmetry. It is a generalization of the modular inv
ariance of the supersymmetric partitionfunction of two-dimensional supersy
mmetric theories on a torus i.e. of the elliptic genus. It comes from requ
iring consistency of partitionfunctions under gluing and\, among other thi
ngs\, can be used to rederive the supersymmetric Cardy formula for four-di
mensional gaugetheories that has played a key role in computing the entrop
y of supersymmetric black holes.

Title: Deformations of JT Gravity and Matrix Models\,

\n \nAbstract: I will explain how the relation between two-dimensional J T gravity and a matrix model — that is a

\nrandom ensemble of quantu m systems rather than a specific quantum system — can be generalized

\nwhen one perturbs the action of JT gravity to a more generic case. Based on arXiv:2006.13414.

\nSee also arXiv:2006.11317 by Maxfield a nd Turiaci.

\n\nAnybody who is not on the list of the Israel string joint seminar and would like to listen to this seminar send your email to cobi@tauex.tau.ac.il and you will receive the zoom link

DTSTART;TZID=Asia/Jerusalem:20200804T160000 DTEND;TZID=Asia/Jerusalem:20200804T170000 SEQUENCE:0 SUMMARY:Edward Witten URL:https://phsites.technion.ac.il/strings/event/edward-witten/ END:VEVENT BEGIN:VEVENT UID:3ng7jeutgnf09pd29snnkn2l9b@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: “Non-Symmetries and 2-Dimensional QCD” ?Abstract :**\nWe will review the subject of “non-symmetries’’ or “defect symmetrie
s.” We will argue that massless two dimensional QCD admits exponentially m
any such symmetries and we use them to prove deconfinement as well as to c
ompute exactly the tension of thestring in the small mass limit. **

title: “Humanly traversable wormholes”

DTSTART;TZID=Asia/Jerusalem:20200908T160000 DTEND;TZID=Asia/Jerusalem:20200908T170000 SEQUENCE:0 SUMMARY:Juan Maldacena URL:https://phsites.technion.ac.il/strings/event/juan-maldacena/ END:VEVENT BEGIN:VEVENT UID:11k9cfdor28oebf2dbe1ci9jiu@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Partition functions of the tensionless string

\nAbstract: I discuss string theory on AdS3xS3xT4 in the tensionless limit\ ,with one unit of NS-NS flux. This theory is conjectured to be dual to the symmetric product orbifold CFT. I show how to compute the full string par tition function on various locally AdS3 backgrounds\, such as thermal AdS3 \, the BTZ black and conical defects\,and find that it is independent of t he actual background\, but only depends on the boundary geometry. Conseque ntly\, reproducing the boundary partition function does not require a sum over bulk geometries\,but rather agrees with the string partition function on any bulk geometry with the appropriate boundary. I argue that the same mechanism shows the factorization of the bulk partition function when geo metries with disconnected boundaries are considered.

DTSTART;TZID=Asia/Jerusalem:20200915T113000 DTEND;TZID=Asia/Jerusalem:20200915T123000 SEQUENCE:0 SUMMARY:Lorenz Eberhardt URL:https://phsites.technion.ac.il/strings/event/lorenz-eberhardt/ END:VEVENT BEGIN:VEVENT UID:3adpt8bs4gi6lm00l1cipqq752@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title:

\nMerging Swampland Conjectures using strings a nd membranes

\nAbstract:

\nIn this talk I will discuss new rela
tions that appear among the Swampland Conjectures when analysing the prope
rties of low codimension BPS objects\, in particular strings and membranes
in N=1 4D EFTs. I will review the state of the art of the Swamplandprogra
m and revisit the most important conjectures\, namely the Weak Gravity Con
jecture (WGC) and the Swampland Distance Conjecture (SDC). Then I will des
cribe how to apply the WGC to low codimension BPS objects by interpreting
the 4d backreaction of these objectsas a classical RG flow of their coupl
ings. Constraints on the UV charges and tensions get then translated to co
nstraints on the axionic kinetic terms and scalar potential of the EFT\, w
hich uncovers new relations among the Swampland Conjectures. In particular
\,we show that the WGC for strings implies the SDC\, by using that infinit
e distance limits can be realised as RG flow endpoints of fundamental axio
nic strings. Similarly\, WGC-saturating membranes generate a scalar potent
ial satisfying the de Sitter Conjecture.

Title:Reggeized scattering\, entanglement and chaos using AdS/CFT\n

ABSTRACT:The eikonalized parton-parton scattering ampl itude at large energy and\n

large impact parameter\, is dominat ed by the exchange of a hyperbolic surface in\n

walled AdS. It s analytical continuation yields a worldsheet instanton that is\n

at the origin of the Reggeization of the amplitude and a thermal-like < /pre>\n

quantum entropy. I will construct the entangled density matri x following from the\n

exchanged surface\, and show that its vo n-Neumann entanglement entropy\n

coincides with its thermal-lik e entropy. The ratio of the entanglement entropy\n

to the tran sverse growth of the exchanged surface is similar to the Bekenstein\n

entropy ratio for a black-hole\, with a natural definition of satu ration\n

and the on-set of chaos in high energy collisions. Th e largest eigenvalues\n

of the entangled density matrix obey a cascade equation in rapidity\,\n

reminiscent of non-linear QCD evolution of wee-dipoles\n

at low-x and weak coupling. We su ggest that the largest eigenvalues\n

describe the probability distributions of wee-quanta at low-x\n

and strong coupling that maybe measurable at present and future hadron-hadron\n

and le pton- hadron colliders.DTSTART;TZID=Asia/Jerusalem:20200929T160000 DTEND;TZID=Asia/Jerusalem:20200929T170000 SEQUENCE:0 SUMMARY:Ismail Zahed URL:https://phsites.technion.ac.il/strings/event/ismail-zahed/ END:VEVENT BEGIN:VEVENT UID:4nq1jjjk2i3p5qm94c8adn9ahh@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:

Title: Landau diagrams in AdS and S-matrices from conformal correlators

\nAbstract: Quantum field theories in AdS generate confo rmalcorrelation functions on the boundary\, and in the limit where AdS is nearly flat one should be able to extract an S-matrix from such correlator s. We discuss a particularly simple position-space procedure to do so. It features a direct map from boundary positionsto (on-shell) momenta and the reby relates cross ratios to Mandelstam invariants. This recipe succeeds i n several examples\, includes the momentum-conserving delta functions\, an d can be shown to imply the two proposals based on Mellin space and on the OPE data.Interestingly the procedure does not always work: the Landau sin gularities of a Feynman diagram are shown to be part of larger regions\, t o be called `bad regions’\, where the flat-space limit of the Witten diagr am diverges. To capture these divergences we introducethe notion of Landau diagrams in AdS. As in flat space\, these describe on-shell particles pro pagating over large distances in a complexified space\, with a form of mom entum conservation holding at each bulk vertex. As an application we recov er the anomalousthreshold of the four-point triangle diagram at the bounda ry of a bad region.

