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BEGIN:VEVENT
SUMMARY:Dongmin Gang (APCTP)
DTSTART:20200420T080000Z
DTEND:20200420T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/1
DESCRIPTION:Title: Twisted indices in 3d-3d correspondence\nby Dongmi
n Gang (APCTP) as part of KIAS Strings Seminar\n\n\nAbstract\nI will talk
about 3d-3d relation for twisted indices on general Riemann surface and it
s applications to i) microstates counting of supersymmetric blackholes and
ii) mathematics of Reidermeister torsion on hyperbolic 3-manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yu Nakayama (Rikkyo University)
DTSTART:20200506T080000Z
DTEND:20200506T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/2
DESCRIPTION:Title: Supersymmetric CP-violating Weyl anomaly\nby Yu Na
kayama (Rikkyo University) as part of KIAS Strings Seminar\n\n\nAbstract\n
In CP-violating conformal field theories in four dimensions\, the Pontryag
in density can appear in the Weyl anomaly. The Pontryagin density in the W
eyl anomaly is consistent\, but it has a peculiar feature that the parent
three-point function of the energy-momentum tensor can violate CP only (se
mi-)locally.\n\nIn this talk\, I present our recent studies (with K. Nakag
awa) on the supersymmetric completion of the Pontryagin density in the Wey
l anomaly\, where the central charge c effectively becomes a complex numbe
r. I also introduce a recent debate over if a Weyl fermion in four-dimensi
ons may or may not have the Pontryagin density in the Weyl anomaly.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongsu Bak (KIAS & U. of Seoul)
DTSTART:20200511T080000Z
DTEND:20200511T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/3
DESCRIPTION:Title: Traversable wormholes and quantum gravity lab on the t
abletop\nby Dongsu Bak (KIAS & U. of Seoul) as part of KIAS Strings Se
minar\n\n\nAbstract\nIn this talk I will introduce the traversable wormhol
es which is related to quantum teleportation. I shall explain how the trav
ersable wormholes can be realized in the 2d JT gravity theory\, which is d
ual to two interacting SYK quantum systems. I will show how to confirm exp
erimentally the existence of the bulk wormhole with a simple set of operat
ors in the quantum mechanics side.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seok Kim (Seoul National University)
DTSTART:20200608T080000Z
DTEND:20200608T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/4
DESCRIPTION:Title: Microstates of AdS black holes\nby Seok Kim (Seoul
National University) as part of KIAS Strings Seminar\n\n\nAbstract\nI wil
l explain some solved/unsolved problems on the QFT dual microstates of BPS
black holes in AdS5 x S5. The problem reduces to understanding the local
BPS operators of the field theory at weak coupling. From the index\, one s
ees a fast growth of such states which accounts for the black hole entropy
. I concretely illustrate this fact (and other related ideas) by numerical
ly studying the index up to U(6) gauge groups. I will then explain a yet u
nsolved problem\, of explicitly constructing such operators in the cohomol
ogical setup.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vasilis Niarchos (University of Crete)
DTSTART:20200518T080000Z
DTEND:20200518T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/5
DESCRIPTION:Title: Matching type-B conformal anomalies\nby Vasilis Ni
archos (University of Crete) as part of KIAS Strings Seminar\n\n\nAbstract
\nI will revisit the standard type-A and type-B classification of\nconform
al anomalies in conformal field theory. There are general arguments\nthat
show that type-A conformal anomalies are very similar to chiral\nanomalies
and that they match in different phases of a theory. Such\narguments do n
ot generalize to type-B anomalies\, which are expected to\ndepend on the p
hase of the theory. Contrary to this general expectation\, I\nwill present
a new formal argument that can be used to prove the\nnon-perturbative mat
ching of a certain class of type-B conformal anomalies\nin 4d N=2 super-co
nformal field theories along the Higgs branch. In such\ncases the correspo
nding anomalies are non-trivial functions of exactly\nmarginal coupling co
nstants that can be computed using methods of\nsupersymmetric localisation
.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Li (Beijing\, Inst. Theor. Phys.)
DTSTART:20200615T080000Z
DTEND:20200615T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/6
DESCRIPTION:Title: Quiver Yangian from crystal melting\nby Wei Li (Be
ijing\, Inst. Theor. Phys.) as part of KIAS Strings Seminar\n\n\nAbstract\
nThe BPS counting of type IIA string theory on non-compact toric Calabi-Ya
u threefolds can be described by crystal melting. I will explain how to co
nstruct the BPS algebras for these theories by a “bootstrap" method\, wh
ere one solves for the algebra by demanding that it acts on the correspond
ing BPS crystal appropriately. The resulting algebras are quiver Yangians
Y(Q\,W) that are associated with the quiver and the superpotential of the
theory. Based on joint work with M. Yamazaki (arxiv: 2003.08909).\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlos Nunez (Swansea University)
DTSTART:20200525T080000Z
DTEND:20200525T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/7
DESCRIPTION:Title: Aspects of gauge-strings duality\nby Carlos Nunez
(Swansea University) as part of KIAS Strings Seminar\n\n\nAbstract\nI will
discuss aspects of super conformal field theories in diverse dimensions.
The focus will be on theories in four\, six and two dimensions. I will us
e a holographic perspective to present the topics. Some aspects of Integra
bility and RG flows away from the CFTs will be discussed. If time allows\,
the case of super conformal quantum mechanics will be addressed. This tal
k is based on papers I published in the last year.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Toldo (Ecole Polytechnique)
DTSTART:20200629T080000Z
DTEND:20200629T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/8
DESCRIPTION:Title: Spinning BPS black holes in AdS4 and their CFT duals\nby Chiara Toldo (Ecole Polytechnique) as part of KIAS Strings Seminar\
n\n\nAbstract\nIn this talk I will review recent progress on the microstat
e counting for rotating black holes in Anti-de Sitter (AdS) spacetime. I w
ill focus mostly on the gravitational part. I will review the known supers
ymmetric AdS solutions and I will describe how to construct two classes of
new BPS black holes in theories of four dimensional supergravity with upl
ift to M-theory. I will describe their physical properties including their
conserved charges and their entropy function. I will then review the stat
e-of-the-art concerning their microstate counting via supersymmetric local
ization.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nakwoo Kim (Kyung Hee University)
DTSTART:20200601T080000Z
DTEND:20200601T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/9
DESCRIPTION:Title: Updates on Precision Holography\nby Nakwoo Kim (Ky
ung Hee University) as part of KIAS Strings Seminar\n\n\nAbstract\nWe stud
y supergravity BPS equations which correspond to mass-deformation of some
representative AdS/CFT examples. The field theory of interest are N=4\, D=
4 super Yang-Mills\, the ABJM model in D=3\, and the Brandhuber-Oz fixed p
oint in D=5. For these gauge theories the free energy with mass terms for
matter multiplets is calculable in large-N limit using supersymmetric loca
lization technique. We suggest a perturbative method to solve the supergra
vity equations. For the dual of mass-deformed ABJM model we reproduce the
known exact solutions. For the mass-deformed Brandhuber-Oz theory our meth
od gives the holographic free energy in analytic form. For N=2* theory our
result is in good agreement with the localization result. (based on 1902.
00418)\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seyed Morteza Hosseini (IPMU)
DTSTART:20200706T080000Z
DTEND:20200706T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/10
DESCRIPTION:Title: Anomalies\, Black strings and the charged Cardy formu
la\nby Seyed Morteza Hosseini (IPMU) as part of KIAS Strings Seminar\n
\n\nAbstract\nWe derive the general anomaly polynomial for a class of two-
dimensional CFTs arising as twisted compactifications of a higher-dimensio
nal theory on compact manifolds\, including the contribution of its isomet
ries. We then use the result to perform a counting of microstates for dyon
ic rotating supersymmetric black strings in AdS(5) x S^5 and AdS(7) x S^4.
We explicitly construct these solutions by uplifting a class of four-dime
nsional rotating black holes. We provide a microscopic explanation of the
entropy of such black holes by using a charged version of the Cardy formul
a.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andy O'Bannon (U. of Southampton)
DTSTART:20200713T080000Z
DTEND:20200713T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/11
DESCRIPTION:Title: Central charges of two-dimensional boundaries and def
ects\nby Andy O'Bannon (U. of Southampton) as part of KIAS Strings Sem
inar\n\n\nAbstract\nIn a 2d conformal field theory (CFT) the central charg
e is defined from the Virasoro algebra. Crucially\, the central charge obe
ys the c-theorem\, a powerful\, universal\, non-perturbative constraint: t
he central charge must decrease under renormalization group flows. The cen
tral charge appears in many other places too\, such as stress-tensor two-p
oint functions\, thermal entropy\, entanglement entropy\, and so on. All o
f these indicate that the central charge counts CFT degrees of freedom. Ho
wever\, what happens with a 2d boundary of a 3d CFT\, or a 2d conformal de
fect in a higher-dimensional CFT? Generically in these cases no Virasoro a
lgebra is present. Can we still define a central charge? If so\, in what q
uantities does it appear? Can we prove a c-theorem? These questions may be
crucial for graphene with a boundary\, surface operators in gauge theory
CFTs\, and many other systems. In this talk I will summarize the state of
the art in this area\, including results for some example systems\, and op
en questions.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noppadol Mekareeya (Milano Bicocca)
DTSTART:20200810T080000Z
DTEND:20200810T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/12
DESCRIPTION:Title: Supersymmetry enhancement in the 3d S-fold theories\nby Noppadol Mekareeya (Milano Bicocca) as part of KIAS Strings Seminar
\n\n\nAbstract\nA local SL(2\,Z) transformation on the Type IIB brane conf
iguration gives rise to an interesting class of 3d superconformal field th
eories\, known as the S-fold SCFTs. One of the interesting features of suc
h a theory is that\, in general\, it does not admit a conventional Lagrang
ian description. Nevertheless\, it can be described by a quiver diagram wi
th a building block being an SCFT known as the T(U(N)) theory. In this tal
k\, we discuss various interesting properties of the S-fold theories\, inc
luding supersymmetry enhancement in the infrared as well as several intere
sting dualities. This talk will have a different emphasis than previous t
alks with the similar title and abstract.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sara Pasquetti (Milano Bicocca)
DTSTART:20200803T080000Z
DTEND:20200803T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/13
DESCRIPTION:Title: Free field correlators\, kernel functions and 4d mirr
or symmetry\nby Sara Pasquetti (Milano Bicocca) as part of KIAS String
s Seminar\n\n\nAbstract\nI will present a family of quiver 4d N=1 theories
which present an interesting pattern of IR symmetry enhancement and are r
elated by a new type of IR dualities which are very similar to 3d N=4 mir
ror dualities.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junya Yagi (Perimeter Institute)
DTSTART:20200817T080000Z
DTEND:20200817T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/14
DESCRIPTION:Title: Wilson-'t Hooft lines as transfer matrices\nby Ju
nya Yagi (Perimeter Institute) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nSupersymmetric gauge theories in four dimensions have various interrel
ated connections to quantum integrable systems. I will present a new corre
spondence which identifies Wilson-'t Hooft lines in N=2 circular quiver th
eories with transfer matrices of trigonometric systems. I will explain ho
w this correspondence is related to Costello's 4d Chern-Simons theory and
other similar correspondences. This is based on my joint work with Kazuno
bu Maruyoshi and Toshihiro Ota.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matti Jarvinen (APCTP)
DTSTART:20200928T080000Z
DTEND:20200928T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/15
DESCRIPTION:Title: Holographic Dense QCD and Neutron Stars\nby Matti
Jarvinen (APCTP) as part of KIAS Strings Seminar\n\n\nAbstract\nGauge/gra
vity duality can be used to study QCD at high densities and low temperatur
es where many other theoretical tools do not work and uncertainties are th
erefore large. I review recent progress on this topic\, including modeling
of both the nuclear and the quark matter phases\, which may appear in neu
tron star cores and neutron star mergers. Combining predictions from gauge
/gravity duality with state-of-the-art models of nuclear matter leads to a
family of feasible "hybrid" equations of state for cold QCD matter. I dis
cuss applications to analysis of isolated neutron stars\, to transport in
dense quark matter\, and to simulations of binary neutron star mergers.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lavneet Janagal (KIAS)
DTSTART:20201012T080000Z
DTEND:20201012T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/16
DESCRIPTION:Title: CANCELLED\nby Lavneet Janagal (KIAS) as part of K
IAS Strings Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthias Gaberdiel (ETH Zurich)
DTSTART:20201102T080000Z
DTEND:20201102T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/17
DESCRIPTION:Title: An exact AdS/CFT duality\nby Matthias Gaberdiel (
ETH Zurich) as part of KIAS Strings Seminar\n\n\nAbstract\nString theory o
n AdS3 x S3 x T4 with one unit of NS-NS flux is argued to be exactly dual
to the symmetric orbifold of T4 in the large N limit. The string theory ba
ckground can be described in terms of a solvable world-sheet theory. This
allows one to compute the complete single-string spacetime spectrum and th
ereby demonstrate that it agrees with that of the symmetric orbifold of T4
. Furthermore\, the structure of the symmetric orbifold correlators can be
reproduced from the world-sheet perspective.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert de Mello Koch (South China Normal U. and Witwatersrand U)
DTSTART:20201123T080000Z
DTEND:20201123T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/18
DESCRIPTION:Title: Why deep networks generalize\nby Robert de Mello
Koch (South China Normal U. and Witwatersrand U) as part of KIAS Strings S
eminar\n\n\nAbstract\nTraining a deep network involves applying an algorit
hm which fixes the parameters of the network. The performance of the train
ed deep network is evaluated by studying the trained network's performance
on unseen test data. The difference between how the network performs on t
he training data and on unseen data defines a generalization error. Networ
ks that perform as well on unseen data as they did on training data\, have
a small generalization error.\n\nWe have definite expectations for the si
ze of the generalization error\, based essentially on common sense. If the
training data set is much smaller than the number of parameters in the ne
twork\, training can fit any data perfectly\, so that errors and noise are
captured during training. Typical deeps network applications use deep net
works with hundreds of millions of parameters\, trained using data sets wi
th tens of thousands of parameters. Clearly then\, we are squarely in the
regime of large generalization errors. Remarkably however\, for typical de
ep learning applications\, the generalization error is small. This begs th
e question: why do deep nets generalize?\n\nIn this talk we develop parall
els between deep learning and the renormalization group to explain why dee
p networks generalize.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Herzog (King's College London)
DTSTART:20201109T053000Z
DTEND:20201109T063000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/19
DESCRIPTION:Title: Tractable models of boundary conformal field theory:
The case of O($N$) $\\phi^6$ theory in three dimensions\nby Christophe
r Herzog (King's College London) as part of KIAS Strings Seminar\n\n\nAbst
ract\nI present a study of O($N$) $\\phi^6$ theory in three dimensions wit
h a boundary.\nIn the large $N$ limit\, the theory is approximately confor
mal. Tuning an approximately marginal coupling drives the theory into diff
erent phases. This model further allows a calculation of the boundary cont
ribution to the anomaly in the trace of the stress tensor. Based on 2005.0
7863.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:R Loganayagam (ICTS-TIFR\, Bengaluru)
DTSTART:20201116T080000Z
DTEND:20201116T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/20
DESCRIPTION:Title: Interacting Hawking Radiation and Open QFTs\nby R
Loganayagam (ICTS-TIFR\, Bengaluru) as part of KIAS Strings Seminar\n\n\n
Abstract\nIn this talk\, I will outline some of the recent developments in
AdS/CFT which allow us to study open quantum field theories using hologra
phic methods. More precisely\, I will consider a quantum field theory (the
system) coupled to a holographic field theory at finite temperature (the
environment). The aim here is to integrate out the holographic environment
with an aim of obtaining an effective dynamics for the resulting open qua
ntum field theory. This is done using semiclassical gravitational Schwinge
r-Keldysh saddle geometries obtained by complexifying black hole spaceti
mes. In addition to shedding light on open quantum systems coupled to stro
ngly correlated thermal environments\, these results also capture both the
dissipative physics of black hole quasinormal modes\, as well as that of
the fluctuations encoded in outgoing Hawking quanta\, and interactions bet
ween them.\n\nThis talk will be based on https://arxiv.org/abs/2004.02888
as well as some upcoming work.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Wong (Fudan University)
DTSTART:20201130T080000Z
DTEND:20201130T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/21
DESCRIPTION:Title: Entanglement entropy and edge modes in topological st
ring theory\nby Gabriel Wong (Fudan University) as part of KIAS String
s Seminar\n\n\nAbstract\nThe Ryu Takayanagi formula identifies the area of
boundary anchored extremal surfaces in AdS with the entanglement entropy
of the boundary CFT. However the bulk microstate interpretation of the ext
remal area remains mysterious. Progress along this direction requires und
erstanding how to define entanglement entropy in the bulk closed string th
eory. As a toy model for AdS/CFT\, we study the entanglement entropy of
closed strings in the topological A model in the context of Gopakumar Vaf
a duality. We give a self consistent factorization of the closed string H
ilbert space which leads to string edge modes transforming under a q-defo
rmed surface symmetry group. Compatibility with this symmetry requires
a q-deformed definition of entanglement entropy. Using the topological
vertex formalism\, we define the Hartle Hawking state for the resolved co
nifold and compute its q-deformed entropy directly from the closed string
reduced density matrix. We find a match with a target space replica calcu
lation using the proposal of Susskind and Uglum. We then apply the Gopa
kumar Vafa duality to reproduce the closed string entropy from Chern Simo
ns theory using the un-deformed definition of entanglement entropy. Fin
ally we relate non local aspects of our factorization map to analogous phe
nomenon recently found in JT gravity.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony (Weizmann)
DTSTART:20201208T080000Z
DTEND:20201208T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/22
DESCRIPTION:Title: A derivation of AdS/CFT for vector models\nby Ofe
r Aharony (Weizmann) as part of KIAS Strings Seminar\n\n\nAbstract\nAfter
discussing what it means to derive the AdS/CFT correspondence\, I will des
cribe our attempts (in collaboration with Shai Chester and Erez Urbach\, 2
011.06328) to make this correspondence explicit in the simplest case of th
e O(N) vector model. We explicitly rewrite the path integral for the free
or critical O(N) (or U(N)) bosonic vector models in d space-time dimension
s as a path integral over fields (including massless high-spin fields) liv
ing on (d+1)-dimensional anti-de Sitter space. Inspired by de Mello Koch\,
Jevicki\, Suzuki and Yoon and earlier work\, we first rewrite the vector
models in terms of bi-local fields\, then expand these fields in eigenmode
s of the conformal group\, and finally map these eigenmodes to those of fi
elds on anti-de Sitter space. Our results provide an explicit (non-local)
action for a high-spin theory on anti-de Sitter space\, which is presumabl
y equivalent in the large N limit to Vasiliev's classical high-spin gravit
y theory (with some specific gauge-fixing to a fixed background)\, but whi
ch can be used also for loop computations. Our mapping is explicit within
the 1/N expansion\, but in principle can be extended also to finite N theo
ries\, where extra constraints on products of bulk fields need to be taken
into account.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takuya Okuda (University of Tokyo)
DTSTART:20201214T080000Z
DTEND:20201214T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/23
DESCRIPTION:Title: Janus interface entropy and Calabi's diastasis in fou
r-dimensional N=2 superconformal field theories\nby Takuya Okuda (Univ
ersity of Tokyo) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study t
he entropy associated with the Janus interface in a 4d N=2 superconformal
field theory. With the entropy defined as the interface contribution to an
entanglement entropy we show\, under mild assumptions\, that the Janus in
terface entropy is proportional to the geometric quantity called Calabi's
diastasis on the space of N=2 marginal couplings\, confirming an earlier c
onjecture by two of the authors and generalizing a similar result in two d
imensions. Our method is based on a CFT consideration that makes use of th
e Casini-Huerta-Myers conformal map from the flat space to the round spher
e.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi-Nan Wang (Oxford)
DTSTART:20210111T080000Z
DTEND:20210111T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/24
DESCRIPTION:Title: 5d and 4d SCFTs from canonical threefold singularitie
s\nby Yi-Nan Wang (Oxford) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nIn this talk\, I am going to investigate pairs of SCFTs associated to
a canonical threefold singularity\, which consists of: (1) a 5d N=1 SCFT f
rom M-theory (2) a 4d N=2 SCFT from IIB superstring theory. Interestingly\
, the Coulomb and Higgs branches of these theories can be studied by the r
esolution or deformation of the singularity\, and they are intertwined by
3d N=4 mirror symmetry. As the examples\, I am going to discuss Seiberg En
theories and also various theories associated to terminal singularities.
