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BEGIN:VEVENT
SUMMARY:Dongmin Gang (APCTP)
DTSTART:20200420T080000Z
DTEND:20200420T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/1
DESCRIPTION:Title: Twisted indices in 3d-3d correspondence\nby Dongmin Gang
(APCTP) as part of KIAS Strings Seminar\n\n\nAbstract\nI will talk about 3
d-3d relation for twisted indices on general Riemann surface and its appli
cations to i) microstates counting of supersymmetric blackholes and ii) ma
thematics of Reidermeister torsion on hyperbolic 3-manifolds.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yu Nakayama (Rikkyo University)
DTSTART:20200506T080000Z
DTEND:20200506T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/2
DESCRIPTION:Title: Supersymmetric CP-violating Weyl anomaly\nby Yu Nakayama
(Rikkyo University) as part of KIAS Strings Seminar\n\n\nAbstract\nIn CP-v
iolating conformal field theories in four dimensions\, the Pontryagin dens
ity can appear in the Weyl anomaly. The Pontryagin density in the Weyl ano
maly is consistent\, but it has a peculiar feature that the parent three-p
oint function of the energy-momentum tensor can violate CP only (semi-)loc
ally.\n\nIn this talk\, I present our recent studies (with K. Nakagawa) on
the supersymmetric completion of the Pontryagin density in the Weyl anoma
ly\, where the central charge c effectively becomes a complex number. I al
so introduce a recent debate over if a Weyl fermion in four-dimensions may
or may not have the Pontryagin density in the Weyl anomaly.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongsu Bak (KIAS & U. of Seoul)
DTSTART:20200511T080000Z
DTEND:20200511T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/3
DESCRIPTION:Title: Traversable wormholes and quantum gravity lab on the tabletop
\nby Dongsu Bak (KIAS & U. of Seoul) as part of KIAS Strings Seminar\n
\n\nAbstract\nIn this talk I will introduce the traversable wormholes whic
h is related to quantum teleportation. I shall explain how the traversable
wormholes can be realized in the 2d JT gravity theory\, which is dual to
two interacting SYK quantum systems. I will show how to confirm experiment
ally the existence of the bulk wormhole with a simple set of operators in
the quantum mechanics side.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seok Kim (Seoul National University)
DTSTART:20200608T080000Z
DTEND:20200608T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/4
DESCRIPTION:Title: Microstates of AdS black holes\nby Seok Kim (Seoul Nation
al University) as part of KIAS Strings Seminar\n\n\nAbstract\nI will expla
in 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 ope
rators of the field theory at weak coupling. From the index\, one sees a f
ast growth of such states which accounts for the black hole entropy. I con
cretely illustrate this fact (and other related ideas) by numerically stud
ying the index up to U(6) gauge groups. I will then explain a yet unsolved
problem\, of explicitly constructing such operators in the cohomological
setup.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vasilis Niarchos (University of Crete)
DTSTART:20200518T080000Z
DTEND:20200518T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/5
DESCRIPTION:Title: Matching type-B conformal anomalies\nby Vasilis Niarchos
(University of Crete) as part of KIAS Strings Seminar\n\n\nAbstract\nI wil
l revisit the standard type-A and type-B classification of\nconformal anom
alies in conformal field theory. There are general arguments\nthat show th
at type-A conformal anomalies are very similar to chiral\nanomalies and th
at they match in different phases of a theory. Such\narguments do not gene
ralize to type-B anomalies\, which are expected to\ndepend on the phase of
the theory. Contrary to this general expectation\, I\nwill present a new
formal argument that can be used to prove the\nnon-perturbative matching o
f a certain class of type-B conformal anomalies\nin 4d N=2 super-conformal
field theories along the Higgs branch. In such\ncases the corresponding a
nomalies are non-trivial functions of exactly\nmarginal coupling constants
that can be computed using methods of\nsupersymmetric localisation.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Li (Beijing\, Inst. Theor. Phys.)
DTSTART:20200615T080000Z
DTEND:20200615T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/6
DESCRIPTION:Title: Quiver Yangian from crystal melting\nby Wei Li (Beijing\,
Inst. Theor. Phys.) as part of KIAS Strings Seminar\n\n\nAbstract\nThe BP
S counting of type IIA string theory on non-compact toric Calabi-Yau three
folds can be described by crystal melting. I will explain how to construct
the BPS algebras for these theories by a “bootstrap" method\, where one
solves for the algebra by demanding that it acts on the corresponding 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://researchseminars.org/talk/kias-string-seminars/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carlos Nunez (Swansea University)
DTSTART:20200525T080000Z
DTEND:20200525T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/7
DESCRIPTION:Title: Aspects of gauge-strings duality\nby Carlos Nunez (Swanse
a University) as part of KIAS Strings Seminar\n\n\nAbstract\nI will discus
s aspects of super conformal field theories in diverse dimensions. The foc
us will be on theories in four\, six and two dimensions. I will use a hol
ographic perspective to present the topics. Some aspects of Integrability
and RG flows away from the CFTs will be discussed. If time allows\, the ca
se of super conformal quantum mechanics will be addressed. This talk is ba
sed on papers I published in the last year.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Toldo (Ecole Polytechnique)
DTSTART:20200629T080000Z
DTEND:20200629T090000Z
DTSTAMP:20260422T225845Z
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\nAb
stract\nIn this talk I will review recent progress on the microstate count
ing for rotating black holes in Anti-de Sitter (AdS) spacetime. I will foc
us mostly on the gravitational part. I will review the known supersymmetri
c AdS solutions and I will describe how to construct two classes of new BP
S black holes in theories of four dimensional supergravity with uplift to
M-theory. I will describe their physical properties including their conser
ved charges and their entropy function. I will then review the state-of-th
e-art concerning their microstate counting via supersymmetric localization
.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nakwoo Kim (Kyung Hee University)