DTSTART;TZID=Asia/Jerusalem:20201006T160000 DTEND;TZID=Asia/Jerusalem:20201006T170000 SEQUENCE:0 SUMMARY:Shota komatsu URL:https://phsites.technion.ac.il/strings/event/shota-komatsu/ END:VEVENT BEGIN:VEVENT UID:7dg17tuu7lqur4ffc8ihuvpi4i@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Boundary conditions for a free scalar field

\nAbstract:

\nIn the first part of the talk\, I will consider the pro blem of classifying the conformal boundary conditions (b.c.) for the free scalar CFT. We will see how to tackle this problem using conformal bootstr ap techniques. In the case of 4d bulk\, I will show ournumerical results\, which feature a “kink” that indicates the existence of a non-trivial “int eracting” b.c.\, besides the obvious Neumann and Dirichlet “free” b.c.’s.< /p>\n

In the second part of the talk\, I will discuss the RG flow of a 4d free scalar field coupled to large N vector models on the boundary. The (classically marginal) coupling involves the boundary mode of the scalar and the O(N) single-trace scalar operator. Iwill explain that the resultin g RG connects two fixed points with bulk and boundary decoupled\, and the local 3d sector is the free vector model in one end\, and the critical one in the other end. This same RG admits two weak-strong dual descriptions\, one fromthe free end\, and one from the critical end.

DTSTART;TZID=Asia/Jerusalem:20201013T113000 DTEND;TZID=Asia/Jerusalem:20201013T123000 SEQUENCE:0 SUMMARY:Lorenzo di Pietro URL:https://phsites.technion.ac.il/strings/event/lorenzo-di-pietro-2/ END:VEVENT BEGIN:VEVENT UID:3se4418jbdb5e3chkq5g0h4ob5@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Abstra ct: We illustrate the appearance of quantum extremal islands in holographi c setups in higher dimensions. We emphasize the close parallel with the be haviour of holographic entanglement entropy in more familiar settings.

DTSTART;TZID=Asia/Jerusalem:20201020T160000 DTEND;TZID=Asia/Jerusalem:20201020T170000 SEQUENCE:0 SUMMARY:Rob Myers URL:https://phsites.technion.ac.il/strings/event/rob-myers/ END:VEVENT BEGIN:VEVENT UID:4qlp7q9o9h4r8r9ufgqf6s6ngs@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title : Multi-point Bootstrap (and the se
arch for a single open/closed string description of N=4 SYM)

<
span style='font-family: Tahoma\, Geneva\, sans-serif\, serif\, EmojiFont\
;font-size: 16px'>

Title: The Unreasonab le Effectiveness of Higher-Derivative Supergravity in AdS_4 Holography

\n\nAbstract: I will describe the four-derivative correction s to four-dimensional N=2 minimal gauged supergravity and show that they a re controlled by two constants. Interestingly\, the solutions of the equat ions of motion in the two-derivative theory are not modified by the higher -derivative corrections. I will use this to arrive at a general formula fo r the regularized on-shell action for any asymptotically locally AdS_4 sol ution of the theory and show how the higher-derivative corrections affect black hole thermodynamic quantities in a universal way. I will employ thes e results in the context of holography to derive new explicit results for the subleading corrections in the large N expansion of supersymmetric part ition functions on various compact manifolds for a large class of three-di mensional SCFTs arising from M2- and M5-branes. I will also briefly discus s possible extensions and generalizations of these results.

DTSTART;TZID=Asia/Jerusalem:20201110T160000 DTEND;TZID=Asia/Jerusalem:20201110T170000 SEQUENCE:0 SUMMARY:Nikolay Bobev URL:https://phsites.technion.ac.il/strings/event/nikolay-bobev/ END:VEVENT BEGIN:VEVENT UID:5qp9opsepki5kmkdul47badse3@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Fine probes of quantum chaos

Abst
ract: Quantum chaotic dynamics is associated to diverse physical phenomena
and signatures. In this talk\, we describe progress in building effective
theories for three of these: the butterfly effect\, the pole skipping phe
nomenon\, and thermalization through the lens of entanglement entropy. We
uncover their interplay by showing that the butterfly velocity plays an im
portant role in all three manifestations of chaos. The discussion is infor
med by results from AdS/CFT and from models of SYK type.

Title: Gravity from Averaging CFTs

\nAbstract: I will
explore the idea that certain theories of gravity in Anti-de

\nSitter
space are dual to an average over an ensemble of quantum

\ntheories\
, rather than to a specific quantum theory. I will describe

\nan ave
rage over Narain’s family of two-dimensional conformal field

\ntheori
es which describe free bosons on a torus\, and compute the

\npartitio
n function using the Siegel-Weil formula. The result takes

\nthe for
m of a sum over geometries as one would expect in a theory of

\ngravi
ty. But the gravitational theory looks more like a Chern-Simons

\nth
eory than like Einstein gravity.

Title: Global symmetry\,
Euclidean gravity\, and the black hole information problem

Abstra ct: In this ta lk I will show how the essential ingredients of recent calculations of the Page curve of an evaporating black hole can be usedto generalize a recent argument against global symmetries beyond the AdS/CFT correspondence to m ore realistic theories of quantum gravity\, illustrating a close connectio n between the absence of global symmetries and a unitary resolution of the black hole informationproblem. I’ll also give several low-dimensional exa mples of quantum gravity theories which do not have a unitary resolution o f the black hole information problem\, and which therefore can and do have global symmetries. Motivated by this discussion\, I’ll conjecturethat in a certain sense Euclidean quantum gravity is equivalent to holography. Ba sed on recent work with Edgar Shaghoulian.

DTSTART;TZID=Asia/Jerusalem:20201201T160000 DTEND;TZID=Asia/Jerusalem:20201201T170000 SEQUENCE:0 SUMMARY:Daniel Harlow URL:https://phsites.technion.ac.il/strings/event/daniel-harlow/ END:VEVENT BEGIN:VEVENT UID:0oaogqg6bigrghidoo7djtrofv@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:
\n

In this talk\, we will derive and solve an effective theory to descri be 4D flat space black holes which are just above the BPS bound. This theo ry is an N=4 supersymmetric version of the 2D Jackiw-Teitelboim gravity <- > 1D Schwarzian correspondence which we will obtain from nearly AdS2xS2 bl ack holes in 4D N=2 supergravity. Using the Schwarzian description of thes e low temperature black holes\, we can compute the partition function and density of states exactly. Our results verify several conjectures about ne ar-BPS black holes coming from string theory\, including an exact extremal degeneracy agreeing with Bekenstein-Hawking and a thermodynamic mass gap between extremal and near-extremal black holes.

\n\n

Based
on a recent paper (https://arxiv.org/abs/2011.01953) with
MTH\, Luca Iliesiu\, Gustavo Turiaci\, and Wenli Zhao.
DTSTART;TZID=Asia/Jerusalem:20201208T160000
DTEND;TZID=Asia/Jerusalem:20201208T170000
SEQUENCE:0
SUMMARY:Matthew Heydeman
URL:https://phsites.technion.ac.il/strings/event/tba/
END:VEVENT
BEGIN:VEVENT
UID:6eb4m4cq41v726en27m1iq0f49@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:
DTSTART;TZID=Asia/Jerusalem:20201215T160000
DTEND;TZID=Asia/Jerusalem:20201215T170000
SEQUENCE:0
SUMMARY:Hanukah – no seminar
URL:https://phsites.technion.ac.il/strings/event/hanukah-no-seminar/
END:VEVENT
BEGIN:VEVENT
UID:58avs1pm4kc6rgcoquvkrtbqjr@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:

Title: Photon Ring Autocorrelations\n

\n

\n

Abstract: In the presence of a black hole\, light sources connect
to observers along multiple paths. As a result\, observed brightness fluc
tuations must be correlated across different times and positions in black
hole images. Photons that execute multiple orbits around the black hole ap
pear near a critical curve in the observer sky\, giving rise to the photon
ring. In the talk I will describe the structure of a Kerr black hole’s ph
oton ring. I will then discuss a novel observable we have recently propose
d: the two-point correlation function of intensity fluctuations on the rin
g. I will describe its analytic computation within a toy model of stochast
ic emission\, and show that it exhibits a universal\, self-similar pattern
consisting of multiple peaks of identical shape: while the profile of each
peak encodes statistical properties of fluctuations in the source\, the l
ocations and heights of the peaks are determined purely by the black hole
parameters. Measuring these peaks would demonstrate the existence of the p
hoton ring without resolving its thickness\, and would provide estimates o
f black hole mass and spin. I will discuss some prospective extensions and
generalizations\, and argue that with regular monitoring over sufficiently
long timescales\, this measurement could be possible via interferometric
imaging with modest improvements to the Event Horizon Telescope.
DTSTART;TZID=Asia/Jerusalem:20201222T160000
DTEND;TZID=Asia/Jerusalem:20201222T170000
SEQUENCE:0
SUMMARY:Shahar Hadar
URL:https://phsites.technion.ac.il/strings/event/shahar-hadar/
END:VEVENT
BEGIN:VEVENT
UID:01ofv8ulgsjmkvp95b6v5uf0p9@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:**Title: Twistors\, Integrability and 4d Chern-Simons Theory**\n

\n**Abstract: It has long been known that many classical integrable sy
stems can be obtained as symmetry reductions of the anti-self-dual Yang-Mi
lls equations. Following a suggestion of Costello\, I’ll show that actions
for asd YM arise from holomorphic Chern-Simons theory on twistor space\,
defined with the help of a choice of meromorphic (3\,0)-form. Applying the
symmetry reduction in twistor space\, one instead arrives at the descript
ion of the integrable system in terms of 4d Chern-Simons theory of Costell
o & Yamazaki.**
DTSTART;TZID=Asia/Jerusalem:20210112T160000
DTEND;TZID=Asia/Jerusalem:20210112T170000
SEQUENCE:0
SUMMARY:David Skinner
URL:https://phsites.technion.ac.il/strings/event/david-skinner/
END:VEVENT
BEGIN:VEVENT
UID:3ckfg9f9bu48o2d1r2g1vo7k3k@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:**Title**: Bounds on Regge growth of flat sp
ace scattering from bounds on chaos\n

Title: Thermal order in large N conformal gauge theo
ries

Abstract: Our experience with many physical
systems tells us that usually when a symmetry is spontaneously broken at
low temperatures\, it is restored upon increasing the temperature sufficie
ntly. The abundance of such systems raises the question of whether this i
s a universal feature of all quantum systems. In this talk\, I will presen
t examples of (3+1)-dimensional non-supersymmetric large N gauge theories
which demonstrate violations of the above feature. I will argue that in th
e N tending to infinity limit\, these theories have conformal manifolds wh
ich survive under all loop corrections to the beta functions of the coupli
ngs. I will show that under certain conditions\, a subset of points on suc
h a conformal manifold demonstrates the spontaneous breaking of a global s
ymmetry at all nonzero temperatures. Furthermore\, I will demonstrate that
this symmetry breaking is accompanied by the Higgsing of a subset of gaug
e bosons leading the system to be in a persistent Brout-Englert-Higgs phas
e.

Title: Comments on holographic description of Narain theories.

Abstract: I will discus
s to what extent holographic description of

Narain theories can mimic the convention
al picture of large c

holography with weakly coupled gravity in the bulk. Namely is
it

possibl
e that the effective IR bulk theory consist of “$U(1)$

gravity” amended with some ad
ditional states. This picture leads to a

hypothesis that in the large central charge
limit density of states of

any Narain theory would be bounded by below by that one
of “$U(1)$

gravity.” This immediately implies maximal value of spectral gap of

primary fields
is $Delta_1=c/(2pi e)$. In the rest of the talk I

will discuss self-consistency of t
his picture using quantum code and

chiral CFTs. First\, I will show the proposed pic
ture yields a new

bound on quantum stabilizer codes\, which is compatible with previ
ously

know
n bounds in the literature. Next\, I will discuss variance of the**density of states\
, which for consistency\, must be vanishingly small inthe large $c$ limit. I will c
onsider ensembles of code and chiral
DTSTART;TZID=Asia/Jerusalem:20210105T160000
DTEND;TZID=Asia/Jerusalem:20210105T170000
SEQUENCE:0
SUMMARY:Anatoly Dymarsky
URL:https://phsites.technion.ac.il/strings/event/anatoly-dymarsky-2/
END:VEVENT
BEGIN:VEVENT
UID:1fh61lkvve0kuvd0e9lqg45c72@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:**

\n

Title: Frontiers in Positive Geometry.

\nAbstract: In this talk I will describe work in progress connecting scattering amplitude s to amplituhedra and positive geometries in kinematic space. For N=4 SYM in the planar limit\, I will show how the geometry of the amplituhedron n aturally provides a new approach to non-perturbative physics. I will also describe conjectural all-loop order\, non-planar\, non-supersymmetric amp lituhedra for the tr(phi^3) theory–which are new (generally infinite) poly topes attached to any Riemann surface–and show how the connection to posit ive geometry forces the existence of “gravity” in this setting.

DTSTART;TZID=Asia/Jerusalem:20210119T160000 DTEND;TZID=Asia/Jerusalem:20210119T170000 SEQUENCE:0 SUMMARY:Nima Arkani-Hamed URL:https://phsites.technion.ac.il/strings/event/nima-arkani-hamed/ END:VEVENT BEGIN:VEVENT UID:27v2ufeapa5gqrbp7dpprvt0o9@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Using Soft Hair to Dissolve the Firewall

\nAbst ract: We build on the observation by Hawking\, Perry and Strominger that a global black hole space-time supports a large number of soft hair degrees of freedom to shed new light on the firewall argument by Almheiri\, Marol f\, Polchinski\, and Sully. The soft hair carries a sizable amount of entr opy and is encoded in a transition function that connects the asymptotic a nd near horizon regions. We argue that an infalling observer automaticall y measures the classical value of the soft mode before reachingthe horizon and that this measurement implements a code subspace projection that enab les the reconstruction of interior operators. We use the soft hair dynami cs to introduce an observer dependent notion of the firewall and show that an infalling observer neverencounters a firewall before reaching the sing ularity.

DTSTART;TZID=Asia/Jerusalem:20210126T160000 DTEND;TZID=Asia/Jerusalem:20210126T170000 SEQUENCE:0 SUMMARY:Sabrina Pasterski URL:https://phsites.technion.ac.il/strings/event/sabrina-pasterski/ END:VEVENT BEGIN:VEVENT UID:08b1afn067f5dfgs628qhd7ipm@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION: DTSTART;TZID=Asia/Jerusalem:20210202T093000 DTEND;TZID=Asia/Jerusalem:20210202T103000 SEQUENCE:0 SUMMARY:No seminars in February – semester break URL:https://phsites.technion.ac.il/strings/event/no-seminars-in-february-se mester-break/ END:VEVENT BEGIN:VEVENT UID:371eeh569c8h4j0ftf9pi9nvg4@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Detecting chaos in hydrodynamics

\nAbstract: H ydrodynamics assumes local equilibration and equilibration assumes ergodic mixing driven by chaos — at least in semi-classical systems. For a generi c such system the timescales of macroscopic thermalization and onset of mi croscopic chaos are very different. Nevertheless\, it is a pillar of Boltz mann transport that long-time equilibration can be computed from microscop ic dynamics. We show how in these systems the two timescales are in fact r elated. Moreover\, we show that a similar connection between both scales s urprisingly also exists in extremely strongly coupled systems through a ph enomenon christened pole-skipping in hydrodynamic response.