For the latter case\, they seem to describe either a free theory or the di
screte gauging of a free theory.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pietro Longhi (ETH Zurich)
DTSTART:20210201T080000Z
DTEND:20210201T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/25
DESCRIPTION:Title: (Beyond) BPS counting with Exponential Networks\n
by Pietro Longhi (ETH Zurich) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nThis talk is an introductory overview of the framework of exponential n
etworks\, its applications to counting BPS states in M theory compactifica
tions\, and related problems in enumerative geometry. \nAfter reviewing th
e relevant background and motivations\, I will present the key definitions
and show some applications. Time permitting\, I will discuss the relation
to quivers and wall-crossing invariants\, and a recent application to BPS
counting on the local Hirzebruch surface F_0.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tadashi Okazaki (Durham)
DTSTART:20210322T080000Z
DTEND:20210322T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/26
DESCRIPTION:Title: Operator Algebras in 3d N=4 gauge theories and their
applications\nby Tadashi Okazaki (Durham) as part of KIAS Strings Semi
nar\n\n\nAbstract\nThe algebras emerging from three-dimensional N=4 supers
ymmetric gauge theories allow for new approaches to quantum field theories
\, including computations of physical observables and rigorous formulatio
n of dualities. I will discuss the algebraic formulas of sphere partition
functions and correlation functions in terms of the twisted traces over th
e Verma modules of the quantized Coulomb and Higgs branch algebras based o
n my work 1911.11126 with Davide Gaiotto and stringent tests of dualities
of half-BPS boundary conditions via half-indices based on my works 1905.07
425\, 2010.13177.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leopoldo A. Pando Zayas (Michigan)
DTSTART:20210329T010000Z
DTEND:20210329T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/27
DESCRIPTION:Title: AdS BH entropy and the Kerr/CFT correspondence\nb
y Leopoldo A. Pando Zayas (Michigan) as part of KIAS Strings Seminar\n\n\n
Abstract\nThe Bekenstein-Hawking entropy of asymptotically Anti-de-Sitter
black holes in dimensions 4\, 5\, 6 and 7 has recently been given an stati
stical interpretation in the context of the AdS/CFT correspondence. The ex
planations provided make use of intricate knowledge of the dual field theo
ries in 3\, 4\, 5 and 6 dimensions. It is expected on accounts of the reno
rmalization flow paradigm that such a universal aspect as the Bekenstein-H
awking entropy might admit an explanation solely based on low-energy dynam
ics. We point that the Kerr/CFT correspondence realizes this expectation b
y providing a unified statistical interpretation for the entropy of all b
lack holes and discuss some of the implications of this state of affairs.\
n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dan Xie (Tsinghua)
DTSTART:20210315T080000Z
DTEND:20210315T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/28
DESCRIPTION:Title: Mixed hodge module and N=2 Coulomb branch solution\nby Dan Xie (Tsinghua) as part of KIAS Strings Seminar\n\n\nAbstract\nSe
iberg-Witten (SW) geometry has been the key to understand the Coulomb bran
ch of 4d N=2 theories. While many SW geometries have been found\, the unde
rstanding of Coulomb branch physics is still difficult due to following re
asons: a) The difficulty in extracting electric-magnetic charge and flavor
charge\; b) The difficulty in finding the physics at special vacua\; c) T
he difficulty of finding SW differential. We show that new mathematical s
tructure called mixed hodge module will help us solve above problems.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Diego Rodriguez Gomez (Oviedo)
DTSTART:20210308T080000Z
DTEND:20210308T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/29
DESCRIPTION:Title: Correlation functions in finite temperature CFT and b
lack hole singularities\nby Diego Rodriguez Gomez (Oviedo) as part of
KIAS Strings Seminar\n\n\nAbstract\nWe compute thermal 2-point correlation
functions in the black brane AdS5 background dual to 4d CFT’s at finite
temperature for operators of large scaling dimension. We find a formula t
hat matches the expected structure the OPE. It exhibits an exponentiation
property\, whose origin we explain. We also compute the first correction t
o the two-point function due to graviton emission\, which encodes the time
travel to the black hole singularity.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210323T053000Z
DTEND:20210323T070000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/30
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 2/3
\nby Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Se
minar\n\n\nAbstract\nD-instantons give non-perturbative contribution to st
ring theory amplitudes which can be computed using world-sheet techniques.
However the integrals that appear in this computation often have\ndiverge
nces from corners of the moduli spaces which cannot be tamed by the usual
procedure of analytic continuation. We show how using insights from string
field theory we can extract finite unambiguous results from these apparen
tly divergent integrals.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210322T053000Z
DTEND:20210322T070000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/31
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 1/3
\nby Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Se
minar\n\n\nAbstract\nD-instantons give non-perturbative contribution to st
ring theory amplitudes which can be computed using world-sheet techniques.
However the integrals that appear in this computation often have\ndiverge
nces from corners of the moduli spaces which cannot be tamed by the usual
procedure of analytic continuation. We show how using insights from string
field theory we can extract finite unambiguous results from these apparen
tly divergent integrals.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210324T053000Z
DTEND:20210324T070000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/32
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 3/3
\nby Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Se
minar\n\n\nAbstract\nD-instantons give non-perturbative contribution to st
ring theory amplitudes which can be computed using world-sheet techniques.
However the integrals that appear in this computation often have\ndiverge
nces from corners of the moduli spaces which cannot be tamed by the usual
procedure of analytic continuation. We show how using insights from string
field theory we can extract finite unambiguous results from these apparen
tly divergent integrals.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Per Kraus (UCLA)
DTSTART:20210412T020000Z
DTEND:20210412T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/33
DESCRIPTION:Title: 3d gravity in a box\nby Per Kraus (UCLA) as part
of KIAS Strings Seminar\n\n\nAbstract\nI will discuss recent work on the c
lassical and quantum formulation of pure 3d gravity with Dirichlet boundar
y conditions. Working in the covariant phase space formalism I will show h
ow to obtain the classical Poisson bracket algebra of observables in this
theory\, and then discuss quantization\, comparing low order results to ex
pectations based on TTbar deformed CFTs.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Prem Kumar (Swansea University)
DTSTART:20210510T080000Z
DTEND:20210510T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/34
DESCRIPTION:Title: Islands and Hawking radiation correlations of evapora
ting black holes\nby Prem Kumar (Swansea University) as part of KIAS S
trings Seminar\n\n\nAbstract\nWe consider the effect of shockwaves on the
entanglement structure of black holes. We examine the correlations in g
eneric subsets of the Hawking radiation emitted by evaporating black holes
following the shockwave insertion and find a zoo of competing island sadd
le points for the associated entanglement entropies. By computing the mutu
al information between early and late modes we establish long range correl
ations in the Hawking radiation.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Davide Cassani (Padova)
DTSTART:20210419T080000Z
DTEND:20210419T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/35
DESCRIPTION:Title: Effective field theory for the 4d N=1 index on the se
cond sheet\nby Davide Cassani (Padova) as part of KIAS Strings Seminar
\n\n\nAbstract\nThe counting of BPS states in four-dimensional N=1 theorie
s has attracted a lot of attention in recent years. A generating function
(with signs) for this counting problem is the supersymmetric index. This h
as branch cuts and hence several Cardy-like limits\, which are analogous t
o high-temperature limits. Particularly interesting is the second sheet\,
which has been shown to capture the microstates and phases of supersymmetr
ic black holes in AdS_5. The talk will present a manifestly supersymmetric
3d effective field theory approach to the Cardy-like limit on the second
sheet. Due to the interaction between massless and massive modes\, the 3d
theory flows to a trivially gapped vacuum. I will describe how\, up to exp
onentially small corrections\, the index is then completely characterized
by a universal\, finite series made of 3d local terms\, the supersymmetric
Casimir energy and a very simple logarithmic term. These will be determin
ed in part explicitly and in part conjecturally.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Jinwoo Kang (KAIST)
DTSTART:20210503T080000Z
DTEND:20210503T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/36
DESCRIPTION:Title: 6d (1\,0) SCFTs on a torus and Class S\nby Monica
Jinwoo Kang (KAIST) as part of KIAS Strings Seminar\n\n\nAbstract\nIt has
been a constant framework to utilize geometric analysis via compactificat
ion to study the strongly coupled regime of the lower-dimensional theories
via higher-dimensional theories. In particular\, I will present 4d N=2 su
perconformal field theories (of class S) from two 6d origins: (1\,0) theor
y on a torus and (2\,0) theory on a punctured Riemann surface. I will algo
rithmically describe how to get the 4d data from 6d (1\,0) SCFTs via F-the
ory with geometric-engineering and explain its physical significance.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeff Murugan (University of Cape Town)
DTSTART:20210426T080000Z
DTEND:20210426T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/37
DESCRIPTION:Title: A 4-dimensional duality web\nby Jeff Murugan (Uni
versity of Cape Town) as part of KIAS Strings Seminar\n\n\nAbstract\nI wil
l discuss the construction of a web of non-supersymmetric dualities in fou
r spacetime dimensions for theories with theta and Maxwell terms. Our cons
truction mirrors the recipe used in (2+1)-dimensions to demonstrate a simi
lar duality web for theories with Chern-Simons terms and points to a multi
-dimensional duality web that connects low energy theories in 4-\, 3- and
2-spacetime dimensions. Time permitting\, I will discuss some applications
to the physics of 3d topological insulators.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeong-Hyuck Park (Sogang University)
DTSTART:20210517T080000Z
DTEND:20210517T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/38
DESCRIPTION:Title: String Theory and Non-Riemannian Geometry\nby Jeo
ng-Hyuck Park (Sogang University) as part of KIAS Strings Seminar\n\n\nAbs
tract\nPostulating O(D\,D) symmetry as the fundamental principle\, General
Relativity including the Einstein equations can be unambiguously augmente
d to another pure gravity\, namely Double Field Theory. Formulated a prio
ri in terms of O(D\,D) covariant variables\, Double Field Theory and also
associated doubled worldsheet action not only geometrize the whole close
d string massless sector which is conventionally Riemannian\, but also des
cribe various non-Riemannian geometries as novel string backgrounds.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Benini (SISSA)
DTSTART:20210531T080000Z
DTEND:20210531T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/39
DESCRIPTION:Title: Superconformal Index and Gravitational Path Integral<
/a>\nby Francesco Benini (SISSA) as part of KIAS Strings Seminar\n\n\nAbst
ract\nAdS/CFT provides a consistent non-perturbative definition of quantum
\ngravity in asymptotically AdS spacetimes. Black holes should\ncorrespond
to ensembles of states in the boundary field theory. By\nperforming a car
eful analysis of the superconformal index of 4d N=4\nSU(N) Super-Yang-Mill
s theory\, with the help of a Bethe Ansatz type\nformula\, we are able to
exactly reproduce the Bekenstein-Hawking\nentropy of BPS black holes in Ad
S5 x S5. The large N limit exhibits\nmany competing contributions\, that w
e are able to identify with\ncomplex saddles of the (putative) gravitation
al path-integral. Along\nthe way we propose a necessary condition for comp
lex saddles to\ncontribute\, based on the size of their non-perturbative c
orrections.\nSuch a prescription exactly matches the field theory analysis
.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210622T080000Z
DTEND:20210622T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/40
DESCRIPTION:Title: [Date Changed] The String dual to Free $\\mathcal{N}=
4$ Super Yang-Mills theory\nby Rajesh Gopakumar (ICTS) as part of KIAS
Strings Seminar\n\n\nAbstract\nIn this talk we will discuss a proposal fo
r a worldsheet description for the ${\\rm AdS}_5\\times {\\rm S}^5$ string
theory dual to large $N$\, free $\\mathcal{N}=4$ super Yang-Mills in four
dimensions. The worldsheet theory is a natural generalisation of the twis
torial free sigma model for the tensionless string on ${\\rm AdS}_3\\times
{\\rm S}^3\\times \\mathbb{T}^4$. As in the case of ${\\rm AdS}_3$ the w
orldsheet theory contains spectrally flowed representations. We propose th
at in each such sector only a finite set of generalised zero modes (‘wed
ge modes’) are physical. We show that after imposing the appropriate res
idual gauge conditions\, this worldsheet description reproduces precisely
the spectrum of the planar gauge theory. The resulting physical picture is
a covariant version of the BMN light-cone string\, now with a finite numb
er of twistorial string bit constituents of an essentially topological wor
ldsheet.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seung-Joo Lee (IBS)
DTSTART:20210607T080000Z
DTEND:20210607T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/41
DESCRIPTION:Title: Tensionless Strings and the Swampland in Four Dimensi
ons\nby Seung-Joo Lee (IBS) as part of KIAS Strings Seminar\n\n\nAbstr
act\nThe aim of this talk is to report on recent progress towards understa
nding how string theory realizes general conjectures on the nature of quan
tum gravity\, focusing on four-dimensional theories with minimal supersymm
etry. Specifically we will address two famous conjectures: the Distance Co
njecture and the Weak Gravity Conjecture. The former claims that an infini
te tower of states should become light near the boundary of the moduli spa
ce. According to the Emergent String Conjecture\, this tower should corres
pond either to a Kaluza-Klein tower or to the excitation tower of a weakly
coupled critical string. We will first verify this within the framework o
f geometric F-theory compactifications\, by classifying infinite distance
limits in the Kahler moduli space and analyzing them including quantum cor
rections. We will then argue that the string tower at weak coupling provid
es a sublattice of particles fulfilling the Weak Gravity Conjecture\, at o
r away from the strict infinities.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julius Grimminger (Imperial College)
DTSTART:20210524T080000Z
DTEND:20210524T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/42
DESCRIPTION:Title: Branes\, Quivers\, and the affine Grassmannian\nb
y Julius Grimminger (Imperial College) as part of KIAS Strings Seminar\n\n
\nAbstract\nThe affine Grassmannian of a group G is an object from geometr
ic representation theory. We will see that it arises quite naturally when
studying gauge theories with 8 supercharges and the brane systems they liv
e on. We will begin by reviewing the notion of Hasse diagrams\, stratifica
tion and transverse slices for Coulomb branches of 3d N=4 quiver theories\
, and how this is captured by Kraft-Procesi transitions in the brane syste
m. We will then study the affine Grassmannian from this perspective\, star
ting with the simplest possible one where G=SL(2\,C). We will then general
ise to higher ranks and other classical groups. If there is enough time\,
exceptional groups will be addressed.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (University of Geneva)
DTSTART:20210621T080000Z
DTEND:20210621T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/43
DESCRIPTION:Title: Resurgence and BPS invariants\nby Jie Gu (Univers
ity of Geneva) as part of KIAS Strings Seminar\n\n\nAbstract\nAsymptotic s
eries are ubiquitous in physics. And the resurgence theory provides a pow
erful tool to study them. In particular the resurgence theory reveals tha
t different asymptotic series at different saddle points are related to ea
ch other by Stokes automorphisms characterised by Stokes constants. We arg
ue that the Stokes constants can be treated as new invariants of the theor
ies in question\, and in some non-trivial examples they are integers and t
hey can be interpreted as counting of BPS states. We support this stateme
nt with examples in Seiberg-Witten theory\, complex Chern-Simons theory\,
and topological string theory. The topological string -- spectral theory (
TS/ST) correspondence plays an important in the last example.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210608T050000Z
DTEND:20210608T063000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/44
DESCRIPTION:Title: [KIAS Lecture Series] Lecture 1: Deriving the $AdS_3/
CFT_2$ correspondence\nby Rajesh Gopakumar (ICTS) as part of KIAS Stri
ngs Seminar\n\n\nAbstract\nIn these lectures I will try to give an accessi
ble introduction to a program to derive the AdS/CFT duality starting from
the tensionless limit of the string theory. We will focus on the case of $
AdS_3/CFT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\ti
mes T^4$ has one unit of NS-NS flux and is dual to the free symmetric orbi
fold theory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in t
his limit is described by a twistorial free field sigma model. We will di
scuss how the perturbative string spectrum matches with those of the sing
le cycle operators on the orbifold. Then we go on to argue why correlation
functions of physical operators manifestly match with those of the orbifo
ld theory. This follows from a subtle but crucial property of localisation
of the string correlators on the moduli space. Time permitting I will als
o discuss some implications of the duality for the physics of black holes
in this background.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210609T050000Z
DTEND:20210609T063000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/45
DESCRIPTION:Title: [KIAS Lecture Series] Lecture 2: Deriving the $AdS_3/
CFT_2$ correspondence\nby Rajesh Gopakumar (ICTS) as part of KIAS Stri
ngs Seminar\n\n\nAbstract\nIn these lectures I will try to give an accessi
ble introduction to a program to derive the AdS/CFT duality starting from
the tensionless limit of the string theory. We will focus on the case of $
AdS_3/CFT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\ti
mes T^4$ has one unit of NS-NS flux and is dual to the free symmetric orbi
fold theory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in t
his limit is described by a twistorial free field sigma model. We will di
scuss how the perturbative string spectrum matches with those of the sing
le cycle operators on the orbifold. Then we go on to argue why correlation
functions of physical operators manifestly match with those of the orbifo
ld theory. This follows from a subtle but crucial property of localisation
of the string correlators on the moduli space. Time permitting I will als
o discuss some implications of the duality for the physics of black holes
in this background.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210610T050000Z
DTEND:20210610T063000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/46
DESCRIPTION:Title: [KIAS Lecture Series] Lecture 3: Deriving the $AdS_3/
CFT_2$ correspondence\nby Rajesh Gopakumar (ICTS) as part of KIAS Stri
ngs Seminar\n\n\nAbstract\nIn these lectures I will try to give an accessi
ble introduction to a program to derive the AdS/CFT duality starting from
the tensionless limit of the string theory. We will focus on the case of $
AdS_3/CFT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\ti
mes T^4$ has one unit of NS-NS flux and is dual to the free symmetric orbi
fold theory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in t
his limit is described by a twistorial free field sigma model. We will di
scuss how the perturbative string spectrum matches with those of the sing
le cycle operators on the orbifold. Then we go on to argue why correlation
functions of physical operators manifestly match with those of the orbifo
ld theory. This follows from a subtle but crucial property of localisation
of the string correlators on the moduli space. Time permitting I will als
o discuss some implications of the duality for the physics of black holes
in this background.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minsung Kim (POSTECH)
DTSTART:20210628T080000Z
DTEND:20210628T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/47
DESCRIPTION:Title: 5d/6d Wilson loops from blowups\nby Minsung Kim (
POSTECH) as part of KIAS Strings Seminar\n\n\nAbstract\nRecently\, BPS spe
ctra of large class of 5d and 6d supersymmetric quantum field theories are
computed via blowup equation. We generalize the blowup formula to calcula
te the partition function of 5d/6d field theories on Omega-background in p
resence of Wilson loop/Wilson surface operators. We test this approach by
calculating Wilson loop partition functions in various 5d/6d field theorie
s and comparing them with known results and expected dualities.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yutaka Yoshida (Tokyo Inst. of Technology)
DTSTART:20210712T080000Z
DTEND:20210712T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/48
DESCRIPTION:Title: Monopole bubbling and BPS 't Hooft operators in three
\, four and five dimensions\nby Yutaka Yoshida (Tokyo Inst. of Technol
ogy) as part of KIAS Strings Seminar\n\n\nAbstract\nWe evaluate the vacuum
expectation values of half-BPS 't Hooft operators in supersymmetric gauge
theories with eight supercharges in three\, four\, and five dimensions in
terms of supersymmetric localization. In localization formulas\, there ex
ist non-perturbative contributions from the moduli of Dirac monopoles scre
ened by 't Hooft-Polyakov monopoles\, called monopole bubbling effects (a.
k.a. monopole screening effects). By introducing orientifolds\, we general
ize the brane construction of monopole bubbling effects for SU(N) gauge th
eories to SO(N) and USp(N) gauge theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junho Hong (KU Leuven)
DTSTART:20210927T080000Z
DTEND:20210927T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/49
DESCRIPTION:Title: The topologically twisted index of N=4 SU(N) SYM theo
ry and a black hole Farey tail\nby Junho Hong (KU Leuven) as part of K
IAS Strings Seminar\n\n\nAbstract\nIn this talk\, we investigate the large
-N asymptotics of the topologically twisted index of N=4 SU(N) Super-Yang-
Mills (SYM) theory on T2×S2 and provide its holographic interpretation ba
sed on the black hole Farey tail. In the field theory side\, we use the Be
the-Ansatz (BA) formula\, which gives the twisted index of N=4 SYM theory
as a discrete sum over Bethe vacua\, to compute the large-N asymptotics of
the twisted index. In a dual N=2 gauged STU model\, we construct a family
of 5d extremal solutions uplifted from the 3d black hole Farey tail\, and
compute the regularized on-shell actions. The gravitational partition fun
ction given in terms of these regularized on-shell actions is then compare
d with a canonical partition function derived from the twisted index by th
e inverse Laplace transform\, in the large-N limit. This extends the previ
ous microstate counting of an AdS5 black string by the twisted index and t
hereby improves holographic understanding of the twisted index. Lastly\, w
e discuss future research directions.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Bertolini (SISSA\, Trieste)
DTSTART:20210915T080000Z
DTEND:20210915T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/50
DESCRIPTION:Title: The Octagon and the Non-Supersymmetric String Landsca
pe\nby Matteo Bertolini (SISSA\, Trieste) as part of KIAS Strings Semi
nar\n\n\nAbstract\nA long standing open question in the context of the gau
ge/gravity correspondence - more specifically in models of D-branes at Cal
abi-Yau singularities - regards the possibility of describing holographic
ally supersymmetric gauge theories that dynamically break supersymmetry in
stable vacua. In this talk I will present an orientifold of a Calabi-Ya
u singularity\, the Octagon\, which admits configurations of D-branes with
this property. This model represents the first such instance within the g
auge/gravity duality and may find interesting applications therein. I will
also explain to what extent this result might be relevant for the string
theory landscape and the swampland program.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Couzens (Utrecht University)
DTSTART:20210913T080000Z
DTEND:20210913T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/51
DESCRIPTION:Title: Black string near-horizons\, 2d quiver SCFTs and frac
tional branes\nby Christopher Couzens (Utrecht University) as part of
KIAS Strings Seminar\n\n\nAbstract\nWe will discuss a recently classified
class of (0\,4) AdS3 solutions in massless type IIA supergravity and their
dual CFTs. The solutions depend on solving a Laplace-like equation with a
flux source term. We will focus on a solution of this master equation whe
re the flux source term arises due to the presence of fractional branes pr
eserving conformality. We give a candidate dual quiver 2d CFT by studying
the brane construction and the quantized strings of the setup.\nThis talk
is based on recent work with Y. Lozano\, N. Petri\, and S. Vandoren.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenzo Di Pietro (Trieste University)
DTSTART:20211018T080000Z
DTEND:20211018T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/52
DESCRIPTION:Title: 5d gauge theories from the epsilon expansion\nby
Lorenzo Di Pietro (Trieste University) as part of KIAS Strings Seminar\n\n
\nAbstract\nThe seminar is based on: https://arxiv.org/abs/2107.00342. I w
ill discuss new evidence -from the 4+epsilon expansion- of the existence o
f interacting CFTs in 5d that provide UV completions of non-abelian gauge
theories. The method used is Padé-Borel resummation and extrapolation of
the five-loop pertubative results.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irene Valenzuela (Harvard University)
DTSTART:20211026T010000Z
DTEND:20211026T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/53
DESCRIPTION:Title: Non-Invertible Global Symmetries and Completeness of
the Spectrum in the Swampland Program\nby Irene Valenzuela (Harvard Un
iversity) as part of KIAS Strings Seminar\n\n\nAbstract\nIt is widely beli
eved that consistent theories of quantum gravity satisfy two basic kinemat
ic constraints: they are free from any global symmetry\, and they contain
a complete spectrum of gauge charges. For compact\, abelian gauge groups\,
completeness follows from the absence of a 1-form global symmetry. Howeve
r\, this correspondence breaks down for more general gauge groups\, where
the breaking of the 1-form symmetry is insufficient to guarantee a complet
e spectrum. We show that the correspondence may be restored by broadening
our notion of symmetry to include non-invertible topological operators\, a
nd prove that their absence is sufficient to guarantee a complete spectrum
for any compact\, possibly disconnected gauge group. In addition\, we pro
ve an analogous statement regarding the completeness of twist vortices: co
dimension-2 objects defined by a discrete holonomy around their worldvolum
e\, such as cosmic strings in four dimensions. I will also discuss how thi
s correspondence is modified in more general contexts\, including e.g. Che
rn-Simons terms.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero (Harvard University)
DTSTART:20211005T040000Z
DTEND:20211005T050000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/54
DESCRIPTION:Title: The anomaly that was not meant IIB\nby Miguel Mon
tero (Harvard University) as part of KIAS Strings Seminar\n\n\nAbstract\nT
ype IIB supergravity famously has a discrete duality group\, which is an e
xact symmetry of the full type IIB string theory. This symmetry has potent
ial quantum anomalies\, which could render the theory inconsistent. In thi
s talk I will describe how we computed these anomalies in recent work\, an
d show they are nonvanishing\, but remarkably\, they can be canceled by a
subtle modification of the IIB Chern-Simons term in what amounts to a new
variant of the Green-Schwarz mechanism. This only happens because of some
cancellations that depend on the precise details of the IIB supergravity s
pectrum. I will also describe alternative ways to cancel this anomaly\, pr
esenting variant versions of IIB string theory which have the same IIB sup
ergravity as the low-energy limit\, but which differ at the nonperturbativ
e level. These theories may or may not be in the Swampland.\n\n*Please not
e the unusual time of the seminar -comment added by organizer\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Murat Kologlu (Oxford)
DTSTART:20211101T080000Z
DTEND:20211101T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/55
DESCRIPTION:Title: Factorization in Quantum Gravity and Supersymmetry\nby Murat Kologlu (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract
\nOne of the lasting puzzles in quantum gravity is whether the holographic
description of a gravitational system is a single quantum mechanical theo
ry or the disorder average of many. In the latter case\, multiple copies o
f boundary observables do not factorize into a product\, but rather have h
igher moments. These correlations are interpreted in the bulk as due to ge
ometries involving spacetime wormholes which connect disjoint boundaries.
\n\nI will talk about the question of factorization and the role of wormho
les for supersymmetric observables\, specifically the supersymmetric index
. Working with the Euclidean gravitational path integral\, we will start w
ith a bulk prescription for computing the supersymmetric index\, which agr
ees with the usual boundary definition. Concretely\, we will focus on the
setting of charged black holes in asymptotically flat four-dimensional N=2
ungauged supergravity. In this case\, the gravitational index path integr
al has an infinite family of Kerr-Newman classical saddles with different
angular velocities. However\, fermionic zero-mode fluctuations annihilate
the contribution of each saddle except for a single BPS one which yields t
he expected value of the index. We will then turn to non-perturbative corr
ections involving spacetime wormholes\, and show that fermionic zero modes
are present for all such geometries\, making their contributions vanish.
This mechanism works for both single- and multi-boundary path integrals. I
n particular\, only disconnected geometries without wormholes contribute t
o the index path integral\, and the factorization puzzle that plagues the
black hole partition function is resolved for the supersymmetric index. We
will also classify all other single-centered geometries that yield non-pe
rturbative contributions to the gravitational index of each boundary. Fina
lly\, we will discuss implications and expectations for factorization and
the status of supersymmetric ensembles in AdS/CFT in further generality. T
alk based on [2107.09062] with Luca Iliesiu and Joaquin Turiaci.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin (Caltech)
DTSTART:20211012T010000Z
DTEND:20211012T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/56
DESCRIPTION:Title: Harmonic analysis of 2d CFT partition functions\n
by Nathan Benjamin (Caltech) as part of KIAS Strings Seminar\n\n\nAbstract
\nI will discuss applying the theory of harmonic analysis on the fundament
al domain of SL(2\,Z) to partition functions of 2d conformal field theorie
s. As an application I will decompose the partition function of c free bos
ons on a Narain lattice into eigenfunctions of the Laplacians of worldshee
t moduli space H/SL(2\,Z) and of target space moduli space O(c\,c\;Z)\\O(c
\,c\;R)/O(c)xO(c). This decomposition will make certain properties of Nara
in theories including their ensemble averages manifest. I will also discus
s applying harmonic analysis to a general irrational 2d CFT and its connec
tion with gravity in AdS3. I will prove that the primary spectrum of any 2
d CFT is fully determined by a certain subset of degeneracies. \n\n*Pleas
e be aware of the unusual date/time of the talk - comment added by organiz
er\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yosuke Imamura (Tokyo Inst. Tech.)
DTSTART:20211115T070000Z
DTEND:20211115T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/57
DESCRIPTION:Title: Finite-N superconformal index via the AdS/CFT corresp
ondence\nby Yosuke Imamura (Tokyo Inst. Tech.) as part of KIAS Strings
Seminar\n\n\nAbstract\nWe propose a prescription to calculate the superco
nformal index of the N=4 U(N) supersymmetric Yang-Mills theory\nwith finit
e N on the AdS side. The finite N corrections are included as contribution
s of D3-branes wrapped around\nthree-cycles in S5\, which are calculated a
s the index of the gauge theories realized on the wrapped branes.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Karch (U. Texas\, Austin)
DTSTART:20211210T010000Z
DTEND:20211210T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/59
DESCRIPTION:Title: Exploring continuum quantum field theories of fracton
order\nby Andreas Karch (U. Texas\, Austin) as part of KIAS Strings S
eminar\n\n\nAbstract\nRecently discovered solvable lattice models\, known
as fractons\, have\nforced us to rethink the very basic question of what a
quantum field\ntheory is. In order to describe the continuum limit of fra
cton lattice\nmodels\, novel quantum field theories had to be written down
that go\nbeyond what textbooks taught us\, exhibiting unusual features su
ch as\nsubsystem symmetries\, UV sensitivity of IR quantities\, and broken
\nrotation invariance. This talk will describe several explorations of the
\ninteresting new properties these unusual field theories exhibit.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Haowu Wang (IBS CGP\, Pohang)
DTSTART:20211116T070000Z
DTEND:20211116T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/60
DESCRIPTION:Title: Recent results on Jacobi forms of lattice index\n
by Haowu Wang (IBS CGP\, Pohang) as part of KIAS Strings Seminar\n\n\nAbst
ract\nIn 1985 Eichler and Zagier introduced the theory of Jacobi forms. Su
ch forms are holomorphic functions which are modular under SL(2\,Z) in the
first variable and quasi-periodic in the second variable. Later\, the Jac
obi form of lattice index was defined by replacing the second variable wit
h many variables associated with a positive-definite lattice. Jacobi forms
are an elegant intermediate between different types of modular forms and
have many applications in mathematics and physics. In this talk\, I will g
ive a brief introduction to this theory and present some recent results.
(1) In 1992 Wirthmüller proved that for any irreducible root system not o
f type E_8 the algebra of weak Jacobi forms invariant under the Weyl group
is a polynomial algebra. I will define the Jacobian of Jacobi forms and p
resent an automorphic proof of Wirthmüller's theorem. (2) Weyl invariant
weak Jacobi forms for the exceptional root system E_8 appear in E-string t
heory. I will prove several conjectures proposed by some physicists. This
gives a clear picture of the (non-free) algebra of such Jacobi forms. (3)
I will talk about the algebra of weak Jacobi forms for lattices of rank 2
. This talk is based on joint works with Brandon Williams and with Kaiwe
n Sun.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuji Hirono (APCTP)
DTSTART:20211206T070000Z
DTEND:20211206T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/61
DESCRIPTION:Title: Counting Nambu-Goldstone modes of higher-form global
symmetries\nby Yuji Hirono (APCTP) as part of KIAS Strings Seminar\n\n
\nAbstract\nWhen continuous symmetries are spontaneously broken\, there ap
pear\ngapless modes called Nambu-Goldstone (NG) modes. Due to their gaples
s\nnature\, they are important degrees of freedom at low energies.\nRecent
ly\, a generalized kind of symmetries\, called higher-form\nsymmetries\, h
ave been discussed\, whose charged objects are extended.\nThe analogue of
the NG theorem exists\, and photons can be regarded as\nNG modes for a spo
ntaneously broken higher-form symmetry.\nIn this talk\, I will discuss how
to count the number of NG modes\nassociated with spontaneously broken sym
metries that can include\nhigher-form ones [1]. I will give a formula for
the number of NG\nmodes\, which is also applicable for systems without Lor
entz\ninvariance.\n\nReference:\n[1] Y. Hidaka\, Y. Hirono\, R. Yokokura\,
Phys. Rev. Lett. 126\, 071601 (2021). [arXiv:2007.15901]\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hidenori Fukaya (Osaka University)
DTSTART:20211220T070000Z
DTEND:20211220T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/62
DESCRIPTION:Title: A physicist-friendly reformulation of the Atiyah-Pato
di-Singer index\nby Hidenori Fukaya (Osaka University) as part of KIAS
Strings Seminar\n\n\nAbstract\nThe Atiyah-Singer index theorem on a close
d manifold is well understood and appreciated in physics. On the other han
d\, the Atiyah-Patodi-Singer index\, which is an extension to a manifold w
ith boundary\, is physicist-unfriendly\, in that it is formulated with a n
onlocal boundary condition. Recently we proved that the same index as APS
is obtained from the domain-wall fermion Dirac operator. Our theorem indic
ates that the index can be expressed without any nonlocal conditions\, in
such a physicist-friendly way that application to the lattice gauge theory
is straightforward. The domain-wall fermion provides a natural mathematic
al foundation for understanding the bulk-edge correspondence of the anomal
y inflow.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (Southeastern University of China)
DTSTART:20211227T070000Z
DTEND:20211227T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/63
DESCRIPTION:Title: Resurgent structure in Chern-Simons theory\nby Ji
e Gu (Southeastern University of China) as part of KIAS Strings Seminar\n\
n\nAbstract\nThe resurgence theory is a powerful technique to analyse asym
ptotic series that arise in physics. We use the resurgence theory to study
the Chern-Simons theory with gauge group $\\mf{sl}_2$ on knot complement.