DTSTART;TZID=Asia/Jerusalem:20210302T160000 DTEND;TZID=Asia/Jerusalem:20210302T170000 SEQUENCE:0 SUMMARY:Koenraad Schalm URL:https://phsites.technion.ac.il/strings/event/koenraad-schalm/ END:VEVENT BEGIN:VEVENT UID:3udiq1p52gpo5opri53ogth979@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: A CFT Distance Conjecture

\nAbs: We formulate conjectures relating the geometry of conformal manifolds to the spectrum o f local operators in conformal field theories in d>2 spacetime dimensions. We focus on conformal manifolds with limiting points at infinite distance with respect tothe Zamolodchikov metric. Our central conjecture is that a ll theories at infinite distance possess an emergent higher-spin symmetry\ , generated by an infinite tower of currents whose anomalous dimensions va nish exponentially in the distance. Our conjecturesare related to the Dist ance Conjecture in the swampland program. We discuss the supporting eviden ce\, their holographic interpretation\, and implications for superconforma l field theories.

DTSTART;TZID=Asia/Jerusalem:20210309T160000 DTEND;TZID=Asia/Jerusalem:20210309T170000 SEQUENCE:0 SUMMARY:Eric Perlmutter URL:https://phsites.technion.ac.il/strings/event/eric-perlmutter/ END:VEVENT BEGIN:VEVENT UID:1rm2m51f17ek51his6qa45a9p1@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Replica wormhole\, Page curve\, global symmetry and r emnant

\nAbstract:

\nA central dogma in the current theoretical
study of black holes is that they can be viewed as an ordinary quantum sy
stem with large degrees of freedom. In the talk I will argue that replica
wormhole gives strong evidence to the central dogma\, including deriving t
he Page curve of the Hawking radiation\, and an explicit construction of a
complete basis of the black hole interior states. We will also comment on
its relation with violation of global symmetry in quantum gravity.

Title: Black hole microstate statistics from Euclidean wormh
oles

\nAbstract: Over the last several years\, it has been shown that
black hole microstate level statistics in various models of 2D gravity ar
e encoded in wormhole amplitudes. These statistics quantitatively agree w
ith predictions of random matrix theory for chaotic quantum systems\; this
behavior is realized since the 2D theories in question are dual to matrix
models. But what about black hole microstate statistics for Einstein gra
vity in 3D and higher spacetime dimensions\, and ultimately in non-perturb
ative string theory? We will discuss progress in these directions. In 3D
\, we compute a wormhole amplitude that encodes the energy level statistic
s of BTZ black holes. In 4D and higher\, we find analogous wormholes whic
h appear to encode the level statistics of small black holes just above th
reshold. Finally\, we study analogous Euclidean wormholes in the low-ener
gy limit of type IIB string theory\; we provide evidence that they encode
the level statistics of small black holes just above threshold in AdS5 x S
5. Remarkably\, these wormholes appear to be stable in appropriate regime
s\, and dominate over brane-anti-brane nucleation processes in the computa
tion of black hole microstate statistics.

Title: Defects and Anomalies in Quantum Field Theories

\nAbstract: I will review some recent developments in understanding the s tructure of anomalies in the presence of defects in CFTs. The defect inser tions lead to new ‘t Hooft anomalies and conformal anomalies on the defect worldvolume. The latter give riseto defect analogs of the c-theorem (a-th eorem) which establish the monotonicity of defect RG flows. With supersymm etry\, the defect conformal anomalies are related to the ‘t Hooft anomali es for certain U(1) R-symmetry in a simple way\, and can be determinednon- perturbatively from an algebraic procedure. In the talk I’ll mostly focus on surface defects to be concrete and comment on extensions and future dir ections towards the end.

DTSTART;TZID=Asia/Jerusalem:20210420T163000 DTEND;TZID=Asia/Jerusalem:20210420T173000 SEQUENCE:0 SUMMARY:Yifan Wang – SPECIAL TIME URL:https://phsites.technion.ac.il/strings/event/yifan-wang/ END:VEVENT BEGIN:VEVENT UID:15ghgfdcj2tqjhcn82h95ll4vr@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Hints of Gravitational Ergodicity

\nAbstract: R
ecent developments on black holes have shown that a

\nunitarity-compa
tible Page curve can be obtained from an

\nensemble-averaged semi-cla
ssical approximation. In this talk\, we

\nemphasize (1) that this pec
uliar manifestation of unitarity is not

\nspecific to black holes\, a
nd (2) that it can emerge from a single

\nrealization of an underlyin
g unitary theory. To make things explicit\,

\nwe consider a hard sphe
re gas leaking slowly from a small box into a

\nbigger box. We reprod
uce the unitarity-compatible Page curve of this

\nsystem\, semi-class
ically. Berry’s ensemble in which the eigenstates

\nlive\, plays a cr
ucial role. The computation has structural parallels

\nto replica wor
mholes\, relies crucially on ensemble averaging at each

\nepoch\, and
reveals the interplay between the multiple time-scales in

\nthe prob
lem. Working with the ensemble averaged state rather than the

\nentan
glement entropy\, we can also engineer an information “paradox”.

\nOu
r system provides a concrete example in which the ensemble

\nunderlyi
ng the semi-classical Page curve is an ergodic proxy for a

\ntime ave
rage\, and not an explicit average over many theories. The

\nquestion
s we address here are logically independent of the existence

\nof hor
izons\, so we expect that semi-classical gravity should also be

\nvie
wed in a similar light.

Title: Stringy ER=EPR.

\nAbstract: I will discuss a Lo rentzian interpretation of the FZZ duality as an equivalence between strin g perturbation theory about a two sided black hole and an entangled combin ation of disconnected microstates. The microstates involve a condensate of folded strings extending from a strong coupling region. Part of the machi nery involves string theory defined on Schwinger-Keldysh contours in targe t space\, and a novel contour of integration of the string moduli associat ed to angular quantization. I will further present an AdS3 uplift of this duality.

DTSTART;TZID=Asia/Jerusalem:20210504T170000 DTEND;TZID=Asia/Jerusalem:20210504T180000 SEQUENCE:0 SUMMARY:Daniel Jafferis – SPECIAL TIME URL:https://phsites.technion.ac.il/strings/event/daniel-jafferis-special-ti me/ END:VEVENT BEGIN:VEVENT UID:284nf21193odds02j0ojilos1r@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Progress in celestial holography

DTSTART;TZID=Asia/Jerusalem:20210511T160000 DTEND;TZID=Asia/Jerusalem:20210511T170000 SEQUENCE:0 SUMMARY:Andrew Strominger URL:https://phsites.technion.ac.il/strings/event/andrew-strominger/ END:VEVENT BEGIN:VEVENT UID:6arhvlcbr0v5k945cv0l9apkcv@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Deviations from factorization in SYK

\nAbstract : Recently\, there has been a revived interest in multi-boundary holograph ic systems and the contribution of Euclidean wormholes\, in particular in Jackiw-Teitelboim (JT) gravity. We consider Sachdev-Ye-Kitaev (SYK) as a m icroscopic model for such holographic systems. While in JT gravity the non -factorizing contributions come from geometric wormholes\, we get that in SYK there are much larger contributions. We give a diagrammatic descriptio n of all those leading contributions\, analogous to Feynman diagrams. The holographic behavior is particularly interesting for fixed SYK couplings d ue to factorization\, and we comment on that as well.