We compute the Stokes automorphisms that relate the asymptotic series in
the theory\, including the one from the trivial flat connection. We find s
urprising connection with BPS counting in 3d SCFT. We also construct a new
state integral from which all asymptotic series\, including the one for t
rivial connection\, can be derived.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yifan Wang (New York University)
DTSTART:20220125T010000Z
DTEND:20220125T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/64
DESCRIPTION:Title: Bootstrapping Boundaries and Branes\nby Yifan Wan
g (New York University) as part of KIAS Strings Seminar\n\n\nAbstract\nThe
study of conformal boundary conditions for two-dimensional conformal fiel
d theories (CFTs) has a long history\, ranging from the description of imp
urities in one-dimensional quantum chains to the formulation of D-branes i
n string theory. Nevertheless\, the landscape of conformal boundaries is l
argely unknown\, including in rational CFTs\, where the local operator dat
a is completely determined. We initiate a systematic bootstrap study of co
nformal boundaries in 2d CFTs by investigating the bootstrap equation that
arises from the open-closed consistency condition of the annulus partitio
n function with identical boundaries. We find that this deceivingly simple
bootstrap equation\, when combined with unitarity\, leads to surprisingly
strong constraints on admissible boundary states. In particular\, we deri
ve universal bounds on the tension (boundary entropy) of stable boundary c
onditions\, which provide a rigorous diagnostic for potential D-brane deca
ys. We also find unique solutions to the bootstrap problem of stable brane
s in a number of rational CFTs. Along the way\, we observe a curious conne
ction between the annulus bootstrap and the sphere packing problem\, which
is a natural extension of previous work on the modular bootstrap. We also
derive bounds on the boundary entropy at large central charge. These pote
ntially have implications for end-of-the-world branes in pure gravity on A
dS3.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuya Kusuki (Caltech)
DTSTART:20220222T010000Z
DTEND:20220222T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/65
DESCRIPTION:Title: Analytic Bootstrap in 2D Boundary Conformal Field The
ory\nby Yuya Kusuki (Caltech) as part of KIAS Strings Seminar\n\n\nAbs
tract\nRecently\, boundary conformal field theories (BCFTs) have attracted
much attention in the context of quantum gravity. This is because a BCFT
can be dual to gravity coupled to a heat bath CFT\, known as the island mo
del. On this background\, it would be interesting to explore the duality b
etween the boundary and the braneworld. \nHowever\, this seems to be a cha
llenging problem. The reason is because although there has been much study
of rational BCFTs\, there has been comparatively little study of irration
al BCFTs\, and irrational BCFTs are expected to be the boundary duals of t
he braneworlds. For this reason\, we explore properties of boundary ingred
ients: the boundary primary spectrum\, the boundary-boundary-boundary OPE
coefficients and the bulk-boundary OPE coefficients. For this purpose\, th
e conformal bootstrap is extremely useful. This is the first step in provi
ding an understanding of BCFTs in the context of braneworld holography by
using the conformal bootstrap. The techniques developed in this paper may
be useful for further investigation of irrational BCFTs.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul-Konstantin Oehlmann (Uppsala University)
DTSTART:20220221T080000Z
DTEND:20220221T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/66
DESCRIPTION:Title: Twisted Affine Algebras in F/M-theory\nby Paul-Ko
nstantin Oehlmann (Uppsala University) as part of KIAS Strings Seminar\n\n
\nAbstract\nIn this talk we discuss the geometry and physics of M/F-theory
compactifications on torus fibered Calabi-Yau threefolds that lack a sect
ion. Such geometries admit some striking novel features that are not prese
nt when the torus fiber admits a global section: \nThe absence of a sectio
n allows for generalized monodromies that act on the affine extension of A
DE fibers\, leading to twisted affine algebras in M-theory. We discuss the
effect of such foldings and their geometry in detail and track them throu
gh a chain of conifold transitions. This allows us to explain the twisted
affine algebras as the results of a 5D Higgsing\, where the representation
s have non-trivial charges under the KK U(1) which relates the theory to 6
D F-theory.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/66/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yiwen Pan (SYSU\, Guangzhou)
DTSTART:20220214T070000Z
DTEND:20220214T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/67
DESCRIPTION:Title: Exact Schur Index in Closed Form\nby Yiwen Pan (S
YSU\, Guangzhou) as part of KIAS Strings Seminar\n\n\nAbstract\nThe Schur
limit of the 4d N=2 superconformal index encodes rich information of the S
CFT\, and it also plays a central role in the SCFT/VOA correspondence as i
t coincides with the character of the associated VOA. There have been seve
ral ways to compute this quantity\, where it is written as a contour integ
ral\, or an infinite sum of group characters\, or simply a q-series. In th
is talk we propose for Lagrangian theories an elementary approach to furth
er compute the contour integral form of the index and the final result tak
es the form of a finite sum of products of the well-known Eisenstein serie
s. In particular\, we derive a compact formula for the flavored Schur inde
x of all class-S theories of type a_1\, and conjecture simple closed-form
for the unflavor index of all N=4 SYM theories with SU(N) gauge groups. We
also discuss some applications to the non-Lagrangian Schur index\, index
with non-local operators and modularity.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oleg Chalykh (University of Leeds)
DTSTART:20220523T080000Z
DTEND:20220523T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/68
DESCRIPTION:Title: Twisted Ruijsenaars models\nby Oleg Chalykh (Univ
ersity of Leeds) as part of KIAS Strings Seminar\n\n\nAbstract\nThe quantu
m Ruijsenaars model is a q-analogue of the Calogero—Moser model\, descri
bed by n commuting partial difference operators (quantum hamiltonians) h_1
\, …\, h_n. Its trigonometric variant is closely related to Macdonald po
lynomials and DAHAs. It turns out that for each natural number \\ell>1\, t
here exists an integrable system whose quantum hamiltonians look\, loosely
speaking\, as the \\ell-th powers of h_1\, …\, h_n. I will discuss seve
ral ways of arriving at this generalisation. In the elliptic case\, the de
formation parameter (“twisting”) is an arbitrary \\ell-torsion point c
on the underlying elliptic curve\; when c=0 one gets precisely the \\ell-
th powers of h_1\, …\, h_n. The construction works for all root systems\
, including the Van Diejen's system (BC_n case) - the existence of such a
twisted version of the Van Diejen's system was previously conjectured by E
ric Rains.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theodore D. Brennan (U. Chicago)
DTSTART:20220315T010000Z
DTEND:20220315T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/69
DESCRIPTION:Title: Callan Rubakov Effect and Higher Charge Monopoles
\nby Theodore D. Brennan (U. Chicago) as part of KIAS Strings Seminar\n\n\
nAbstract\nIn this talk we will discuss the interaction between magnetic m
onopoles and massless fermions. In the 1980's Callan and Rubakov showed th
at in the simplest example and that fermion-monopole interactions catalyze
proton decay in GUT completions of the standard model. Here we will expla
in how fermions in general representations interact with general spherical
ly symmetric monopoles and classify the types of symmetries that are broke
n: global symmetries with ABJ-type anomalies.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Du Pei (Harvard CMSA)
DTSTART:20220329T010000Z
DTEND:20220329T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/70
DESCRIPTION:Title: Holomorphic CFTs and topological modular forms\nb
y Du Pei (Harvard CMSA) as part of KIAS Strings Seminar\n\n\nAbstract\nThe
theory of topological modular forms leads to many interesting constraints
and predictions for two-dimensional quantum field theories. In this talk\
, I will show that a conjecture by Segal\, Stolz and Teichner requires the
constant term of the partition function of a bosonic holomorphic CFTs to
be divisible by specific integers determined by the central charge. We ver
ify this constraint in large classes of physical examples\, and rule out t
he existence of an infinite set of "extremal CFTs"\, including those with
central charges c = 48\, 72\, 96 and 120.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sung-Soo Kim (UESTC\, Chengdu)
DTSTART:20220328T070000Z
DTEND:20220328T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/71
DESCRIPTION:Title: 6d Seiberg-Witten curves from 5-brane webs\nby Su
ng-Soo Kim (UESTC\, Chengdu) as part of KIAS Strings Seminar\n\n\nAbstract
\nIn this talk\, we discuss the construction of the Seiberg-Witten (SW) cu
rves based on Type IIB 5-brane webs. After reviewing the construction for
SW curves for 5d supersymmetric gauge theories\, we discuss how to general
ize it to 6d superconformal theories which can be realized on a 5-brane we
bs with periodic direction. In particular\, we construct the SW curve for
6d E-string theory using a 5-brane web with two O5-planes. In fact\, the E
-string SW curve was first constructed by Eguchi and Sakai which is rather
complicated. Our expression is\, however\, much simpler than the Eguchi a
nd Sakai’s one. We discuss equivalence between our curve and the Eguchi
and Sakai. Finally we further generalize our construction of the SW curves
to 6d little string theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hee-Joong Chung (Jeju National University)
DTSTART:20220224T070000Z
DTEND:20220224T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/72
DESCRIPTION:Title: BPS Invariants for a Knot in Seifert Manifolds\nb
y Hee-Joong Chung (Jeju National University) as part of KIAS Strings Semin
ar\n\n\nAbstract\nIn this talk\, we discuss homological blocks for a knot
in Seifert manifolds obtained from the Chern-Simons partition function wit
h a Wilson loop operator when the gauge group is SU(N). From the expectati
on value of the Wilson loop operator\, we calculate the homological blocks
by analytically continuing the Chern-Simons level with a given representa
tion. We also obtain homological blocks with the analytically continued le
vel and representation for a knot in the Seifert integer homology spheres.
\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kanghoon Lee (APCTP)
DTSTART:20220314T070000Z
DTEND:20220314T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/73
DESCRIPTION:Title: QFT from Recursions\nby Kanghoon Lee (APCTP) as p
art of KIAS Strings Seminar\n\n\nAbstract\nWe discuss off-shell recursion
relations for arbitrary loop-level scattering amplitudes beyond the conven
tional tree-level recursion relations. We define a quantum perturbiner exp
ansion that includes loop corrections from the quantum effective action fo
rmalism. Instead of using the classical equations of motion in the conven
tional perturbiner method\, we exploit the Dyson–Schwinger equation to d
erive the quantum off-shell recursion relation. Furthermore\, we construct
the recursions for computing loop-level correlation functions by replacin
g the choice of the external source.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Byoungjoon Ahn (GIST)
DTSTART:20220418T070000Z
DTEND:20220418T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/74
DESCRIPTION:Title: Holographic teleportation and traversable wormholes\nby Byoungjoon Ahn (GIST) as part of KIAS Strings Seminar\n\n\nAbstract
\nIn general\, the non-traversability of wormholes is a consequence of the
Average Null Energy Condition (ANEC). Gao\, Jafferis and Wall (GJW) reali
zed that\, by coupling the two boundary theories with a relevant perturbat
ion\, ANEC can be violated\, and the wormhole can be made traversable in a
two-sided BTZ black hole. We generalize the GJW results to higher-dimensi
onal traversable wormholes in the context of Rindler-AdS/CFT and show that
the same result can be obtained using the eikonal approximation. We also
introduce the double trace operator with U(1) conserved current operators
in the AdS-Schwarzschild black hole and study the effects of conservation
laws on traversable wormholes. We discuss how the wormhole opening depends
on the charge diffusion constant and how this affects the amount of infor
mation that can be sent through the wormhole.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Couzens (Kyung-Hee University)
DTSTART:20220411T070000Z
DTEND:20220411T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/75
DESCRIPTION:Title: Multi charge Discs and Spindles\nby Christopher C
ouzens (Kyung-Hee University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nIn this talk I will discuss recent advances of the last year in underst
anding black holes with disc or spindle horizons. The metrics on these dis
cs and spindles have non-constant curvature with orbifold singularities\,
(or worse than orbifold singularities) and they evade the uniformization t
heorems. \nDespite the singularities one obtains well-defined string/M-the
ory solutions and in certain cases all singularities in the uplifted theor
y are resolved. We will conclude with some comments on dual field theories
.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seung-Joo Lee (IBS-CTPU)
DTSTART:20220530T070000Z
DTEND:20220530T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/76
DESCRIPTION:Title: The fate of not being minimal\nby Seung-Joo Lee (
IBS-CTPU) as part of KIAS Strings Seminar\n\n\nAbstract\nIn the context of
eight-dimensional F-theory\, we will discuss the physical interpretation
of singular fibers with vanishing orders (4\,6\,12) or beyond\, which are
known as non-minimal fibers. While minimal fibers in codimension-one loci
of the base lead to vector fields valued in a Lie algebra\, non-minimal fi
bers do not acquire such a clean interpretation and hence have typically b
een discarded in the literature. In this talk we will clarify the fate of
non-minimal fibers in the language of the effective physics and will put i
t also into a more general context of the relevant swampland conjectures f
or quantum gravity.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuya Tanizaki (Kyoto YITP)
DTSTART:20220404T070000Z
DTEND:20220404T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/77
DESCRIPTION:Title: Semiclassical description of confinement via center v
ortices and anomaly-preserving T^2 compactifications\nby Yuya Tanizaki
(Kyoto YITP) as part of KIAS Strings Seminar\n\n\nAbstract\nConfinement o
f 4d gauge theories is usually the strong-coupling problem\, and it is a d
ifficult task to understand even its qualitative features. We are trying t
o develop its semiclassical understanding based on the idea of volume inde
pendence or adiabatic continuity. We conjecture that the strong-coupling r
egime of many 4d gauge theories is continuously connected to the weak-coup
ling theories on small R2xT2 with the nontrivial ‘t Hooft flux. We expli
citly confirm the fractional theta periodicity for pure YM and chiral Lagr
angian for QCD can be derived in this small T2 regime\, which partly justi
fies our conjecture. We also uncover why this is possible in view of anoma
ly-preservation of this compactification.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Del Zotto (Uppsala University)
DTSTART:20220509T080000Z
DTEND:20220509T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/78
DESCRIPTION:Title: Back to Heterotic Instantons on ALE spaces: F-theory\
, 2-groups\, and T-duality\nby Michele Del Zotto (Uppsala University)
as part of KIAS Strings Seminar\n\n\nAbstract\nThe matching of the 2-group
structure constants for T-dual pairs of little string theories is a strin
gent constraint. In this talk\, I will discuss an application to the probl
em of charting the T-dualities of Heterotic ALE instantons.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junho Hong (KU Leuven)
DTSTART:20220620T070000Z
DTEND:20220620T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/79
DESCRIPTION:Title: Large N Topologically Twisted Indices\, Holography\,
and Black Holes\nby Junho Hong (KU Leuven) as part of KIAS Strings Sem
inar\n\n\nAbstract\nIn this talk\, I will present a simple closed form exp
ression for the topologically twisted index of the ABJM theory as a functi
on of the magnetic fluxes and complexified electric chemical potentials va
lid at fixed k and to all orders in the large N expansion. This in turn le
ads to analytic expressions for the topologically twisted index at fixed g
enus in the 't Hooft limit\, to all orders in the large λ=N/k expansion.
These results have important implications for holography and the microscop
ic entropy counting of supersymmetric static AdS4 black holes. I will also
briefly discuss generalizations to other SCFTs arising from M2-branes.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ying-Hsuan Lin (Harvard)
DTSTART:20220613T070000Z
DTEND:20220613T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/80
DESCRIPTION:Title: Topological modular forms and Monstrous Moonshine
\nby Ying-Hsuan Lin (Harvard) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nWe use the theory of topological modular forms to constrain bosonic hol
omorphic CFTs\, which can be viewed as (0\,1) SCFTs with a trivial right-m
oving supersymmetric sector. A conjecture by Segal\, Stolz and Teichner re
quires the constant term of the partition function to be divisible by spec
ific integers determined by the central charge. We verify this constraint
in large classes of physical examples\, and rule out the existence of an i
nfinite set of extremal CFTs\, including those with central charges c=48\,
72\,96 and 120. Applying the constraint to orbifolds of multiple copies of
the Monster CFT\, and aided by Borcherds' generalized denominator formula
\, we are further led to number-theoretic observations on the Fourier coef
ficients of the McKay-Thompson series.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20220517T010000Z
DTEND:20220517T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/81
DESCRIPTION:Title: D-instanton superpotential in string theory\nby M
anki Kim (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\nD-instantons
generate non-perturbative corrections to string theory amplitudes. These
corrections are of particular importance because they encode non-perturbat
ive effects in string theory and play a prominent role in moduli stabiliza
tion. In this talk\, I will focus on D-instanton contributions\, more prec
isely D(-1) and ED3 instanton contributions\, to the superpotential of low
energy effective theory of string compactification. Computing such contri
butions is challenging\, because of the IR divergence due to zero modes of
the D-instanton and the fact that some instanton contributions are expect
ed to be generated in the presence of non-trivial RR and NSNS fluxes. To c
ompute the D-instanton superpotential\, one must compute the one-loop dete
rminant around the saddle point. Due to the fact that these saddle point s
olutions have zero modes\, the overall normalization of the superpotential
contribution is ambiguous within the worldsheet formalism. I will discuss
how one can use string field theory to regularize the amplitude to obtain
an unambiguous answer. In part two of the talk\, I will explain that the
D(-1)-instanton contribution is expected to be generated in a non-trivial
flux background\, hence the direct computation of such effects is currentl
y out of reach. I will show how one can use F-theory to compute the D(-1)-
instanton superpotential and argue that in the global Sen-limit the D(-1)-
instanton superpotential is absent.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Hong Lee (KAIST)
DTSTART:20220425T070000Z
DTEND:20220425T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/82
DESCRIPTION:Title: Higgs\, Coulomb and Hall-Littlewood\nby Ki-Hong L
ee (KAIST) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study the Hig
gs branch of class-S theories with twist lines\, by studying their 3d redu
ction and corresponding mirror dual theories (or magnetic quivers).\nWe fi
nd many of them having the entire 'Higgs branch' fibered over an unbroken
Coulomb branch direction. By this\, we point out the difference between th
e Higgs sector and the Hall-Littlewood sector\, which have been long belie
ved to be identical for genus 0 theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/82/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenbin Yang (Stanford)
DTSTART:20220531T020000Z
DTEND:20220531T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/83
DESCRIPTION:Title: Firewalls from Wormholes\nby Zhenbin Yang (Stanfo
rd) as part of KIAS Strings Seminar\n\n\nAbstract\nI will address an ongoi
ng project with Douglas Stanford addressing the typical state firewall par
adox\, which is one of the remaining paradox regarding the interior of bla
ck holes.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thorsten Schimannek (Sorbonne Université)
DTSTART:20220810T070000Z
DTEND:20220810T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/84
DESCRIPTION:Title: Counting BPS states with discrete charges in M-theory
\nby Thorsten Schimannek (Sorbonne Université) as part of KIAS String
s Seminar\n\n\nAbstract\nDiscrete gauge symmetries can arise in M-theory o
n Calabi-Yau threefolds with terminal singularities. I will argue that the
Gopakumar-Vafa invariants are encoded in partition functions associated t
o different values of a discrete flat but topologically non-trivial B-fiel
d that stabilizes the singularities. Locally\, the effect of the B-field c
an be interpreted as replacing each node by a non-commutative conifold. Th
is picture allows us to derive closed expressions for the constant map con
tributions to the topological string partition functions on non-commutativ
e crepant resolutions.\nThe main example in this talk will be singular tor
us fibered Calabi-Yau 3-folds that share the same Jacobian fibrations as s
mooth genus one fibered Calabi-Yaus. Somewhat miraculously\, all of the re
levant partition functions can then be recovered at newly discovered non-c
ommutative large volume limits in the stringy Kähler moduli spaces of a r
ich network of interconnected torus fibrations. This makes it possible to
extract the Gopakumar-Vafa invariants associated to discrete charged BPS s
tates in M-theory on singular Calabi-Yau threefolds.\nIf time permits\, I
will also comment on the F-theory interpretation in terms of twisted ellip
tic genera and use this to deduce the 6d discrete 't Hooft anomaly.\nThe t
alk is mainly based on 2108.09311 by the speaker and on work in progress w
ith Albrecht Klemm\, Sheldon Katz and Eric Sharpe.\nThe application to ano
malies is work in progress with Markus Dierigl and Paul Oehlmann.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Institute)
DTSTART:20220704T070000Z
DTEND:20220704T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/85
DESCRIPTION:Title: Supersymmetry and trace formulas\nby Changha Choi
(Perimeter Institute) as part of KIAS Strings Seminar\n\n\nAbstract\nIn t
he context of supersymmetric quantum mechanics\, we present a new class of
supersymmetric localization principles with an application to trace formu
las in mathematics describing thermal partition function. Contrary to the
standard supersymmetric localization\, this new principle deals with a sup
ertrace of non-supersymmetric observables. Moreover\, the invariant deform
ation on the path integral side localizes onto non-trivial periodic orbits
. We illustrate the principle by deriving bosonic trace formulas on compac
t Lie groups.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/85/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sungwoo Hong (University of Chicago\, Argonne National Lab)
DTSTART:20220630T030000Z
DTEND:20220630T040000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/86
DESCRIPTION:Title: New Anomalies\, TQFTs\, and Confinement in Bosonic Ch
iral Gauge Theories\nby Sungwoo Hong (University of Chicago\, Argonne
National Lab) as part of KIAS Strings Seminar\n\n\nAbstract\nIn this talk\
, I will introduce a class of four dimensional chiral gauge theories which
is purely bosonic. By "bosonic" I mean that these theories do not admit a
ny fermionic gauge invariant operators. Then I discuss possibly the most c
omprehensive set of `t Hooft anomalies that the theory possesses. For this
\, I will discuss general background \nfields that can be consistently act
ivated. The final outcome of this is a combination of centers of color\, n
on-abelian flavor symmetry\, and U(1) symmetry of the theory\, which we ca
ll CFU backgrounds. Next\, I will discuss anomaly matching assuming confin
ement as the IR phase. I will show that a combination of the following fac
ts imposes serious \nchallenges for the anomaly matching (hence confinemen
t as a possible IR phase):\n(1) Theory is bosonic\, so no possible composi
te fermions to match continuous anomalies.\n(2) Theorems regarding existen
ce/absence of "symmetry preserving TQFTs"\n(3) Possible vacuum operators a
nd associated breaking of flavor symmetries.\n(4) Dimensional analysis and
RG flow.\n\nFocusing on an example of SU(8) theory with one fermion in ra
nk-2 symmetric and three fermions in the rank-2 antisymmetric representati
ons\, I will argue that vacuum operators consistent with abelian anomalies
must have very large scaling dimensions and consideration of continuous f
lavor symmetry anomaly ever increase this. This suggests that no single va
cuum operator survives along the RG-trajectory and the theory is more like
ly to flow to IR conformal field theory. Considering another example\, SU(
8) theory with two fermions in rank-2 symmetric and six fermions in the ra
nk-2 antisymmetric representations\, I will again argue that the theory is
highly unlikely to confine and the most feasible possibility is to flow t
o the IR CFT. Interestingly\, these rather remarkable results based on non
-perturbative analysis are consistent with what the perturbative analysis
about the IR fixed point suggests.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edwan Preau (CNRS)
DTSTART:20220817T070000Z
DTEND:20220817T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/87
DESCRIPTION:Title: Chern-Simons term and baryons in holographic QCD\
nby Edwan Preau (CNRS) as part of KIAS Strings Seminar\n\n\nAbstract\nThe
holographic method is one of the only ways of getting analytic insight int
o most strongly coupled systems. When numerical methods are not available\
, it is even the best technique we know of to tackle these problems. In pa
rticular\, lattice QCD is unable to provide results at finite baryon densi
ty\, which is why a lot of effort is put into the study of holographic QCD
at high density. Densities beyond the nuclear density are not only a theo
retical frontier\, but are reached in real systems such as neutron star co
res and future heavy ion collision experiments. In this talk\, I will disc
uss the most elementary aspect of baryonic physics in holography\, that is
the study of a single baryon state. I will start by reviewing the top-dow
n construction of Sakai and Sugimoto\, which makes very clear the crucial
role played by the topological CS term to construct holographic baryons. I
will then introduce the bottom-up framework that we use\, the so-called V
-QCD framework\, and explain how the CS term is built in V-QCD. The last p
art of my presentation will discuss the construction of a baryon solution
in V-QCD\, with the newly determined CS term.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fengjun Xu (BIMSA\, Beijing)
DTSTART:20220801T070000Z
DTEND:20220801T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/88
DESCRIPTION:Title: Topological Defect Lines in Two Dimensional Fermionic
CFTs\nby Fengjun Xu (BIMSA\, Beijing) as part of KIAS Strings Seminar
\n\n\nAbstract\nIn this talk\, we will talk about topological defect lines
(TDLs) in two dimensional (conformal) theories and their roles in categor
y symmetries\, which generalize the notion of symmetries by including non-
invertible elements. In particular\, we will introduce their new features
in 2d Fermionic conformal theories\, as well as their strong constraints i
n the study of RG flows. Followed by that\, we will utilise these strong c
onstraints to study a RG flow with emergent supersymmetry in two dimension
s.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabrizio Del Monte (Université de Montreal)
DTSTART:20220712T020000Z
DTEND:20220712T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/89
DESCRIPTION:Title: Supersymmetric partition functions and isomonodromic
tau functions\nby Fabrizio Del Monte (Université de Montreal) as part
of KIAS Strings Seminar\n\n\nAbstract\nClass S theories are four-dimensio
nal N=2 QFTs that are obtained by wrapping M5-branes on Riemann surfaces w
ith singular points. In recent years a correspondence between class S theo
ries and isomonodromic deformations equations (whose simplest examples are
the six Painlevé equations) is emerging\, where the so-called isomonodro
mic tau function is identified with the dual partition function of the QFT
. The tau functions can be typically written as Fredholm determinants or P
faffians\, providing a fully nonperturbative approach to study partition f
unctions of class S theories\, relying only on the geometric data entering
in the string theory construction\, and not on a classical action.\n\nAft
er reviewing the Fredholm determinant formulation of tau functions for sph
eres with regular singularities\, corresponding to linear quiver gauge the
ories\, I will show how the description can be extended to tau functions w
ith orthogonal gauge groups\, that are written as Fredholm Pfaffians\, and
to tau functions for tori with regular singularities\, corresponding to c
ircular quiver gauge theories. I will conclude by showing how the tau func
tion description allows to study the S-duality transformation of the resul
ting gauge theory dual partition function.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Haowu Wang (IBS-CGP\, Pohang)
DTSTART:20220822T070000Z
DTEND:20220822T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/90
DESCRIPTION:Title: Finite groups and automorphic products\nby Haowu
Wang (IBS-CGP\, Pohang) as part of KIAS Strings Seminar\n\n\nAbstract\nIn
1992 Borcherds proved Monstrous Moonshine Conjecture by lifting Mckay--Tho
mson series to twisted denominator identities of the monster Lie algebra.
Borcherds' proof inspires an intriguing relation between vertex algebras\,
Borcherds--Kac--Moody algebras and automorphic products. In this talk we
introduce several new results related to this relation. We classify nice B
KM algebras whose denominators are automorphic products. We prove twists o
f denominator identities of the fake monster Lie algebra by the Conway gro
up define automorphic products on orthogonal groups. To prove the results\
, we establish a new expression of automorphic products in terms of Jacobi
forms. Using this representation\, we also show that some infinite produc
ts involving twisted elliptic genera of K3 surfaces (appearing in Mathieu
Moonshine) are meromorphic Siegel modular forms on congruence subgroups\,
which proves a conjecture of Miranda Cheng. This talk is based on joint wo
rk with Brandon Williams.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi Zhang (Peking University)
DTSTART:20220824T070000Z
DTEND:20220824T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/91
DESCRIPTION:Title: Gravitational anomalies of higher-spin fields\nby
Yi Zhang (Peking University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nIn this talk\, I will consider local gravitational anomalies of symmetr
ic tensor-spinors (fermionic higher spin fields). This is done by using th
e Atiyah-Singer index theorem and the spectrum of ghosts. We find new anom
aly cancellations within an infinite tower of these fermionic higher spin
fields with alternating chiralities. Time permitting\, I will also talk ab
out the antisymmetric case (fermionic p-forms). The ghost spectrum is foun
d using the Batalin-Vilkovisky field-antifield formalism. We find an intri
guing matching of anomalies between a chiral fermionic p-form and a (D-p-1
)-form.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220823T070000Z
DTEND:20220823T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/93
DESCRIPTION:Title: Four-manifold invariants and Seiberg-Witten theory (1
/4)\nby Heeyeon Kim (Rutgers) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will review the work of Moore and Witten in 1997\, which provided
a path integral derivation of the Donaldson invariants via topologically
twisted 4d supersymmetric gauge theories on a closed four-manifold. If tim
e permits\, I will also report recent progress in understanding analogous
computations in higher dimensions.\n*organizer's comment\; this is the fir
st lecture of three-times-long lecture series.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220825T070000Z
DTEND:20220825T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/94
DESCRIPTION:Title: Four-manifold invariants and Seiberg-Witten theory (2
/4)\nby Heeyeon Kim (Rutgers) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will review the work of Moore and Witten in 1997\, which provided
a path integral derivation of the Donaldson invariants via topologically
twisted 4d supersymmetric gauge theories on a closed four-manifold. If tim
e permits\, I will also report recent progress in understanding analogous
computations in higher dimensions.\n*organizer's comment\; this is the sec
ond lecture of three-times-long lecture series.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Usman Naseer (Uppsala University)
DTSTART:20220905T070000Z
DTEND:20220905T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/95
DESCRIPTION:Title: 7d SYM\, negative coupling and instantons\nby Usm
an Naseer (Uppsala University) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nBeing non-renormalizable\, SYM theories in d>4 are not well-defined by
themselves and need non-trivial UV-completions. Using supersymmetric loca
lization\, one can obtain a glimpse into the structure of these UV complet
ions. Focusing on the 7d SYM\, we show that there is a regime where the ef
fective coupling becomes negative. The theory has instanton branes which c
ontribute to the partition function non-trivially. Remarkably\, the full p
artition functions stays well defined even for negative coupling. Our resu
lts imply that the UV completion has two weakly coupled regimes\, one of w
hich is\, in fact\, gravitational.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220826T070000Z
DTEND:20220826T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/96
DESCRIPTION:Title: Four-manifold invariants and Seiberg-Witten theory (3
/4)\nby Heeyeon Kim (Rutgers) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will review the work of Moore and Witten in 1997\, which provided
a path integral derivation of the Donaldson invariants via topologically
twisted 4d supersymmetric gauge theories on a closed four-manifold. If tim
e permits\, I will also report recent progress in understanding analogous
computations in higher dimensions.\n*organizer's comment\; this is the thi
rd lecture of three-times-long lecture series.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hongfei Shu (BIMSA\, Beijing)
DTSTART:20220919T070000Z
DTEND:20220919T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/97
DESCRIPTION:Title: Wall-crossing of TBA equations and WKB periods for th
e higher order ODE\nby Hongfei Shu (BIMSA\, Beijing) as part of KIAS S
trings Seminar\n\n\nAbstract\nIn this talk\, we study the WKB periods for
the third order ordinary differential equation (ODE) with polynomial poten
tial\, which is obtained by the Nekrasov-Shatashvili limit of ($A_2\,A_N$)
Argyres-Douglas theory in the Omega background. In the minimal chamber of
the moduli space\, we derive the Y-system and the thermodynamic Bethe an
satz (TBA) equations of quantum integrable model by using the ODE/IM corre
spondence. The exact WKB periods are identified with the Y-functions. Vary
ing the moduli parameters of the potential\, the wall-crossing of the TBA
equations occurs. We study the process of the wall-crossing from the min
imal chamber to the maximal chamber for $(A_2\,A_2)$ and $(A_2\,A_3)$ case
. When the potential is a monomial type\, we show the TBA equations obtain
ed from the ($A_2\, A_2$) and ($A_2\, A_3$)-type ODE lead to the $D_4$ and
$E_6$-type TBA equations respectively. This talk is based on the joint wo
rk with Katsushi Ito and Takayasu Kondo arXiv:2111.11047 [hep-th].\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/97/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220830T070000Z
DTEND:20220830T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/98
DESCRIPTION:Title: Four-manifold invariants and Seiberg-Witten theory (4
/4)\nby Heeyeon Kim (Rutgers) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will review the work of Moore and Witten in 1997\, which provided
a path integral derivation of the Donaldson invariants via topologically
twisted 4d supersymmetric gauge theories on a closed four-manifold. If tim
e permits\, I will also report recent progress in understanding analogous
computations in higher dimensions.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuta Hamada (KEK)
DTSTART:20221024T070000Z
DTEND:20221024T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/100
DESCRIPTION:Title: Monopole-fermion scattering and varying Fock space\nby Yuta Hamada (KEK) as part of KIAS Strings Seminar\n\n\nAbstract\nWe
propose a four-dimensional interpretation of the outgoing state of the sc
attering of a massless fermion off a Dirac monopole. It has been known tha
t such a state has fractional fermion numbers and is necessarily outside t
he Fock space on top of ordinary perturbative vacuum\, when more than two
flavours of charged Dirac fermions are considered. In this paper\, we poin
t out that the Fock space of the fermions depends on the rotor degree of f
reedom of the monopole and changes by a monopole-fermion s-wave scattering
. By uplifting the fermion-rotor system introduced by Polchinski\, from tw
o to four dimensions\, we argue that the outgoing state can be understood
as a state in a different Fock space.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/100
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiung Hwang (IBS\, Daejon)
DTSTART:20221031T070000Z
DTEND:20221031T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/101
DESCRIPTION:Title: Rethinking 3d Mirror Symmetry\nby Chiung Hwang (
IBS\, Daejon) as part of KIAS Strings Seminar\n\n\nAbstract\nI'll discuss
how to understand the local S-dualization and the Hanany-Witten transition
of branes in IIB string theory in terms of QFT dualities. This new approa
ch leads to a systematic construction of the mirror dual of any 3d N=4 lin
ear quiver gauge theory only using a set of basic dualities. Also\, I'll d
iscuss a relation between 3d mirror symmetry and Seiberg-like dualities.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/101
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Giacomelli (Milan University)
DTSTART:20221107T070000Z
DTEND:20221107T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/102
DESCRIPTION:Title: A journey through Argyres-Douglas theories\nby S
imone Giacomelli (Milan University) as part of KIAS Strings Seminar\n\n\nA
bstract\nArgyres-Douglas theories are a vast class of N=2 superconformal t
heories in four dimensions characterized by the presence of chiral primary
operators with fractional scaling dimension. Although these models are st
rongly-coupled\, in this talk I will explain how their geometric realizati
on in string theory allows us to extract extremely detailed information ab
out their dynamics and their moduli space of vacua. In particular I will d
iscuss new results I have obtained about the description of their Higgs br
anch and the determination of their generalized symmetries.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/102
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aaron Poole (Kyung Hee University)
DTSTART:20221121T070000Z
DTEND:20221121T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/104
DESCRIPTION:Title: Charges\, conserved quantities\, and fluxes in de Si
tter spacetime\nby Aaron Poole (Kyung Hee University) as part of KIAS
Strings Seminar\n\n\nAbstract\nIn this talk I will discuss conserved quant
ities in asymptotically locally de Sitter (dS) spacetimes\, motivated by t
he broader aim of a developing a fully nonlinear understanding of the natu
re of gravitational waves in dS. I will begin with a review of the asympto
tics of dS spacetimes\, before showing that one can use the tools of the c
ovariant phase space formalism (together with analytic continuation of ana
logous results in anti-de Sitter spacetime) in order to derive expressions
for spatially conserved charges and temporally conserved quantities. I wi
ll present flux formulae which capture the effects of outgoing gravitation
al radiation and illustrate these via application to exact solutions\, wit
h particular emphasis on the Robinson-Trautman dS class. This talk is base
d on https://arxiv.org/pdf/2112.14210.pdf (published in PRD) and upcoming
work in collaboration with Kostas Skenderis and Marika Taylor.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/104
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sahand Seifnashri (IAS)
DTSTART:20221018T010000Z
DTEND:20221018T020000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/105
DESCRIPTION:Title: Representation theory for non-invertible symmetries
and asymptotic density of states\nby Sahand Seifnashri (IAS) as part o
f KIAS Strings Seminar\n\n\nAbstract\nWe discuss non-invertible symmetries
that generalize group-like symmetries in QFTs. We find the appropriate no
tion of representation for non-invertible symmetries needed to derive sele
ction rules on correlation functions. We use this understanding to derive
a Cardy-like formula for 2d CFTs with a finite non-invertible symmetry. Mo
re specifically\, we derive a universal formula for the asymptotic density
of states transforming in an irreducible representation of a non-invertib
le symmetry.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/105
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yasuyuki Hatsuda (Rikkyo University)
DTSTART:20221205T070000Z
DTEND:20221205T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/106
DESCRIPTION:Title: Fermi-gas approach to supersymmetric localization\nby Yasuyuki Hatsuda (Rikkyo University) as part of KIAS Strings Seminar
\n\n\nAbstract\nSupersymmetric localization reduces path integrals to fini
te dimensional matrix integrals. For some particular models\, these matrix
integrals can be regarded as the canonical partition function of ideal Fe
rmi-gas systems. I will first review this Fermi-gas approach in detail. Th
en\, I will talk about our recent application to (a special limit of) supe
rconformal indices.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/106
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Brandon C. Rayhaun (Stony Brook University)
DTSTART:20221213T070000Z
DTEND:20221213T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/107
DESCRIPTION:Title: Classification of Unitary Rational Conformal Field T
heories with Small Central Charge and Few Primaries\nby Brandon C. Ray
haun (Stony Brook University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nTwo-dimensional conformal field theories are ubiquitous in physics and
mathematics. In many applications\, it can be useful to have some kind of
handle on the space of physically consistent theories. It is natural to st
ratify this space in terms of two parameters: the central charge c\, and t
he number of primary operators p. In a classic paper\, Schellekens classif
ied all theories with p=1 primaries and central charge c less than or equa
l to 24. In this talk\, I will describe a strategy for pushing the classif
ication to larger values of p. As a proof of concept\, I will spell out th
e case of p=2\, emphasizing the new concepts at play and highlighting seve
ral future directions. Based on joint work with Sunil Mukhi.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/107
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio\, Parra Martinez (Caltech)
DTSTART:20221219T070000Z
DTEND:20221219T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/108
DESCRIPTION:Title: Causality constraints on gravitational effective the
ories\nby Julio\, Parra Martinez (Caltech) as part of KIAS Strings Sem
inar\n\n\nAbstract\nIn this talk I will describe constraints from causalit
y and unitarity on 2→2 graviton scattering in weakly-coupled gravitation
al effective field theories. Together\, causality and unitarity imply disp
ersion relations that connect low-energy observables to high-energy data.