DTSTART;TZID=Asia/Jerusalem:20210518T160000 DTEND;TZID=Asia/Jerusalem:20210518T170000 SEQUENCE:0 SUMMARY:Vladimir Narovlansky URL:https://phsites.technion.ac.il/strings/event/vladimir-narovlansky/ END:VEVENT BEGIN:VEVENT UID:5n9ls6n5hr8om295r3sbrguqkj@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: 6d/5d dualities from Higgsing

\nAbstract: (Base
d on https://arxiv.org/abs/2103
.02799 with a slightly different title.)

5d supersymmetric gauge
theories are sometimes UV completed by 6d SCFTs. One such example is the
duality between the affine quiver gauge theory in 5d and 6d so-called “con
formal matter” theory labeled by a D or E type lie algebra. In this talk w
e will see that starting from this duality and performing nilpotent Higgsi
ng on both sides\, one can generate a huge set of 6d/5d dualities. The 6d
side often involves a twist along a compactification by a discrete symmetr
y. The 5d side does not always admit a gauge theory description\, but some
times does and involves an exceptional gauge group including G or F type o
r an exceptional (non-fundamental) matter content. As a byproduct\, we get
a web-based formalism to compute the Nekrasov partition function for some
of the exceptional 5d gauge theories.

Title: The Onset of Quantum Chaos

\nAbstract: We study the quantum version of the Lyapunov exponent in disordered theories. Gene rically the quantum Lyapunov exponent can only be computed in isolated CFT s\, and so not much is known about the way in which chaos grows as we defo rm the theory away from weak coupling. In this talk we describe families o f theories in which the disorder coupling is an exactly marginal deformati on\, allowing us to follow the Lyapunov exponent from weak to strong coupl ing. We find surprising behaviors in some cases\, including a discontinuou s transition into chaos\, which we compare to the expectation from classic al chaos. We also describe a new method allowing for computations in nontr ivial CFTs deformed by disorder.

DTSTART;TZID=Asia/Jerusalem:20210601T160000 DTEND;TZID=Asia/Jerusalem:20210601T170000 SEQUENCE:0 SUMMARY:Adar Sharon URL:https://phsites.technion.ac.il/strings/event/adar-sharon/ END:VEVENT BEGIN:VEVENT UID:2jc4bljpi06olerct5t338l41b@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: Large Charge Phases of CFTs

\nAbstract: CFTs wi th additional global symmetries often possess significant simplification i n the regime in which the charges associated with the global symmetries be come large. In this talk\, we review some recent developments in the subje ct of CFTs atlarge global charges. We present results that are based on tw o papers: The first\, (based on https://arxiv.org/abs/2102.12583)involves the study of constraints du e to spontaneously broken boosts and dilatation symmetries around heavy st ates\, and the implications of the symmetry breaking for the spectrum of C FTs. In the second\, we study boundary conformal field theories (BCFTs) wi tha global U(1) symmetry at the large charge regime.

DTSTART;TZID=Asia/Jerusalem:20210608T160000 DTEND;TZID=Asia/Jerusalem:20210608T170000 SEQUENCE:0 SUMMARY:Avia Raviv-Moshe URL:https://phsites.technion.ac.il/strings/event/avia-raviv-moshe-2/ END:VEVENT BEGIN:VEVENT UID:1qg3b8c8cmuv9d782m6mhf30rf@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:**Title: Complexity for CFTs in General Dimensions**

Abstract: In this talk\, I will discuss circuit complexity for conf ormal field theory states in arbitrary dimensions. The circuits start from a primary state and move along a unitary representation of the Lorentzian conformal group. I will consider different choices of distance functions and explain how they can be understood in terms of the geometry of coadjoi nt orbits of the conformal group. This analysis will highlight a connectio n between the coadjoint orbits of the conformal group and timelike geodesi cs in anti-de Sitter spacetimes\, with interesting implications regarding the holographic complexity proposals. This is based on a work with Nicolas Chagnet\, Jan de Boer and Claire Zukowski.

Title: Emergent symmetries in 3d and compactification from 5 d

\nAbstract: We study the phenomenon of symmetry enhancement in qua ntum field theories in three dimensions\, where the global symmetry of a m odel is larger in the IR than in the UV. We focus on supersymmetric theori es where the situation is more tractable\,and find an organizing principle for such enhancements in the form of compactifications of 5d theories on Riemann surfaces with flux in their global symmetries. We illustrate this by considering the compactification of the so-called 5d Seiberg SCFTs on t ori\,and obtain 3d theories with enhanced IR symmetries given by the 5d sy mmetry preserved by the chosen flux.

DTSTART;TZID=Asia/Jerusalem:20210706T160000 DTEND;TZID=Asia/Jerusalem:20210706T170000 SEQUENCE:0 SUMMARY:Orr Sela URL:https://phsites.technion.ac.il/strings/event/orr-sela-2/ END:VEVENT BEGIN:VEVENT UID:3ofpqh45bgr1ck28fotukfs9tn@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:Title: The structure of the initial conditions of the univer
se

\nAbstract: I will review what we know about the initial condition
s of the universe from observations. Then\, I will explain how they arise
within the framework of inflation\, and describe recent progress in classi
fying (or “bootstrapping”) the possible correlation functions between prim
ordial fluctuations. Finally\, time permitting\, I will touch upon work in
progress trying to apply the bootstrap philosophy to more general cosmolo
gies.

Title: Holography of Chronology Protection

\nAbstract:
After an introduction to time-machine spacetimes and simple models of them
\, I will discuss recent work with M. Tomasevic where we use holography to
study quantum effects when closed timelike curves (CTCs) are developed. W
e address the question of whether it is possible to send a signal across t
he chronology horizon\, passing into the region where CTCs are present. We
find that the self-interaction of quantum fields manages to banish the pa
ssage of field excitations into the non-chronal region. Going further\, we
compute the gravitational backreaction of the quantum fields\, and show t
hat the null chronology horizon turns into a strong\, spacelike curvature
singularity. This is one of the few controlled\, explicit examples where w
e can see quantum effects change a Cauchy horizon into a spacelike singula
rity.

Title: Mastering bounds on correlators

\nAbstract: We d
iscuss a new viewpoint onto the CFT landscape: bounds on values of CFT cor
relators. We show that such bounds can be obtained by constructing suitabl
e ‘master functionals’. We present both numerical results for 3d CFTs as w
ell as exact results for correlators on the line. The latter follow from c
rossing symmetric dispersion relations. We briefly discuss how these may b
e used to study the Regge and flat space limits of CFT correlators.

**Title: **Multi-trace correlators in the SYK model and N
on-geometric wormholes

**Abstract: **We consider the global flu
ctuations in the density of states of the SYK model\, which are much large
r than the standard RMT correlations. We provide a diagrammatic descriptio
n of their leading and subleading behavior. In either case\, the new set o
f correlations are not associated with (and are much larger than) the ones
given by topological wormholes\, and hint towards the dual of a single re
alization. In particular\, we suggest that incorporating them in the gravi
ty description requires the introduction of new\, lighter and lighter\, fi
elds in the bulk with fluctuating boundary couplings.

* Title: *Bootstrapping

** Abstract: **We study th
e

**Title: **Thermal Order in 3d

**Abstract: **
Our intuitive understanding of thermodynamics suggests that broken global
symmetries in the stable vacuum of a physical system\, get restored at hig
h temperatures. We construct a unitary\, UV-complete 3d QFT that instead e
xhibits a spontaneous breaking of continuous symmetries at all temperature
s. Our model consists of two copies of the long-range vector model\, with
O(m) and O(N−m) global symmetry groups\, perturbed by double-trace deforma
tions. The model exhibits a conformal manifold in the large rank limit\, t
hat is lifted by 1/N corrections. A certain class of IR fixed points are s
hown to undergo SSB at finite temperature\, with the pattern persisting to
all temperatures due to scale-invariance. We provide evidence that the mo
dels in question are unitary\, UV-complete\, as well as invariant under co
nformal symmetry. Our work adds to the growing list of models that display
persistent symmetry breaking (PSB)\, and discusses the necessary conditio
ns for the models to display such a behaviour.