Using such dispersion relations\, I will explain how to derive two-sided b
ounds on gravitational Wilson coefficients in terms of the mass M of new h
igher-spin states. Such bounds imply that gravitational interactions must
shut off uniformly in the limit G→0\, and prove the scaling with M expec
ted from dimensional analysis. In addition they demonstrate the gravity mu
st be weakly coupled at all scales below Planck.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/108
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Deliang Zhong (Tel Aviv University)
DTSTART:20230206T070000Z
DTEND:20230206T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/109
DESCRIPTION:Title: Line Operators in Chern-Simons-Matter Theories and B
osonization in Three Dimensions\nby Deliang Zhong (Tel Aviv University
) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study Chern-Simons the
ories at large N with either bosonic or fermionic matter in the fundamenta
l representation. The most fundamental operators in these theories are mes
onic line operators\, the simplest example being Wilson lines ending on fu
ndamentals. We classify the conformal line operators along an arbitrary sm
ooth path as well as the spectrum of conformal dimensions and transverse s
pins of their boundary operators at finite 't Hooft coupling. These line o
perators are shown to satisfy first-order chiral evolution equations\, in
which a smooth variation of the path is given by a factorized product of t
wo line operators. We argue that this equation\, together with the spectru
m of boundary operators\, are sufficient to determine these operators' exp
ectation values uniquely. We demonstrate this by bootstrapping the two-poi
nt function of the displacement operator on a straight line. We show that
the line operators in the theory of bosons and the theory of fermions sati
sfy the same evolution equation and have the same spectrum of boundary ope
rators.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/109
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenghao Zhong (Oxford)
DTSTART:20230213T070000Z
DTEND:20230213T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/110
DESCRIPTION:Title: Higgsing SCFTs in d=3\,4\,5\,6\nby Zhenghao Zhon
g (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study supersy
mmetric gauge theories with 8 supercharges in d=3\,4\,5\,6. For these theo
ries\, one can perform Higgsings by turning on VEVs of scalar fields. Howe
ver\, this process can often be difficult when dealing with superconformal
field theories (SCFTs) where the Lagrangian is often not known. Using tec
hniques of magnetic quivers and a new algorithm we call "Inverted Quiver S
ubtraction"\, we show how one can easily obtain the SCFT(s) after Higgsing
. This technique can be equally well applied to SCFTs in d=3\,4\,5\,6.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/110
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rishi Mouland (Cambridge)
DTSTART:20230220T080000Z
DTEND:20230220T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/111
DESCRIPTION:Title: Black Holes in the Dual of Quantum Mechanics\nby
Rishi Mouland (Cambridge) as part of KIAS Strings Seminar\n\n\nAbstract\n
I will motivate and study a holographic duality between on one hand a theo
ry of superconformal quantum mechanics\, and on the other\, M-theory on a
particular background. I will exhibit a broad class of black hole solution
s\, whose entropy must be captured by a degeneracy of states in the quantu
m mechanics. Through an asymptotic study of the superconformal index in th
e supergravity regime\, I will provide such a microstate counting for thos
e black holes that are supersymmetric. I will finally discuss on the role
of dualities of this form in constructing the basic building blocks of hol
ography for SCFTs in various dimensions.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/111
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Nardoni (IPMU)
DTSTART:20230227T070000Z
DTEND:20230227T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/112
DESCRIPTION:Title: Probing Anomalies of Non-Invertible Symmetries with
Symmetry TFTs\nby Emily Nardoni (IPMU) as part of KIAS Strings Seminar
\n\n\nAbstract\n't Hooft anomalies provide crucial insight into the proper
ties of quantum field theories\, imposing powerful constraints on their lo
w energy dynamics. For invertible global symmetries\, it is known that the
't Hooft anomalies can be characterized by an invertible TQFT in one high
er dimension. However\, the analogous statement remains to be understood f
or non-invertible symmetries. In this talk we will discuss how the linking
invariants in a non-invertible TQFT known as the Symmetry TFT can be used
as a diagnostic for the anomalies of non-invertible symmetries. We will i
llustrate this proposal through examples in two and four dimensions\, incl
uding 4d adjoint QCD\, and comment on how knowledge of these anomalies can
impose constraints on the dynamics.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/112
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hossein Yavartanoo (BIMSA)
DTSTART:20230208T070000Z
DTEND:20230208T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/113
DESCRIPTION:Title: Null Surface Thermodynamics\nby Hossein Yavartan
oo (BIMSA) as part of KIAS Strings Seminar\n\n\nAbstract\nFormulating D di
mensional pure Einstein gravity in spacetimes with a null codimension one
boundary requires addition of boundary degrees of freedom (BDOF) to the us
ual bulk gravitons. We construct the solution space perturbatively around
the null boundary in which BDOF is described by D functions on the codimen
sion one null boundary. Employing covariant phase space formalism we compu
te charges associated with symmetries which rotate us within the solution
phase space. We establish that the system admits a thermodynamic descripti
on and that the null surface thermodynamics is a consequence of the diffeo
morphism invariance of the theory\, not relying on other special features
of the null surface or the gravity theory. In the presence of flux of bulk
gravitons through the null boundary we deal with an open thermodynamic sy
stem. Our analysis here extends the usual laws of black hole thermodynamic
s in two ways: it is true for any null surface (which is not necessarily t
he horizon of a black hole) which may describe a system out of thermal equ
ilibrium and that they are local equations over the null surface.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/113
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenz Eberhardt (IAS)
DTSTART:20230307T013000Z
DTEND:20230307T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/114
DESCRIPTION:Title: Evaluating one-loop string amplitudes\nby Lorenz
Eberhardt (IAS) as part of KIAS Strings Seminar\n\n\nAbstract\nI will exp
lain recent work with S. Mizera in which we give explicit evaluations of o
ne-loop open string amplitudes at finite alpha’. Our method involves var
ious deformations of the contour integral over the modular parameter \\tau
. We directly verify that the one-loop string amplitude satisfies unitarit
y constraints. I will show explicit plots of the amplitude which will allo
w us to verify directly physical conjectures about their behavior\, especi
ally at high energies.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/114
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Lotito (SNU)
DTSTART:20230313T070000Z
DTEND:20230313T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/115
DESCRIPTION:Title: Extended operators in 4d N=2 SCFTs and vertex algebr
as\nby Matteo Lotito (SNU) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nLocal Schur operators in 4d N=2 SCFTs form a protected class of operat
ors giving rise to a 2d vertex operator algebra. Following the local opera
tor picture\, we introduce classes of conformal extended operators (lines\
, surfaces) and study these in twisted Schur cohomology. We show how these
operators support a more general algebraic structure compared to the loca
l case\, giving rise to an extension of the vertex algebra known for local
Schur operators.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/115
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minyoung You (Postech)
DTSTART:20230320T070000Z
DTEND:20230320T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/116
DESCRIPTION:Title: MTC/RCFT correspondence: the fermionic story\nby
Minyoung You (Postech) as part of KIAS Strings Seminar\n\n\nAbstract\nIt
is well-known that modular tensor categories (MTC)\, which describe 2+1d b
osonic topological orders\, define a 2+1d topological quantum field theory
(TQFT) and capture the modular data of 1+1d rational conformal field theo
ries (RCFT). After reviewing the bosonic correspondence\, I will explain t
he generalization of this correspondence to the fermionic case: fermionic
topological orders are described by super-MTCs\, their modular extensions
define a 2+1d spin-TQFT\, and they capture the modular data of 1+1d fermio
nic RCFTs. Then I will discuss the classification of super-MTCs and comput
ation of their modular extensions. Finally\, I will discuss the applicatio
n of these classification results to fermionic RCFTs. In particular\, the
knowledge of modular extensions allows us to glean information about the R
-R sector from the data of the NS-NS sector.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/116
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Gu (Bonn)
DTSTART:20230327T070000Z
DTEND:20230327T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/117
DESCRIPTION:Title: Heisenberg Spin Chains And Supersymmetric Gauge Theo
ries\nby Wei Gu (Bonn) as part of KIAS Strings Seminar\n\n\nAbstract\n
In this talk\, we will present how a Heisenberg spin chain emerges from th
e two-dimensional N=(2\,2) gauge theory at an intermediate scale\, which r
elies on the renormalization group flow guided by the global symmetries an
d the dynamics of domain walls. Two examples will be discussed: XX-model a
nd its K-theoretic version. Finally\, we will briefly comment on the unifi
cation of gauge theories from the point of view of the spin chain\, and ho
w to approach other formulations of an integrable system via a new point o
f view.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/117
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Closset (Birmingham)
DTSTART:20230403T070000Z
DTEND:20230403T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/118
DESCRIPTION:Title: The Witten index of 3d N=2 supersymmetric SQCD\, rev
isited: Dualities\, moduli spaces and quantum K-theory\nby Cyril Closs
et (Birmingham) as part of KIAS Strings Seminar\n\n\nAbstract\nI will revi
sit aspects of the physics of 3d unitary SQCD\, a 3d N=2 supersymmetric U(
N) Chern-Simons-matter theory with fundamentals and antifundamental chiral
multiplets. Various subtle aspects come into play when the CS level for t
he U(1) and SU(N) factors are distinct. I will explain how to compute the
Witten index (and other related indices) of this theory explicitly and I w
ill discuss the low-energy physics at non-zero values of the Fayet-Iliopou
los parameter. I will present new detailed checks of infrared dualities in
these theories. Finally\, I will connect this physical story to mathemati
cal results on the quantum K-theory of Grassmannian manifolds. This involv
es constructing new families of line operators in the 3d gauge theory.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/118
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michèle Levi (Oxford)
DTSTART:20230406T030000Z
DTEND:20230406T040000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/119
DESCRIPTION:Title: Modern QFT for Real-World Gravity (I)\nby Michè
le Levi (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nPart 1\n-R
eal-World Context\n-Tower of EFTs for PN Gravity\n-Overview of Effective F
ield Theories\nPart 2\n-Bootstrapping One-Particle EFT\n-Tower of EFTs for
Binary Inspiral\n-Bootstrapping EFT of Spinning Particle\nPart 3\n-Feynma
n Rules & Graph Topologies\n-Leading PN Corrections & Observables\n-Multil
oops & Public PN Code\nPart 4\n-Higher Spin\n-Higher Loop\n-Beyond Conserv
ative Sector\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/119
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michèle Levi (Oxford)
DTSTART:20230410T070000Z
DTEND:20230410T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/120
DESCRIPTION:Title: Modern QFT for Real-World Gravity (II)\nby Mich
èle Levi (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nPart 1\n
-Real-World Context\n-Tower of EFTs for PN Gravity\n-Overview of Effective
Field Theories\nPart 2\n-Bootstrapping One-Particle EFT\n-Tower of EFTs f
or Binary Inspiral\n-Bootstrapping EFT of Spinning Particle\nPart 3\n-Feyn
man Rules & Graph Topologies\n-Leading PN Corrections & Observables\n-Mult
iloops & Public PN Code\nPart 4\n-Higher Spin\n-Higher Loop\n-Beyond Conse
rvative Sector\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/120
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin Kaidi (University of Washington)
DTSTART:20230418T020000Z
DTEND:20230418T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/121
DESCRIPTION:Title: Non-Supersymmetric Heterotic Branes\nby Justin K
aidi (University of Washington) as part of KIAS Strings Seminar\n\n\nAbstr
act\nThe common statement that any consistent quantum gravity theory conta
ins dynamical objects with all possible charges suggests that there are st
ill a number of hitherto-unidentified branes in string theory. In this tal
k I will discuss four of these new branes\, focusing on heterotic string t
heories. The focus of the discussion will be on the relationship between t
hese branes and the lower-dimensional vacua obtained by closed string tach
yon condensation in the ten-dimensional\, non-supersymmetric heterotic str
ing theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/121
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amir-Kian Kashani-Poor (ENS Paris)
DTSTART:20230424T080000Z
DTEND:20230424T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/122
DESCRIPTION:Title: Elliptic genera of non-critical strings and the worl
dsheet\nby Amir-Kian Kashani-Poor (ENS Paris) as part of KIAS Strings
Seminar\n\n\nAbstract\nMany tools have been developed in recent years to c
ompute the elliptic genera of 6d non-critical strings. The latter are exci
tations of 6d superconformal field theories\, best defined via F-theory co
mpactifications on Calabi-Yau manifolds. The elliptic genera contain infor
mation both regarding the 6d target space theory and the IR theory on the
string worldsheet. The worldsheet aspect will be the focal point of this t
alk. We will review what is known about this IR theory\, in particular reg
arding its symmetries\, and then formulate an ansatz for the elliptic genu
s in which these symmetries are manifest. We have checked this ansatz for
many examples\, some of which we shall discuss. This talk is based on join
t work with David Jaramillo Duque.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/122
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sangmin Lee (Seoul National University)
DTSTART:20230501T070000Z
DTEND:20230501T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/123
DESCRIPTION:Title: Classical observables from partial wave amplitudes\nby Sangmin Lee (Seoul National University) as part of KIAS Strings Sem
inar\n\n\nAbstract\nWe study the formalism of Kosower-Maybee-O’Connell (
KMOC) to extract classical impulse from quantum amplitude in the context o
f the partial wave expansion of a 2-to-2 elastic scattering. We take two c
omplementary approaches to establish the connection. The first one takes a
dvantage of Clebsch-Gordan relations for the base amplitudes of the partia
l wave expansion. The second one is a novel adaptation of the traditional
saddle point approximation in the semi-classical limit. In the former\, an
interference between the S-matrix and its conjugate leads to a large degr
ee of cancellation such that the saddle point approximation to handle a ra
pidly oscillating integral is no longer needed. As an example with a non-o
rbital angular momentum\, we apply our methods to the charge- monopole sca
ttering problem in the probe limit and reproduce both of the two angles ch
aracterizing the classical scattering. A spinor basis for the partial wave
expansion\, a non-relativistic avatar of the spinor-helicity variables\,
plays a crucial role throughout our computations.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/123
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Ferrari (Université libre de Bruxelles)
DTSTART:20230417T070000Z
DTEND:20230417T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/124
DESCRIPTION:Title: Random Disks of Constant Curvature\nby Frank Fer
rari (Université libre de Bruxelles) as part of KIAS Strings Seminar\n\n\
nAbstract\nTwo-dimensional quantum gravity models fall in three classes: L
iouville gravity\, for which the geometry is wildly random in the bulk\; t
opological gravity\, for which the geometries\, having constant curvature
and geodesic boundaries\, have a finite number of moduli\; and an intermed
iate class of models\, which has attracted a lot of attention recently\, f
or which the metrics have constant curvature but the boundaries can fluctu
ate wildly. These so-called Jackiw-Teitelboim models have been studied in
the physics literature\, mainly for negative curvature\, in a certain infi
nite cutoff limit for which the boundary length goes to infinity. \n\nThe
aim of the talk will be to present a first-principle approach to JT gravit
y without assuming that a particular limit is taken\, mainly focusing on t
he disk topology. Because the curvature is fixed\, the randomness entirely
comes from the fluctuating disk boundary\, which is a closed curve immers
ed in the hyperbolic space\, the plane or the sphere. The goal is thus to
count closed curves that bound a disk\, a very interesting and non-trivial
combinatorial problem. Our construction\, which relies on good old confor
mal gauge techniques and insights from recent developments\, yields a new
class of random geometrical models with many properties that remain to be
explored. An important upshot of the analysis is that the ansatz and tools
that have been used in the infinite cutoff limit cannot be used for any f
inite value of the cutoff\, even very large.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/124
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jung-Wook Kim (Albert Einstein Institute)
DTSTART:20230508T070000Z
DTEND:20230508T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/125
DESCRIPTION:Title: Frame-dragging effects in scattering amplitudes\
nby Jung-Wook Kim (Albert Einstein Institute) as part of KIAS Strings Semi
nar\n\n\nAbstract\nIn general relativity\, the gravitational field generat
ed by a spinning body causes immersed test bodies to co-rotate with the ce
ntral body\, which is also known as the frame-dragging effect. One manifes
tation of this effect is known as the gravitational Faraday rotation\, whe
re the polarisation direction of a linearly polarised electromagnetic/grav
itational wave rotates due to the background gravitomagnetic field when pa
ssing by a spinning body. How the effect can be computed using quantum fie
ld theory scattering amplitudes\, how the calculation connects with the gr
avitational two-body problem with spin relevant for gravitational wave phy
sics\, and what the calculations tell us about universal predictions of qu
antum gravity in the infrared\, will be discussed.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/125
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiming Chang (Tsinghua University)
DTSTART:20230515T070000Z
DTEND:20230515T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/126
DESCRIPTION:Title: Meromorphic Celestial Amplitudes\nby Chiming Cha
ng (Tsinghua University) as part of KIAS Strings Seminar\n\n\nAbstract\nCe
lestial holography aims to provide a concrete realization of holographic p
rinciples for quantum gravity in asymptotically flat spacetime. It maps fo
ur-dimensional scattering amplitudes to celestial amplitudes on the two-di
mensional celestial sphere. However\, celestial amplitudes are known to su
ffer from two major problems that prevent them from being interpreted as c
orrelation functions of a 2d conformal field theory (CFT). First\, massles
s three-point celestial amplitudes are considered to be zero in the litera
ture. Second\, the massless four-point celestial amplitudes are distributi
ons rather than meromorphic functions. I will discuss massless celestial a
mplitudes in a new prescription based on the shadow inner product. The res
ults are free from the previous two problems and take the standard form of
CFT correlators.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/126
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masahito Yamazaki (IPMU)
DTSTART:20230522T070000Z
DTEND:20230522T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/127
DESCRIPTION:Title: Revisiting the Gauge/Bethe Correspondence\nby Ma
sahito Yamazaki (IPMU) as part of KIAS Strings Seminar\n\n\nAbstract\nThe
Gauge/Bethe correspondence claims an equivalence between\n(1) the vacuum e
quation of supersymmetric gauge theories with four\nsupercharges and (2) t
he Bethe Ansatz equations in quantum integrable\nmodels. While many papers
have been written about this subject in\nphysics and mathematics\, it is
not yet known how general the\ncorrespondence should hold---at least that
has been my opinion for the\npast decades. In this talk\, I will discuss t
he general applicability\nof the Gauge/Bethe correspondence using the repr
esentations of the\nquiver BPS algebras\, following my research arXiv:2206
.13340 [hep-th]\nwith Dimitry Galakhov and Wei Li.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/127
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yunqin Zheng (IPMU)
DTSTART:20230605T070000Z
DTEND:20230605T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/128
DESCRIPTION:Title: Revisiting bosonization and fermionization\nby Y
unqin Zheng (IPMU) as part of KIAS Strings Seminar\n\n\nAbstract\nBosoniza
tion and fermionization are useful tools in studying 1+1d quantum systems.