**Title: **Conformal operators in SYK-like models and the
ir numerical effects

**Abstract: **Quantum mechanical models wi
th random interactions have an infinite number of bilinear operators\, the
scaling dimensions of which can be computed explicitly in the large N lim
it. The lowest dimension operators play an important role in thermodynamic
al properties of these models and define the behavior of various correlati
on functions in the infrared limit. In this talk I’ll show that some SYK-l
ike models have operators with unusual anomalous dimensions. I also demons
trate how they can be observed in numerical computations.

Based on works with Maria Tikhanovskaya\, Haoyu Guo and Subir Sachdev

\nhttps://arxiv.org/abs/2010.09742

https://arxiv.org/abs/20
12.14449

**Title:** Magnetic Quivers\, Phase Diagrams\, and Physic
s at Strongly Coupled Quantum Field Theories

**Abstract:** Quiv
er gauge theories experienced a breakthrough in activity through two impor
tant concepts\, called “magnetic quivers” and “Hasse (phase) diagrams”. Th
e first helps understanding the physics of strongly coupled gauge theories
and exotic theories with tensionless strings in 6d or with massless gauge
instants in 5d. The second gives an invaluable information about the phas
e structure of gauge theories\, in analogy with phases of water. The talk
will review these developments and explain their significance.

** Title: **Some aspects of line defects in d dimen
sions

** Abstract:** We consider renormalization group fl
ows on line defects in d dimensions. We define a “defect entropy” and argu
e that it decreases monotonically during RG flows. We apply this result to
line defects which appear in condensed matter and high energy physics\, i
ncluding magnetic (SPT) defects\, localized field defects\, and Wilson loo
ps. In some of these cases we make some new experimental predictions and i
n the case of Wilson lines we make some comparisons with localization and
holography.

**Title: **Automorphic Spectra and the Conformal Bootstra
p

**Abstract: **I will explain that the spectral geometry of hy
perbolic manifolds provides a remarkably faithful model of the modern conf
ormal bootstrap. In particular\, to each hyperbolic manifold\, one can ass
ociate a Hilbert space of local operators\, which is a unitary representat
ion of a conformal group. The scaling dimensions of the operators are rela
ted to the eigenvalues of the Laplacian on the manifold. The operators sat
isfy an operator product expansion. Finally\, one can define their correla
tion functions and derive bootstrap equations constraining the spectrum. A
s an application\, I will use conformal bootstrap techniques to derive upp
er bounds on the lowest positive eigenvalue of the Laplacian on closed hyp
erbolic surfaces and 2-orbifolds. In a number of notable cases\, the bound
s are nearly saturated by known surfaces and orbifolds. For instance\, the
bound on all genus-2 surfaces is λ1≤3.8388976481\, while the Bolza surfac
e has λ1≈3.838887258. The talk will be based on https://arxiv.org/abs/2111.12716\, which is joint wor
k with P. Kravchuk and S. Pal.

**Title: **Kramers-Wannier-like duality defects in (3+1)d
gauge theories

**Abstract:** I will introduce a class of non-i
nvertible topological defects in (3+1)d gauge theories whose fusion rules
are the higher-dimensional analogs of those of the Kramers-Wannier defect
in the (1+1)d critical Ising model. As in the lower-dimensional case\, the
presence of such non-invertible defects implies self-duality under a part
icular gauging of the discrete (higher-form) symmetries. I will illustrate
this by means of the example of SO(3) Yang-Mills (YM) at θ=π\, as well a
s SU(2)N=4 SYM at τ=i.

**Title: **O(N)\, Sp(2M)\, and OSp(1|2M) Models

**<
b>Abstract: **The upper critical dimension of the O(N) vector model is w
ell-known to be 4. In dimension 4-epsilon it is described by the Wilson-Fi
sher IR fixed point of the O(N) invariant scalar field theory with a small
positive quartic coupling. Above 4 dimensions\, this theory is non-renorm
alizable\, but in 4+epsilon dimensions it formally has a UV fixed point at
small negative coupling. For sufficiently large N\, its UV completion in
4

Replacing N of the scalar fields by 2M anticommuting scalars\, we find Sp(2M) invariant fixed points with imaginary coupling constants in dimensi on 6-epsilon. In the special case M=1 the symmetry is enhanced to OSp(1|2) \, and we argue that this theory describes the critical behavior of the ze ro-state Potts model\, or equivalently the random spanning forests. We end by discussing the OSp(1|4) invariant fixed point of the field theory with quintic interactions. Its upper critical dimension is 10/3\, and the 10/3 -epsilon expansion provides estimates of new critical exponents in d=3.

DTSTART;TZID=Asia/Jerusalem:20220308T160000 DTEND;TZID=Asia/Jerusalem:20220308T180000 SEQUENCE:0 SUMMARY:Igor Klebanov URL:https://phsites.technion.ac.il/strings/event/igor-klebanov/ END:VEVENT BEGIN:VEVENT UID:0np8c5h85b6n7n7sfsei7ciusa@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:**Title: **A new look at completeness and generali
zed symmetries**Abstract:** __We describ
e a proposal for completeness in QFT. It asserts that the physical observa
ble algebras produced by local degrees of freedom are the maximal ones com
patible with causality. We elaborate on equivalent statements to this idea
such as the non-existence of generalized symmetries and the uniqueness of
the net of algebras. For non-complete theories\, we explain how the exist
ence of generalized symmetries is unavoidable\, and further\, that they al
ways come in dual pairs with precisely the same size”\, measured by an alg
ebraic index. Entropic order/disorder parameters can be defined that sense
the dual pairs of generalized symmetries and satisfy a “certainty relatio
n”. We briefly describe applications to understand the density of charged
states and to holography.__

**Title: **Exactly Marginal Deformations and their Superg
ravity Duals**Abstract: **We study the space o
f supersymmetric AdS5 solutions of type IIB supergravity corresponding to
the conformal manifold of the dual N = 1 conformal field theories. We show
that the background geometry naturally encodes a generalised holomorphic
structure\, dual to the superpotential of the field theory\, with the exis
tence of the full solution following from a continuity argument. In partic
ular\, we address the long-standing problem of finding the gravity dual of
the generic N = 1 deformations of N = 4 super Yang-Mills: though we are n
ot able to give it in a fully explicit form\, we provide a proof-of-existe
nce of the supergravity solution. Using this formalism\, we derive a new r
esult for the Hilbert series of the deformed field theories.

**Title: **Complexity=Anything?

<
b>Abstract: Motivated by holographic complexity\, we examine a new cla
ss of gravitational observables in asymptotically AdS space associated wit
h codimension-one slices or with codimension-zero regions. We argue that
any of these observables is an equally viable candidate as the extremal vo
lume for a gravitational dual of complexity.