I will first revisit this topic from the perspective of topological phase
s. In particular\, I will explain a confusing situation where bosonization
“backfires” — bosonizing a fermionic theory still yields a fermioni
c theory — and explain how this puzzle is resolved. I will then apply th
ese understandings to the problem of classification of fermionic chiral CF
Ts with central charge c<=16.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/128
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karapet Mkrtchyan (Imperial College\, London)
DTSTART:20230614T070000Z
DTEND:20230614T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/129
DESCRIPTION:Title: Actions for (twisted) self-duality equations\, their
abelian interacting generalizations and applications\nby Karapet Mkrt
chyan (Imperial College\, London) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will summarise the ongoing research program\, where we derive Lor
entz invariant Lagrangians for first order equations describing p-form dyn
amics\, and apply them for several well-known problems.\nFirst\, we derive
the most general non-linear electrodynamics theory in 3+1 dimensions in a
democratic formulation\, where electric and magnetic potentials enter on
equal footing. This includes infinitely many duality-symmetric theories wh
ere both S-duality and Lorentz invariance are manifest symmetries of the a
ction.\nNext\, we derive non-linear self-interactions of self-dual (chiral
) p-forms in Minkowski spaces of d=4k+2 dimensions\, for which the Lorentz
-covariant formulation is usually challenging even for the free action. We
then generalize these results to a democratic description of arbitrary ab
elian interacting p-forms in arbitrary dimensions.\nWe also apply our form
ulation to derive actions for type II supergravities in 9+1 dimensions emp
loying a democratic description of all RR fields. For type IIB\, the self-
duality equation for the five form is a consequence of the Euler-Lagrange
equations\, as opposed to pseudo-action formulations.\nTime permitting\, I
will compare our formulation to other existing ones as well as mention an
ongoing work relating these results to another formulation via topologica
l field theory\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/129
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Muyang Liu (Uppsala University)
DTSTART:20230628T070000Z
DTEND:20230628T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/130
DESCRIPTION:Title: Back to Heterotic Little String Theories on ALE Spac
es\nby Muyang Liu (Uppsala University) as part of KIAS Strings Seminar
\n\n\nAbstract\nI will revisit some features of Heterotic little strings o
n ALE spaces motivated by recent developments in our understanding of the
structures of six-dimensional theories and their continuous 2-group symmet
ries. In particular\, the construction of novel Heterotic E8 × E8 ALE ins
tantonic theories through the 6d conformal matter approach is presented\,
which extends previous results explored by Aspinwall and Morrison as well
as Blum and Intriligator. This results in the predictions of their T-dual
partners via the matching of the Coulomb branch and tensor branch data. Th
e identification of dual Little String Theory (LST) is then confirmed thro
ugh the geometric engineering in F-theory\, where the T-dual system is rea
lized as the inequivalent elliptic fibration structure of the same geometr
y. In the end\, this architecture also inspires us to investigate the geom
etric engineering limit of heterotic strings on ALE spaces.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/130
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergei Kuzenko (University of Western Australia)
DTSTART:20230629T070000Z
DTEND:20230629T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/131
DESCRIPTION:Title: Non-compact duality\, super-Weyl invariance and effe
ctive actions\nby Sergei Kuzenko (University of Western Australia) as
part of KIAS Strings Seminar\n\n\nAbstract\nThis talk will review recent r
esults on the quantum dynamics of a system of n Abelian N = 1 vector multi
plets coupled to (1/2) n(n+1) chiral multiplets which parametrise the Herm
itian symmetric space Sp(2n\, R)/ U(n). In the presence of supergravity\,
this model is super-Weyl invariant and possesses the maximal non-compact d
uality group Sp(2n\, R) at the classical level. These symmetries are shown
to be respected by the logarithmically divergent term (the ``induced acti
on'') of the effective action obtained by integrating out the vector multi
plets. In computing the effective action\, one has to deal with non-minima
l operators for which the known heat kernel techniques are not directly ap
plicable\, even in flat (super)space. The induced action is derived in clo
sed form and has a simple structure. It is a higher-derivative N = 1vsuper
conformal sigma model on Sp(2n\, R)/ U(n). The obtained N = 1 results are
then generalised to the case of N = 2 local supersymmetry\, specifically:
a system of n Abelian N = 2 vector multiplets coupled to N = 2 chiral scal
ar multiplets parametrising Sp(2n\, R}/ U(n). The induced action is of the
type proposed\, in particular\, by Gomis\, Hsin\, Komargodski\, Schwimmer
\, Seiberg and Theisen.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/131
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tadashi Okazaki (Southeast University)
DTSTART:20230623T070000Z
DTEND:20230623T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/132
DESCRIPTION:Title: Asymptotic degeneracies of M2-brane SCFTs\nby Ta
dashi Okazaki (Southeast University) as part of KIAS Strings Seminar\n\n\n
Abstract\nWe study the asymptotic growth of the degeneracy of the BPS loca
l operators with large scaling dimensions in the three-dimensional superco
nformal field theories describing N M2-branes. From the large N supersymme
tric indices we obtain the asymptotic formulas for degeneracies of the M2-
brane SCFTs according to the Meinardus theorem. We observe an intriguing u
niversal $n^{2/3}$ growth of the degeneracies for various theories of M2-b
rane SCFTs. This talk is based on the upcoming work with Hirotaka Hayashi
and Tomoki Nosaka.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/132
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Si Li (Tsinghua University)
DTSTART:20230711T070000Z
DTEND:20230711T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/133
DESCRIPTION:Title: Elliptic Chiral Index and Holomorphic Anomaly\nb
y Si Li (Tsinghua University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nWe investigate a two-dimensional chiral analogue of the algebraic index
theorem via the theory of chiral algebras developed by Beilinson and Drin
feld. We construct a trace map on the elliptic chiral homology of the free
beta gamma-bc system\, and explain the corresponding holomorphic anomaly
equation.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/133
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Max Hubner (University of Pennsylvania)
DTSTART:20230712T070000Z
DTEND:20230712T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/134
DESCRIPTION:Title: Generalized Global Symmetries and Gravity\nby Ma
x Hubner (University of Pennsylvania) as part of KIAS Strings Seminar\n\n\
nAbstract\nGeneralized global symmetries are ubiquitous in QFTs. Given a Q
FT\, exhibiting such symmetries and admitting an embedding into string the
ory\, we may ask what the stringy lift of the corresponding defect and sym
metry operators are. In many cases both are realized by branes\, wrapped o
n non-compact cycles\, and are well-understood in large classes of example
s. However\, once the QFT is coupled to gravity\, general considerations l
ead to the expectation that these symmetries are gauged or broken. We cons
ider these and related phenomena in the context of geometric engineering\,
and geometrize how completing a local model to a global model leads to di
ssolution of symmetry structures.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/134
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashish Shukla (Ecole Polytechnique\, CPHT)
DTSTART:20230822T050000Z
DTEND:20230822T060000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/135
DESCRIPTION:Title: Hydrodynamic transport with broken translation invar
iance\nby Ashish Shukla (Ecole Polytechnique\, CPHT) as part of KIAS S
trings Seminar\n\n\nAbstract\nHydrodynamics provides an effective macrosco
pic description for systems near thermal equilibrium. Conservation equatio
ns for the currents associated to various symmetries of the system\, along
with their constitutive relations expressed as an expansion in gradients\
, encapsulate the dynamics of the system. However\, in real life systems\,
some of the assumed symmetries might get weakly broken. For instance\, th
e presence of impurities can lead to a weak explicit breaking of translati
on invariance\, and consequently momentum relaxation. In this talk\, I wil
l discuss a systematic approach for constructing a hydrodynamic theory whi
ch incorporates leading and subleading momentum relaxing effects. The posi
tivity of entropy production out of equilibrium\, along with Onsager recip
rocity relations\, constrain the hydrodynamic theory. It turns out that th
e leading momentum relaxing effects are captured by a single dissipative t
ransport parameter that leads to a Drude-like peak in the thermoelectric r
esponse of the system. Interestingly\, the subleading effects are captured
by two transport parameters which effectively renormalize the weights of
the Drude peaks in the thermoelectric response. Consequently\, one has to
be careful while extracting thermodynamic data from thermoelectric transpo
rt measurements.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/135
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20230825T050000Z
DTEND:20230825T070000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/136
DESCRIPTION:Title: Recent progress and challenges in moduli stabilizati
on\nby Manki Kim (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\n
One of the most important challenges in string phenomenology is to find se
mi realistic vacua that accommodate features of our universe. As the prope
rties of isolated vacua are determined dynamically\, via moduli stabilizat
ion\, it is crucial to understand moduli stabilization. In the first part
of this talk\, I will review moduli stabilization scenarios in string theo
ry. This will include type II string theories\, Calabi-Yau compactificatio
ns\, flux compactifications (GKP)\, and KKLT type scenarios. In the second
part of the talk\, I will review recent progress and challenges with the
outlook.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/136
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20230828T070000Z
DTEND:20230828T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/137
DESCRIPTION:Title: Recent progress and challenges in moduli stabilizati
on\nby Manki Kim (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\n
One of the most important challenges in string phenomenology is to find se
mi realistic vacua that accommodate features of our universe. As the prope
rties of isolated vacua are determined dynamically\, via moduli stabilizat
ion\, it is crucial to understand moduli stabilization. In the first part
of this talk\, I will review moduli stabilization scenarios in string theo
ry. This will include type II string theories\, Calabi-Yau compactificatio
ns\, flux compactifications (GKP)\, and KKLT type scenarios. In the second
part of the talk\, I will review recent progress and challenges with the
outlook.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/137
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Inst.)
DTSTART:20230904T070000Z
DTEND:20230904T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/138
DESCRIPTION:Title: Deconfinement in 3d gauge theories\nby Changha C
hoi (Perimeter Inst.) as part of KIAS Strings Seminar\n\n\nAbstract\nOne o
f the important characterization of gauge theory dynamics is whether theor
y exhibits confinement or deconfinement. After reviewing well established
examples in 4d and 2d\, we discuss 3d case where several new complications
occur. We then explain how does deconfinement happens in some of the simp
lest non-abelian 3d gauge theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/138
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kohki Kawabata (Tokyo U.)
DTSTART:20231030T070000Z
DTEND:20231030T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/139
DESCRIPTION:Title: Supersymmetric conformal field theories from quantum
stabilizer codes\nby Kohki Kawabata (Tokyo U.) as part of KIAS String
s Seminar\n\n\nAbstract\nWe construct fermionic conformal field theories (
CFTs) whose spectra are characterized by quantum stabilizer codes. We expl
oit our construction to search for fermionic CFTs with supersymmetry by fo
cusing on quantum stabilizer codes of the Calderbank-Shor-Steane type\, an
d derive simple criteria for the theories to be supersymmetric. We provide
several examples of fermionic CFTs that meet the criteria\, and find quan
tum codes that realize N=4 supersymmetry. Our work constitutes a new appli
cation of quantum codes and paves the way for the methodical search for su
persymmetric CFTs.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/139
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takuya Okuda (Tokyo U.\, Komaba)
DTSTART:20231031T050000Z
DTEND:20231031T060000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/140
DESCRIPTION:Title: Narain CFTs and Chern-Simons theories for quantum co
des\nby Takuya Okuda (Tokyo U.\, Komaba) as part of KIAS Strings Semin
ar\n\n\nAbstract\nThe theories of classical and quantum codes have rich ma
thematical structures that capture interesting properties of quantum many-
body physics. In this talk\, we study the gauging of a Z2 symmetry in the
Narain conformal field theories (CFTs) constructed from the data defining
(qudit) quantum error-correcting codes. For both orbifold and fermioniza
tion\, the Z2 gauging procedures can be related to modifications of the mo
mentum lattice by vectors characterizing the Z2 symmetry. We provide thre
e-dimensional interpretations of such Z2 gaugings in terms of Abelian Cher
n-Simons theories\, some of which play the role of symmetry topological fi
eld theories and are related to others by gauging 1-form symmetries. Code
s arise as data defining topological boundary conditions for the Chern-Sim
ons theories. Our bulk construction provides a viewpoint complementary to
the recent alternative holographic interpretation of Narain code CFTs in
the literature.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/140
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yein Lee (Kyung Hee U.)
DTSTART:20230918T070000Z
DTEND:20230918T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/141
DESCRIPTION:Title: Symmetry Breaking and Consistent Truncations from M5
-branes Wrapping a Disc\nby Yein Lee (Kyung Hee U.) as part of KIAS St
rings Seminar\n\n\nAbstract\nWe construct new supersymmetric solutions cor
responding to M5-branes wrapped on a topological disc by turning on additi
onal scalars in the background. The presence of such scalar fields breaks
one of the U(1) isometries of the internal space\, explicitly realising th
e breaking by the Stückelberg mechanism observed previously. In addition\
, we construct a consistent truncation of maximal seven dimensional gauged
supergravity on the disc to five-dimensional Romans' SU(2) × U(1) gauged
supergravity\, allowing us to construct a plethora of new supergravity so
lutions corresponding to more general states in the dual SCFTs as well as
solutions corresponding to M5-branes wrapping four-dimensional orbifolds.\
n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/141
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Norton Lee (IBS)
DTSTART:20230925T070000Z
DTEND:20230925T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/142
DESCRIPTION:Title: Separation of variables and bispectral duality via s
urface instanton\nby Norton Lee (IBS) as part of KIAS Strings Seminar\
n\n\nAbstract\nThe N=2 gauge theories in 4 dimension have an intrinsic con
nection to algebraic integrable system. The gauge theory of our interest\,
the asymptotically N=2 superconformal SQCD in 4d\, reveals the structure
which has bispectral description. On one hand it is a complex generalizati
on of the Heisenberg spin chain based on the sl_2 Lie algebra. On the othe
r hand it is a special case of Gaudin model (a special case of Hitchin sys
tem) based on sl_N Lie algebra. We study the instanton partition function
in the presence of co-dimensional two defects. We prove that the surface i
nstanton partition function\, which can be expressed as an integration in
the separated variables by Sklyanin\, is the eigenfunction of the bispectr
al integrable systems.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/142
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jaewon Song (KAIST)
DTSTART:20231016T070000Z
DTEND:20231016T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/143
DESCRIPTION:Title: Emergent N=4 Supersymmetry from N=1\nby Jaewon S
ong (KAIST) as part of KIAS Strings Seminar\n\n\nAbstract\nWe discover a f
our-dimensional N=1 supersymmetric field theory that is dual to the N=4 su
per Yang-Mills theory with gauge group SU(2n+1) for each n. The dual theor
y is constructed through the diagonal gauging of the SU(2n+1) flavor symme
try of three copies of a strongly coupled superconformal field theory (SCF
T) of Argyres-Douglas type. We find that this theory flows in the infrared
to a strongly coupled N=1 SCFT that lies on the same conformal manifold a
s N=4 super Yang-Mills with gauge group SU(2n+1). Our construction provide
s a hint on why certain N=1\, 2 SCFTs have identical central charges (a=c)
.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/143
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ruben Minasian (IPhT\, Saclay)
DTSTART:20231024T020000Z
DTEND:20231024T033000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/144
DESCRIPTION:Title: Anomalies and beyond - some modern applications\
nby Ruben Minasian (IPhT\, Saclay) as part of KIAS Strings Seminar\n\n\nAb
stract\nExistence of an anomaly cancellation mechanism in (super)gravity t
heories serves as a good guideline for selecting candidates for theories t
hat can be fully consistent at the quantum level. In this talk I will revi
ew various aspects and somewhat surprising consequences of cancellation of
(different types of) anomalies in eight and six dimensions. I will also d
iscuss appearance and importance of more exotic (singular\, non-spin\, non
-orientable) backgrounds.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/144
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kang-Sin Choi (Ewha Women's U.)
DTSTART:20231106T070000Z
DTEND:20231106T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/145
DESCRIPTION:Title: Renormalization and the Hierarchy Problem\nby Ka
ng-Sin Choi (Ewha Women's U.) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nWe reconsider the renormalization of observables\, not bare parameters\
, in quantum field theory. We have a better understanding of the finitenes
s and the scheme independence of physical parameters\, especially of the s
calar mass. After reviewing the vacuum polarization whose quadratic diverg
ence is illusory\, we calculate the top-quark correction to the Higgs mass
\, which is finite\, exhibits power running and is independent of the Wils
onian cutoff.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/145
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Dorey (Cambridge U.\, DAMTP)
DTSTART:20231127T070000Z
DTEND:20231127T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/146
DESCRIPTION:Title: Building a Black Hole in Quantum Mechanics\nby N
ick Dorey (Cambridge U.\, DAMTP) as part of KIAS Strings Seminar\n\n\nAbst
ract\nI will describe recent progress in formulating and testing a dual ho
lographic description of ultra-spinning black holes in terms of finite dim
ensional quantum mechanics.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/146
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ram Brustein (Ben-Gurion University)
DTSTART:20231120T070000Z
DTEND:20231120T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/147
DESCRIPTION:Title: What’s inside a black hole?\nby Ram Brustein (
Ben-Gurion University) as part of KIAS Strings Seminar\n\n\nAbstract\nI wi
ll present general arguments\, based on fundamental physics principles\, a
s to why we should expect a significant\, horizon scale\, departure from s
emiclassical gravity inside astrophysical black holes. Then\, I will prese
nt a simple model which realizes this idea: the frozen star model. I will
show that a static frozen star looks exactly like a Schwarzschild black ho
le to an external observer and that it is sourced by a “string fluid
”. Then I will present the rotating frozen star and show that it looks e
xactly like a Kerr black hole to an external observer. I will end by discu
ssing the stability and the spectrum of internal modes of the frozen stars
and show that they possess an interesting spectrum of non-relativistic mo
des.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/147
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Linardopoulos (APCTP)
DTSTART:20231207T070000Z
DTEND:20231207T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/148
DESCRIPTION:Title: Holographic correlators of semiclassical states in d
efect CFTs\nby Georgios Linardopoulos (APCTP) as part of KIAS Strings
Seminar\n\n\nAbstract\nWe set up the computation of correlation functions
for operators that are dual to semiclassical string states in strongly cou
pled defect conformal field theories (dCFTs). In the dCFT that is dual to
the D3-D5 probe-brane system\, we calculate the correlation function of tw
o heavy operators perturbatively\, in powers of the conformal ratio. We fi
nd that the leading term agrees with the prediction of the operator produc
t expansion (OPE). In the case of two heavy BMN operators\, we find agreem
ent in subleading orders as well.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/148
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomasevic (University of Amsterdam)
DTSTART:20231218T080000Z
DTEND:20231218T090000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/149
DESCRIPTION:Title: The correspondence between rotating black holes and
fundamental strings\nby Marija Tomasevic (University of Amsterdam) as
part of KIAS Strings Seminar\n\n\nAbstract\nThe correspondence principle b
etween strings and black holes is a general framework for matching black h
oles and massive states of fundamental strings at a point where their phys
ical properties (such as mass\, entropy and temperature) smoothly agree wi
th each other. This correspondence becomes puzzling when attempting to inc
lude rotation: At large enough spins\, there exist degenerate string state
s that seemingly cannot be matched to any black hole. Conversely\, there e
xist black holes with arbitrarily large spins that cannot correspond to an
y single-string state. We discuss in detail the properties of both types o
f objects and find that a correspondence that resolves the puzzles is poss
ible by adding dynamical features and non-stationary configurations to the
picture. Our scheme incorporates all black hole and string phases as part
of the correspondence\, save for one outlier which remains enigmatic: the
near-extremal Kerr black hole. Along the way\, we elaborate on general as
pects of the correspondence that have not been emphasized before.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/149
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Saebyeok Jeong (CERN)
DTSTART:20240117T070000Z
DTEND:20240117T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/150
DESCRIPTION:Title: Q-operators as surface defects\; bispectral duality
and separation of variables by surface defect transition\nby Saebyeok
Jeong (CERN) as part of KIAS Strings Seminar\n\n\nAbstract\nI will first e
xplain how the quantum integrable system arising from the 4d N=2 gauge the
ory can be viewed as a XXX spin chain defined on bi-infinite Yangian modul
es. I will present the "regular monodromy" surface defect that provides a
distinguished basis of this module by their vevs at discrete loci in the s
pace of Coulomb vacua. Then I will introduce the "canonical" surface defec
t on top of it which serves as the Q-operator. The action of the Q-operato
r will be shown to be diagonal due to the cluster decomposition of the sur
face defects. As a consequence\, the mentioned basis elements simultaneous
ly diagonalize the transfer matrices of the Yangian. I will connect this X
XX spin chain with a Hitchin integrable system (a Gaudin model in our case
) by embedding the 4d N=2 theory into string/M-theory and applying a strin
g duality. I will show the Coulomb/Higgs transition that the canonical sur
face defect undergoes manifests as the transition between the Q-operator f
or the XXX spin chain and the Hecke operator for the Gaudin model. It lead
s to an exact one-to-one matching between their quantum Hamiltonians as we
ll as their quantum spectra. Finally\, I will explain how the regular mono
dromy surface defect experiences a transition to multiple canonical surfac
e defects. The transition leads to the quantum separation of variables for
both the XXX spin chain and the Gaudin model.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/150
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Albrecht Klemm (BCTP\, U. Bonn)
DTSTART:20240215T013000Z
DTEND:20240215T023000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/151
DESCRIPTION:Title: Calabi-Yau period motives in quantum field theory an
d general relativity\nby Albrecht Klemm (BCTP\, U. Bonn) as part of KI
AS Strings Seminar\n\n\nAbstract\nWe show that Feynman integrals occurring
in standard quantum field theories or perturbative worldline approaches t
o the scattering of real black holes are related to periods of Calabi-Yau
varieties of various dimensions. After defining what mathematical properti
es a Calabi-Yau period motive has\, we explain how the applications of the
latter lead to an efficient analytic evaluation of the Feynman integrals
in dimensional regularisation.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/151
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohammad Akhond (Kyoto University)
DTSTART:20240226T070000Z
DTEND:20240226T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/152
DESCRIPTION:Title: 5d SCFTs and their non-supersymmetric cousins\nb
y Mohammad Akhond (Kyoto University) as part of KIAS Strings Seminar\n\n\n
Abstract\nI will argue that combining old ideas such as dualities and exac
t results in SUSY QFTs supplemented with recent techniques such as SPT pha
ses and generalised anomalies can shed light on strong coupling dynamics o
f non-SUSY theories. I will in particular show that non-SUSY gauge theorie
s\, which are related to SUSY SCFTs by RG in 5d exhibit phase transitions
in the UV which are candidates for non-SUSY fixed points.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/152
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Institute)
DTSTART:20240228T020000Z
DTEND:20240228T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/153
DESCRIPTION:Title: Exact results for surface defect in N=4 SYM\nby
Changha Choi (Perimeter Institute) as part of KIAS Strings Seminar\n\n\nAb
stract\n1/2 BPS surface defect (Gukov-Witten operator) in N=4 SYM is an ex
traordinarily rich physical probe where various non-trivial defect correla
tion functions have been computed in the strong coupling limit using the A
dS/CFT correspondence. From these results\, there has been a long standing
conjecture about some exact matrix model description of the defect correl
ation functions. In this talk\, we corroborate and also improve the conjec
ture using supersymmetric localization.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/153
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changhyun Ahn (Kyungpook Natl. U.)
DTSTART:20240318T070000Z
DTEND:20240318T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/154
DESCRIPTION:Title: On Celestial Holography\nby Changhyun Ahn (Kyung
pook Natl. U.) as part of KIAS Strings Seminar\n\n\nAbstract\nA quantum gr
avity is an outstanding open problem in the current modern physics. The co
mplete theory of quantum gravity would provide the microscopic structure u
nderlying systems whose long distance behavior is described by the general
relativity of Einstein’s theory. Celestial holography studied during la
st ten years provides a new approach to quantum gravity in four dimensiona
l asymptotically flat spacetimes by searching for its holographic correspo
ndence. Celestial holography proposes a duality between gravitational scat
tering in four dimensional asymptotically flat spacetimes and a conformal
field theory living on the two dimensional celestial sphere. I will presen
t 1) Introduction\, 2) Infrared structure of gravity\, 3) From four dimens
ional gravity to two dimensional celestial conformal field theory\, 4) Cel
estial amplitudes and celestial OPEs\, 5) Soft symmetries\, 6) My recent w
orks\, and 7) Open problems. This will provide the way to observe directly
(or indirectly) the evidence of superstring (or M) theory in our real wor
ld.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/154
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Vikman (FZU\, CAS)
DTSTART:20240325T070000Z
DTEND:20240325T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/155
DESCRIPTION:Title: More on Stable Ghosts\nby Alexander Vikman (FZU\
, CAS) as part of KIAS Strings Seminar\n\n\nAbstract\nI will discuss our r
ecent works Phys.Rev.Lett. 128 (2022) 4\, 041301 and e-Print: 2305.09631.
There we presented a large class of mechanical models where a canonical de
gree of freedom interacts with another one with a negative kinetic term\,
i.e.\, with a ghost and yet the system is totally stable. We proved analyt
ically that the classical motion of the system is finite i.e. Lagrange sta
ble for all initial conditions\, notwithstanding that the conserved Hamilt
onian is unbounded from below and above. Moreover\, there are Lyapunov sta
ble equilibrium configurations. Numerical computations fully supported thi
s. An important update is that such stable ghosts can also appear in syste
ms with a simple polynomial interaction. Systems with negative kinetic ter
ms often appear in modern cosmology\, quantum gravity\, and high energy ph
ysics\, and are usually deemed as unstable. Our result demonstrates that\,
for mechanical systems\, this common lore can be too naïve and that a st
able living with ghosts is possible.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/155
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Seok Kim (POSTECH)
DTSTART:20240408T070000Z
DTEND:20240408T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/156
DESCRIPTION:Title: On the monotonicity of the renormalization group flo
w in both nonequilibrium thermodynamics and geometrical perspectives\n
by Ki-Seok Kim (POSTECH) as part of KIAS Strings Seminar\n\n\nAbstract\nFo
llowing the entropy production in nonequilibrium thermodynamics\, we show
the monotonicity of the renormalization group (RG) flow. Then\, we clarify
the connection between the monotonicity of the RG flow and the Weyl anoma
ly\, discussing the a- or c-theorem. To investigate the monotonicity of th
e RG flow in the perspectives of both nonequilibrium thermodynamics and ge
ometry\, we construct a holographic dual effective field theory of the coh
omological type a la Witten\, which manifests the RG flow in the level of
an effective action. This effective field theory framework allows us to in
troduce various kinds of entropy functionals\, where their monotonic behav
iors play central roles in the monotonicity of the RG flow. We discuss how
the Gibbs-type entropy functional\, the holographic entropy functional\,
the Perelman’s entropy functional\, and the Weyl anomaly are all deeply
related\, based on our holographic dual effective field theory.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/156
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ryo Suzuki (Southeast U.)
DTSTART:20240411T070000Z
DTEND:20240411T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/157
DESCRIPTION:Title: Tensionless Limit of Pure-Ramond-Ramond AdS3/CFT2\nby Ryo Suzuki (Southeast U.) as part of KIAS Strings Seminar\n\n\nAbstr
act\nThe best-studied example of AdS/CFT is the correspondence between the
superstring in AdS5 x S5 and N=4 SYM in four dimensions. Much less is kno
wn about AdS3/CFT2\, such as the details of SCFT dual to the superstring i
n AdS3 x S3 x T4 with Ramond-Ramond flux. The string theory in AdS3 x S3 x
T4 is believed to be integrable in the same sense as AdS5 x S5. Recently\
, Frolov and Sfondrini proposed Mirror TBA equations that predicts the exa
ct energy of string states. We generalized the mirror TBA for excited stat
es and studied the solutions in the tensionless limit. We found that\, des
pite non-trivial wrapping corrections caused by massless virtual particles
in the mirror\, the energy of a tensionless string is similar to the spec
trum of free particles.\n\nThis work is based on joint arXiv:2303.02120\,
2308.11576 with Alberto Brollo\, Dennis le Plat and Alessandro Sfondrini.\
n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/157
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin (USC)
DTSTART:20240315T020000Z
DTEND:20240315T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/158
DESCRIPTION:Title: High dimension operators of high dimension CFTs\
nby Nathan Benjamin (USC) as part of KIAS Strings Seminar\n\n\nAbstract\nI
will discuss universal behavior of conformal field theory (CFT) data at
high energies. In particular I will discuss universal formulas for both th
e entropy and the three-point-functions of local operators for d-dimensio
nal CFT (d>2) as a function of energy and spin\, using a technique called
thermal effective field theory. This result can be thought of as a higher-
dimensional version of Cardy's formula for 2d CFTs. I will also discuss ho
lographic interpretations of this result. Based on arXiv:2306.08031 and wo
rk to appear.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/158
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Viatcheslav Mukhanov
DTSTART:20240319T070000Z
DTEND:20240319T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/159
DESCRIPTION:Title: Resolving Singularities in Gravity\nby Viatchesl
av Mukhanov as part of KIAS Strings Seminar\n\n\nAbstract\nI will show how
the singularities in Friedmann Universe\, Kasner Universe and in Black ho
le can be easily resolved by modifying the Einstein equations at high curv
atures with implementation of the concept of limiting curvature.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/159
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi Zhang (Peking U.)
DTSTART:20240429T070000Z
DTEND:20240429T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/160
DESCRIPTION:Title: Understanding Fermionic Generalized Symmetries\n
by Yi Zhang (Peking U.) as part of KIAS Strings Seminar\n\n\nAbstract\nWe
explore new aspects of internal fermionic shifting symmetries present in p
hysical systems such as free Dirac spinors and p-form tensor-spinor fields
. We propose a novel procedure to gauge these global symmetries which also
introduces a new Stückelberg mechanism to give a mass to free fermionic
fields. Furthermore we find new magnetic fermionic symmetries in these phy
sical systems whose charged objects are disorder operators. For the case o
f a Dirac spinor we discuss a dual description where the magnetic symmetry
acts on the holonomies of a dual 2-form tensor-spinor. Further generaliza
tions such as higher-group-like structures are also discussed.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/160
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nobuyoshi Ohta (Natl. Central U.\, Taiwan & Kindai U.\, Osaka)
DTSTART:20240430T070000Z
DTEND:20240430T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/161
DESCRIPTION:Title: Quantum Improved Kerr Black Holes and Thermodynamics
\nby Nobuyoshi Ohta (Natl. Central U.\, Taiwan & Kindai U.\, Osaka) as
part of KIAS Strings Seminar\n\n\nAbstract\nThe asymptotic safety approac
h to the quantum gravity suggests that the Newton coupling depends on the
energy scale. To make connection to the black hole geometry\, we have to i
dentify the energy scale to certain length scale\, but there has not been
any principle to constrain the identification. We show that the first law
of the thermodynamics gives quite nontrivial constraint on the identificat
ion\, and this leads to interesting consequences on the expression of the
entropy and black hole geometry. The quantum improved entropy reduces to t
he Bekenstein-Hawking formula in the semi-classical limit\, and suitable c
hoice of the identification leads to the possibility of singularity resolu
tion.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/161
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Lotito (SNU)
DTSTART:20240513T070000Z
DTEND:20240513T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/162
DESCRIPTION:Title: The Weak Gravity conjecture in Perturbative String T
heory\nby Matteo Lotito (SNU) as part of KIAS Strings Seminar\n\n\nAbs
tract\nI will discuss the weak gravity conjecture (WGC) starting from the
original statement and motivation\, showing the evidence for various forms
of the conjecture in string scenarios. Connecting the WGC to other\, rela
ted\, conjectures\, I will describe the results of a recent paper (2401.14
449)\, where\, by refining details of the derivation\, we are finally able
to provide a comprehensive proof of the WGC using a string worldsheet con
struction\, albeit\, for now\, restricted to the perturbative bosonic stri
ng.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/162
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hee-Joong Chung (JNU)
DTSTART:20240520T070000Z
DTEND:20240520T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/163
DESCRIPTION:by Hee-Joong Chung (JNU) as part of KIAS Strings Seminar\n\nAb
stract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/163
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fedor Popov (NYU)
DTSTART:20240603T070000Z
DTEND:20240603T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/164
DESCRIPTION:Title: Holography on the Quantum Disk\nby Fedor Popov (
NYU) as part of KIAS Strings Seminar\n\n\nAbstract\nMotivated by recent st
udy of DSSYK and the non-commutative nature of its bulk dual\, we review a
nd analyze an example of a non-commutative spacetime known as the quantum
disk proposed by L. Vaksman. The quantum disk is defined as the space whos
e isometries are generated by the quantum algebra Uq(su1\,1). We review ho
w this algebra is defined and its associated group SUq(1\,1) that it gener
ates\, highlighting its non-trivial coproduct that sources bulk non-commut
ativity. We analyze the structure of holography on the quantum disk and st
udy the imprint of non-commutativity on the putative boundary dual.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/164
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongwook Ghim (RIKEN)
DTSTART:20240610T070000Z
DTEND:20240610T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/165
DESCRIPTION:Title: Digital quantum simulation for the spectroscopy of S
chwinger model\nby Dongwook Ghim (RIKEN) as part of KIAS Strings Semin
ar\n\n\nAbstract\nWe present a method for computing energy spectra in latt
ice field theory using digital quantum simulation. The method\, inspired b
y coherent imaging spectroscopy\, perturbs the vacuum with a time-oscillat
ing quench and analyzes the resulting loss in vacuum-to-vacuum probability
to identify excited levels. We apply this technique to (1+1)-dimensional
quantum electrodynamics with topological angle\, known as the Schwinger mo
del. Using a classical simulator\, we prepare the vacuum on a lattice with
the adiabatic method and apply various quenches through Suzuki-Trotter ap
proximation. The computational complexity estimation suggests the method b
e potentially efficient with early fault-tolerant quantum computers.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/165
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Hong Lee (KAIST)
DTSTART:20240617T070000Z
DTEND:20240617T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/166
DESCRIPTION:Title: Classification of simple large N SCFTs in 4d\nby
Ki-Hong Lee (KAIST) as part of KIAS Strings Seminar\n\n\nAbstract\nI will
discuss 4d N=1 SCFTs obtained at the IR fixed points of UV gauge theories
with simple gauge groups that admit the large N limit. These SCFTs are cl
assified into 38 theory classes solely based on group theory. I will intro
duce some exotic cases that exhibit dense spectra of low-lying operators a
nd compare their properties with those of holographic SCFTs. Finally\, I w
ill explore a universal aspect of these large N SCFTs inspired by the CFT
Weak Gravity Conjecture.\n\nReferences: arXiv: 2007.16165\, 2308.01717\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/166
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (Southeast U.)
DTSTART:20240708T070000Z
DTEND:20240708T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/167
DESCRIPTION:Title: Trans-series for Hofstadter Butterfly\nby Jie Gu
(Southeast U.) as part of KIAS Strings Seminar\n\n\nAbstract\nThe Harper-
Hofstadter model is an interesting 2d electron model in a square lattice w
ith a uniform and perpendicular magnetic field\, and its energy spectrum a
s a function of the magnetic field displays an intriguing pattern\, known
as the Hofstadter's butterfly\, which implies very rich non-perturbative s
tructures. Using a surprising connection with supersymmetric field theory
and topological string\, we write down a conjectural formula of the full e
nergy trans-series which includes all orders instanton corrections when th
e magnetic flux is 2\\pi/Q for natural numbers Q\, and we verify our formu
la with high precision numerical calculations.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/167
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Norton Lee (IBS)
DTSTART:20240722T070000Z
DTEND:20240722T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/168
DESCRIPTION:Title: Dimer integrable model: Hamiltonians on a chess boar
d\nby Norton Lee (IBS) as part of KIAS Strings Seminar\n\n\nAbstract\n
Dimer model\, also known as brane tiling or domino tiling\, is a study of
tessellation of an Euclidean plane. We consider a class of integrable syst
ems proposed by Goncharov and Kenyon in correspondence with the dimer mode
ls on a torus. These integrable systems are the generalization of the affi
ne A-type relativistic Toda lattice. According to the correspondence\, eve
ry dimer model defines an integrable system\, whose conserving charges can
be systematically calculated based on the perfect matching of the biparti
te graph. We will explain two ways of modifying the known dimer graph\, wh
ich generates new integrable systems. The quantization of these integrable
systems can be solved by Bethe/Gauge correspondence with co-dimensional t
wo defect introduced in 5d N=1 supersymmetric gauge theories.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/168
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martí Rosselló (Academica Sinica Taiwan)
DTSTART:20240624T070000Z
DTEND:20240624T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/169
DESCRIPTION:Title: The Giant Graviton Expansion in AdS5 x S5\nby Ma
rtí Rosselló (Academica Sinica Taiwan) as part of KIAS Strings Seminar\n
\n\nAbstract\nThe 1/2-BPS index of N=4 SYM with gauge group U(N) can be wr
itten as the large N answer times an infinite series of finite N correctio
ns. This expansion is called the giant graviton expansion. I will explain
how such an expansion arises in the bulk as a result of the localization o
f the path integral which computes the bulk 1/2-BPS index to a product of
small fluctuations of the vacuum and of the collective modes of an arbitra
ry number of maximal giant gravitons.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/169
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Peter Koroteev (UC Berkeley)
DTSTART:20240717T070000Z
DTEND:20240717T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/170
DESCRIPTION:Title: Opers\, Gauge Theories\, and Integrability\nby P
eter Koroteev (UC Berkeley) as part of KIAS Strings Seminar\n\n\nAbstract\
nI will introduce the notions of (G\,q)-opers\, where G is a simply-connec
ted complex simple Lie group\, and prove some general results about their
structure. Then I establish a one-to-one correspondence between the set of
such opers and the set of nondegenerate solutions of a system of Bethe An
satz equations as well as the so-called QQ-systems. I’ll discuss the ope
r interpretation of Seiberg-like dualities in supersymmetric quiver theori
es in three dimensions.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/170
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minkyoo Kim (CQUeST)
DTSTART:20240821T070000Z
DTEND:20240821T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/171
DESCRIPTION:Title: Black holes from Young diagrams\nby Minkyoo Kim
(CQUeST) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study heavy ope
rators of N=4 SYM. Because they have dimensions over the order of N\, thei
r correlation functions\, etc.\, are not sufficient as planar contribution
s even in the large N limit\, and nonplanar effects are important. In part
icular\, we would like to propose a holographic dual of a black hole from
heavy operators with a dimension of order N^2. These are constructed from
restricted Schur polynomials and the corresponding Young diagrams are give
n by the VKLS curve and a curve which generalizes the VKLS shape when fini
te N constraints are important. We also give some comments on the dilatati
on problem for these operators and its application.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/171
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Tong (Cambridge University)
DTSTART:20240909T070000Z
DTEND:20240909T083000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/172
DESCRIPTION:Title: Fermion-Monopole Scattering is Weird.\nby David
Tong (Cambridge University) as part of KIAS Strings Seminar\n\n\nAbstract\
nWhen chiral fermions scatter off monopoles\, strange things happen. In ma
ny situations\, including in the Standard Model\, there is an apparent par
adox because it seems impossible for scattering to be consistent with gaug
e symmetry. I’ll explain how this paradox arises and describe its resolu
tion\, in which outgoing radiation sits in a twisted sector of the Hilbert
space.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/172
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cynthia Yan
DTSTART:20241007T020000Z
DTEND:20241007T030000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/173
DESCRIPTION:Title: Exploring supersymmetric wormholes in N = 2 SYK with
chords\nby Cynthia Yan as part of KIAS Strings Seminar\n\n\nAbstract\
nA feature the N =2 supersymmetric Sachdev-Ye-Kitaev (SYK) model shares wi
th extremal black holes is an exponentially large number of ground states
that preserve supersymmetry. In fact\, the dimension of the ground state s
ubsector is a finite fraction of the total dimension of the SYK Hilbert sp
ace. This fraction has a remarkably simple bulk interpretation as the prob
ability that the zero-temperature wormhole --- a supersymmetric Einstein-R
osen bridge --- has vanishing length. Using chord techniques\, we compute
the zero-temperature Hartle-Hawking wavefunction\; the results reproduce t
he ground state count obtained from boundary index computations\, includin
g non-perturbative corrections. Along the way\, we improve the constructio
n of the super-chord Hilbert space and show that the transfer matrix of th
e empty wormhole enjoys an enhanced N = 4 supersymmetry. We also obtain
expressions for various two point functions at zero temperature. Finally\,
we find the expressions for the supercharges acting on more general wormh
oles with matter and present the superchord algebra.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/173
/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Roberts
DTSTART:20241021T070000Z
DTEND:20241021T080000Z
DTSTAMP:20260404T094554Z
UID:kias-string-seminars/174
DESCRIPTION:Title: Supersymmetric magnetic defects\nby Matthew Robe
rts as part of KIAS Strings Seminar\n\n\nAbstract\nDefect CFTs provide an
exciting new playground to study RG flows and their endpoints. After revie
wing some basics of defect CFTs\, I will present a detailed study of super
symmetric magnetic solenoid defects (also known as monodromy defects). We
will measure the response of the system to the insertion of the magnetic s
olenoid\, and in the four dimensional case will calculate new central char
ges which appear in the trace anomaly. We close by commenting on new possi
ble monotonic quantities in these new mixed dimensional systems.\n
LOCATION:https://stable.researchseminars.org/talk/kias-string-seminars/174
/
END:VEVENT
END:VCALENDAR