**Title: **Static Responses and Symmetries o
f Black Holes**Abstract: **__I will disc
uss features of the static responses of black holes in General Relativity.
In particular\, I will describe how black hole static responses are defin
ed in point particle effective theory and will explain how the vanishing o
f black hole Love numbers is a consequence of symmetries of the wave equat
ion in black hole backgrounds.__

**Title: **Line Operators in Chern-Simons-Matter Theories
and Bosonization in Three Dimensions**Abstract:
**We study Chern-Simons theories at large N with either bosonic or ferm
ionic matter in the fundamental representation. The most fundamental opera
tors in these theories are mesonic line operators\, the simplest example b
eing Wilson lines ending on fundamentals. We classify the conformal line o
perators along an arbitrary smooth path as well as the spectrum of conform
al dimensions and transverse spins of their boundary operators at finite ‘
t Hooft coupling. These line operators are shown to satisfy first-order ch
iral evolution equations\, in which a smooth variation of the path is give
n by a factorized product of two line operators. We argue that this equati
on together with the spectrum of boundary operators are sufficient to uniq
uely determine the expectation values of these operators. We demonstrate t
his by bootstrapping the two-point function of the displacement operator o
n a straight line. We show that the line operators in the theory of bosons
and the theory of fermions satisfy the same evolution equation and have t
he same spectrum of boundary operators.

**Title: **String stars in anti de Sitter space**<
br />****Abstract: **We study the ‘string star’ saddle\, also k
nown as the Horowitz-Polchinski solution\, in the middle of d+1 dimensiona
l thermal AdS space (d>2). We show that there’s a regime of temperatures i
n which the saddle is very similar to the flat space solution found by Hor
owitz and Polchinski. This saddle is hypothetically connected at lower tem
peratures to the small AdS black hole saddle. We also study\, numerically
and analytically\, how the solutions are changed due to the AdS geometry f
or higher temperatures. Specifically\, we describe how the solution joins
with the thermal gas phase\, and find the leading correction to the Hagedo
rn temperature due to the AdS curvature. Finally\, we study the thermodyna
mic instabilities of the solution and argue for a Gregory-Laflamme-like in
stability whenever extra dimensions are present at the AdS curvature scale
.

**Title: **Love and Naturalness

**Abstract: **
It has been known for a decade that black holes are the most rigid objects
in the universe: their tidal deformations (Love numbers) vanish identical
ly in general relativity in four dimensions. This has represented a natura
lness problem in the context of classical worldline effective field theory
. In my talk I will present a new symmetry of general relativity (Love sym
metry) that resolves this naturalness paradox. I will show that perturbati
ons of rotating black holes enjoy an SL(2\,R) symmetry in the suitable def
ined near zone approximation. This symmetry\, while approximate in general
\, in fact yields exact results about static tidal deformations. This symm
etry also implies that generic regular black hole perturbations form infin
ite-dimensional SL(2\,R) representations\, and in some special cases these
are highest weight representations. It is the structure of these highest
weight representations that forces the Love numbers to vanish. All other f
acts about Love numbers\, including their puzzling behaviour for higher di
mensional black holes\, also acquire an elegant explanation in terms of SL
(2\,R) representation theory.

**Title: **Fracton-Elasticity Duality and Dipole G
auge Symmetry**Abstract: **The generalization of par
ticle-vortex duality in 2+1 dimensions to elasticity introduces emergent
tensor gauge fields coupled to immobile charges\, identified as fractons.
We reformulate the duality in terms of ordinary gauge fields and derive mo
bility restrictions from gauge invariance.

**Title: **Large-Twist Limit for Any Charged Operator in
N=4 SYM

**Abstract: **The fishnet theory was obtained as a stro
ngly twisted\, weakly coupled limit of N=4 SYM. Though still non-trivial\,
it is much simpler than the original N=4 SYM theory. The appearance of in
tegrability is better understood (at least for the spectrum)\, and the hol
ographic dual was constructed from first principles. Both can be tied to t
he existence of an iterative structure for some of the correlators. Howeve
r\, the fishnet theory only contains two scalar fields\, and most of the o
perators of the original theory are now protected. In particular\, the gau
ge boson has completely decoupled. We argue that it is possible to devise
a double-scaling limit for any operator charged under the R-symmetry in N=
4 SYM. We consider several examples that were protected in the fishnet the
ory\, including operators containing the gauge boson. We show that the gen
eric situation involves some type of mixing with other operators. This wor
k is a first step towards a systematic expansion of N=4 SYM around the lar
ge-twist limit.

**Title**: Krylov complexity in quantum field th
eory and beyond**Abstra
ct**: Krylov complexity\, and dynamics in Krylov space m
ore generally\, have emerged recently as interesting probes of quantum dyn
amics. They were proposed as probes of quantum chaotic dynamics\, relating
the latter to growth of OTOC. We discuss Krylov dynamics in case of quant
um field theory\, and first notice that in the conformal case Krylov comp
lexity behaves universality with no regard to integrability or chaos of th
e underlying theory. We then discuss turning on mass\, placing the theory
on a space of finite size and/or introducing a UV cutoff. We notice that
each of these deformations is reflected in Lanczos coefficients and in the
behavior of Krylov complexity. We conclude with a conjecture strengthenin
g the Maldacena-Stanford-Shenker bound on OTOC\, outlining the role of UV
cutoff in the context of “universal operator growth hypothesis” and argue
behavior of Krylov complexity is qualitatively different from computation
al and holographic complexities.

**Title**: A simple model\, extracted using holo
graphy\, of a domain wall between a confining and a de-confining phases an
d its velocity.**Abstra
ct**: In the context of theories with a first order phas
e transition\, we propose a general covariant description of coexisting ph
ases separated by domain walls using an additional order parameter-like de
gree of freedom. In the case of a holographic dual to a confining and a de
-confing phases\, the re- sulting model extends hydrodynamics and has a si
mple formulation in terms of an action and a corresponding energy-momentum
tensor. The proposed description leads to simple analytic profiles of dom
ain walls\, including the surface tension density\, which agree nicely wit
h holographic numerical solu- tions. We show that for such systems\, the d
omain wall or bubble velocity can be expressed in a simple way in terms of
a perfect fluid hydrodynamic formula\, and thus in terms of the equation
of state. We test the predictions for various holographic domain walls.

Title: Mixed anomalies and generalized symmetries from 3d su perconformal indices

\nAbstract: Generalized symmetries and their mi xed anomalies have proved to be useful in providing non-trivial constraint s on the dynamics of QFTs. A natural question is whether these are related in any way to supersymmetric partition functions or indices\, which have also been used extensively to study SQFTs. In this talk\, we address this question in the context of 3d $mathcal{N} geq ≥3$ gauge theories using the superconformal index. In particular\, using the index we are able to dete ct mixed anomalies involving discrete 0-form symmetries\, and possibly a 1 -form symmetry. Gauging appropriate symmetries involved in such mixed anom alies\, we obtain various interesting theories with two-group structures o r non-invertible symmetries.

DTSTART;TZID=Asia/Jerusalem:20221129T103000 DTEND;TZID=Asia/Jerusalem:20221129T113000 SEQUENCE:0 SUMMARY:Matteo Sacchi (Oxford) URL:https://phsites.technion.ac.il/strings/event/matteo-sacchi-oxford/ END:VEVENT BEGIN:VEVENT UID:37l8tlu1s9q0nhtdfba8uk4tmb@google.com DTSTAMP:20230206T001016Z CATEGORIES;LANGUAGE=en-US:Neve Shalom CONTACT: DESCRIPTION:**Title**: Entanglement\, Chaos and Quantum Computation <
/p>\n

**Abstract**: We consider information spreading measures in ran
domly initialized variational quantum circuits and introduce entanglement
diagnostics for efficient computation. We study the correlation between qu
antum chaos diagnostics\, the circuit expressibility and the optimization
of the control parameters.

**Title**: Thermalization and Chaos in 1+1d QFTs

**Abstract**: Nonintegrable QFTs are expected to thermalize and exhibi
t emergence of hydrodynamics and chaos. In weakly coupled QFTs\, kinetic t
heory captures local thermalization\; such a versatile tool is absent away
from the perturbative regime. I will present analytical and numerical res
ults using nonperturbative methods to study thermalization at strong coupl
ing. I will show how requiring causality in the thermal state leads to str
ong analytic constraints on the thermodynamics and out-of-equilibrium prop
erties of any relativistic 1+1d QFT. I will then discuss Lightcone Conform
al Truncation (LCT) as a powerful numerical tool to study thermalization o
f QFTs. Applied to phi^{}^4 theory in 1+1d\, LCT reveals eigenstat
e thermalization and onset of random matrix universality at any nonzero co
upling. Finally\, I will discuss prospects for observing the emergence of
hydrodynamics in QFTs using Hamiltonian truncation.

**Title**: Holographic thermal correlators from supersymm
etric instantons.

**Abstract**: I will present an exact formula
for the thermal scalar two-point function in four-dimensional holographic
conformal field theories. The problem of finding it reduces to the analys
is of the wave equation on the AdS-Schwarzschild background. The two-point
function is computed from the connection coefficients of the Heun equatio
n\, which can be expressed in terms of the Nekrasov-Shatashvili partition
function of an SU(2) supersymmetric gauge theory with four fundamental hyp
ermultiplets. At large spin the instanton expansion of the thermal two-po
int function directly maps to the light-cone bootstrap analysis of the hea
vy-light four-point function. Using this connection\, we obtain the OPE da
ta of heavy-light double-twist operators directly from the Nekrasov-Shatas
hvili function.

**Title**: Quantization of the Zigzag Model

**Ab
stract**: The zigzag model is a relativistic integrable
N-body system describing the leading high-energy
semiclassical dynamics on the worldsheet of long confining strings in mass
ive adjoint two-dimensional QCD. I will discuss quantization of this model
. I will demonstrate that to achieve a consistent quantization of the mode
l it is necessary to account for the non-trivial geometry of phase space.
The resulting Poincaré invariant integrable quantum theory is a close cous
in of TT¯ deformed models.

__Title__: Classical Physics from Scattering Amplitudes\n

__Abstract__:

Recent years have seen great progress in our
understanding of the emergence of classical physics from quantum scatterin
g amplitudes\, in both gauge and gravitational theories. This program is m
otivated by several reasons. One of them is the idea that amplitudes manif
est certain physical properties that are not apparent otherwise. As an exa
mple of this idea\, I will show how the double copy property of scattering
amplitudes constrains the structure of the worldline EFT.

**Title**: Field theory defects through double scaling li
mits

**Abstract**: Defect operators in field theory are ver
y interesting for a number of reasons. Drawing inspiration from techniques
which have been very recently applied to uncover interesting properties o
f sectors of operators with large charge under a global symmetry\, we will
study defects in the Wilson-Fisher fixed point near d=4\,6 dimensions. Co
mbining with localization\, we will also use a double-scaling limit for ce
rtain Wilson loops in N=2 supersymmetric theories in 4d which allows to ma
ke exact statements at finite N.

\n**Abstract**: We will explain a study of four-point functions of scala
rs\, conserved currents\, and stress tensors in a conformal field theory\,
generated by a local contact term in the dual bulk description\, in two d
ifferent causal configurations. The first is the standard Regge configurat
ion in which the chaos bound applies. The second is the ‘causally scatteri
ng configuration’ in which the correlator develops a bulk point singularit
y. We find an expression for the coefficient of the bulk point singularity
in terms of the bulk S matrix of the dual bulk metric\, gauge fields\, an
d scalars\, and use it to determine the Regge scaling of the correlator on
the causally scattering sheet in terms of the Regge growth of this S matr
ix. We then demonstrate that the Regge scaling on this sheet is governed b
y the same power as in the standard Regge configuration\, and so is constr
ained by the chaos bound\, which turns out to be violated unless the bulk
flat space S matrix grows no faster than $s^2$ in the Regge limit. It foll
ows that in the context of the AdS/CFT correspondence\, the chaos bound ap
plied to the boundary field theory implies that the S matrices of the dual
bulk scalars\, gauge fields\, and gravitons obey the Classical Regge Grow
th (CRG) conjecture. We will also comment on recent progress in the same d
irection.
DTSTART;TZID=Asia/Jerusalem:20230110T120000
DTEND;TZID=Asia/Jerusalem:20230110T130000
SEQUENCE:0
SUMMARY:Suman Kundu (Weizmann)
URL:https://phsites.technion.ac.il/strings/event/suman-kundu-weizmann-2/
END:VEVENT
BEGIN:VEVENT
UID:4pdhtb7k6vp6ia7sa5ovj467b0@google.com
DTSTAMP:20230206T001016Z
CATEGORIES;LANGUAGE=en-US:Neve Shalom
CONTACT:
DESCRIPTION:

**Title**: Line defects in CFTs: from magnets to Wilson l
ines

**Abstract**: Line defects
describe one-dimensional probes of a quantum field theory. Physically inte
resting examples can be found in different systems\, ranging from condense
d matter physics to gauge theories. In this talk\, I will briefly review s
ome recent results on the renormalization group approach to l
ine defects in CFTs. I will then discuss some applications. In particular\
, I will discuss some interesting RG flows for Wilson lines in massless ga
uge theories\, and their relation with an instability to screening by char
ged fields.

**Title**: Global symmetry breaking and defect conformal
manifolds

**Abstract**:In the presence of exactly marginal oper
ators\, one can deform a conformal field theory to other such theories\, f
orming a space of theories living on what’s known as the conformal manifol
d. In a theory with conformal defects\, one may be able to retain the bulk
theory but transform the defect along what I’ll call the “defect conforma
l manifold”. This requires the existence of exactly marginal defect operat
ors. A simple setting where this happens is in the presence of a global sy
mmetry broken by the defect. The broken symmetry current gives rise to an
exactly marginal defect operator and a defect conformal manifold which is
the symmetry breaking coset. This simple observation lets us derive an exa
ct identity for integrated 4-point functions of the marginal defect operat
or which is highly nontrivial. We implement this in several models where t
he 4-point functions have been previously calculated.

**Title**: Effective theory of sub-maximal chaos

**Abstract**: I will present progress on formulating an effective descr
iption of the quantum butterfly effect at late times. After discussing max
imally chaotic examples\, I will turn to a particular limit of the SYK mod
el that displays sub-maximal chaos and discuss its effective description.
The final results can be matched in detail to stringy corrections to the g
ravitational eikonal S-matrix in holographic CFTs\, including a stringy Re
gge trajectory\, bulk to boundary propagators\, and multi-string effects t
hat are unexplored holographically.

**Title**: Chaos and Wormholes in the Sachdev-Ye-Ki
taev Model**Abstract**: The Sachdev-Ye-Kitaev (SYK) model is a solvable many-body theory
with a low-energy limit given

by the Schwartzian action foun
d for the boundary dynamics Jackiw-Teitelboim gravity. This model has grea
tly improved our understanding of many-body quantum chaos and black holes
.

In this talk\, after an introduction to the SYK model and random m
atrix theory\, we discuss the physics of the spectral form factor as a me
asure of quantum chaos. We will see that the long time behavior of the spe
ctral factor is closely related to wormhole solutions of two coupled SYK
models.