DTSTART:20200601T080000Z
DTEND:20200601T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/9
DESCRIPTION:Title: Updates on Precision Holography\nby Nakwoo Kim (Kyung Hee
University) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study super
gravity BPS equations which correspond to mass-deformation of some represe
ntative 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 point in
D=5. For these gauge theories the free energy with mass terms for matter
multiplets is calculable in large-N limit using supersymmetric localizatio
n technique. We suggest a perturbative method to solve the supergravity eq
uations. For the dual of mass-deformed ABJM model we reproduce the known e
xact solutions. For the mass-deformed Brandhuber-Oz theory our method give
s 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://researchseminars.org/talk/kias-string-seminars/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seyed Morteza Hosseini (IPMU)
DTSTART:20200706T080000Z
DTEND:20200706T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/10
DESCRIPTION:Title: Anomalies\, Black strings and the charged Cardy formula\
nby Seyed Morteza Hosseini (IPMU) as part of KIAS Strings Seminar\n\n\nAbs
tract\nWe derive the general anomaly polynomial for a class of two-dimensi
onal CFTs arising as twisted compactifications of a higher-dimensional the
ory on compact manifolds\, including the contribution of its isometries. W
e then use the result to perform a counting of microstates for dyonic rota
ting supersymmetric black strings in AdS(5) x S^5 and AdS(7) x S^4. We exp
licitly construct these solutions by uplifting a class of four-dimensional
rotating black holes. We provide a microscopic explanation of the entropy
of such black holes by using a charged version of the Cardy formula.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andy O'Bannon (U. of Southampton)
DTSTART:20200713T080000Z
DTEND:20200713T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/11
DESCRIPTION:Title: Central charges of two-dimensional boundaries and defects\nby Andy O'Bannon (U. of Southampton) as part of KIAS Strings Seminar\n\
n\nAbstract\nIn a 2d conformal field theory (CFT) the central charge is de
fined from the Virasoro algebra. Crucially\, the central charge obeys the
c-theorem\, a powerful\, universal\, non-perturbative constraint: the cent
ral charge must decrease under renormalization group flows. The central ch
arge appears in many other places too\, such as stress-tensor two-point fu
nctions\, thermal entropy\, entanglement entropy\, and so on. All of these
indicate that the central charge counts CFT degrees of freedom. However\,
what happens with a 2d boundary of a 3d CFT\, or a 2d conformal defect in
a higher-dimensional CFT? Generically in these cases no Virasoro algebra
is present. Can we still define a central charge? If so\, in what quantiti
es does it appear? Can we prove a c-theorem? These questions may be crucia
l 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 open ques
tions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noppadol Mekareeya (Milano Bicocca)
DTSTART:20200810T080000Z
DTEND:20200810T090000Z
DTSTAMP:20260422T225845Z
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\nA
bstract\nA local SL(2\,Z) transformation on the Type IIB brane configurati
on gives rise to an interesting class of 3d superconformal field theories\
, known as the S-fold SCFTs. One of the interesting features of such a the
ory is that\, in general\, it does not admit a conventional Lagrangian des
cription. Nevertheless\, it can be described by a quiver diagram with a bu
ilding block being an SCFT known as the T(U(N)) theory. In this talk\, we
discuss various interesting properties of the S-fold theories\, including
supersymmetry enhancement in the infrared as well as several interesting d
ualities. This talk will have a different emphasis than previous talks wi
th the similar title and abstract.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sara Pasquetti (Milano Bicocca)
DTSTART:20200803T080000Z
DTEND:20200803T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/13
DESCRIPTION:Title: Free field correlators\, kernel functions and 4d mirror symm
etry\nby Sara Pasquetti (Milano Bicocca) as part of KIAS Strings Semin
ar\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 related
by a new type of IR dualities which are very similar to 3d N=4 mirror dua
lities.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junya Yagi (Perimeter Institute)
DTSTART:20200817T080000Z
DTEND:20200817T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/14
DESCRIPTION:Title: Wilson-'t Hooft lines as transfer matrices\nby Junya Yag
i (Perimeter Institute) as part of KIAS Strings Seminar\n\n\nAbstract\nSup
ersymmetric gauge theories in four dimensions have various interrelated co
nnections to quantum integrable systems. I will present a new corresponden
ce which identifies Wilson-'t Hooft lines in N=2 circular quiver theories
with transfer matrices of trigonometric systems. I will explain how this
correspondence is related to Costello's 4d Chern-Simons theory and other s
imilar correspondences. This is based on my joint work with Kazunobu Maru
yoshi and Toshihiro Ota.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matti Jarvinen (APCTP)
DTSTART:20200928T080000Z
DTEND:20200928T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/15
DESCRIPTION:Title: Holographic Dense QCD and Neutron Stars\nby Matti Jarvin
en (APCTP) as part of KIAS Strings Seminar\n\n\nAbstract\nGauge/gravity du
ality can be used to study QCD at high densities and low temperatures wher
e many other theoretical tools do not work and uncertainties are therefore
large. I review recent progress on this topic\, including modeling of bot
h the nuclear and the quark matter phases\, which may appear in neutron st
ar cores and neutron star mergers. Combining predictions from gauge/gravit
y 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 discuss ap
plications to analysis of isolated neutron stars\, to transport in dense q
uark matter\, and to simulations of binary neutron star mergers.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lavneet Janagal (KIAS)
DTSTART:20201012T080000Z
DTEND:20201012T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/16
DESCRIPTION:Title: CANCELLED\nby Lavneet Janagal (KIAS) as part of KIAS Str
ings Seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthias Gaberdiel (ETH Zurich)
DTSTART:20201102T080000Z
DTEND:20201102T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/17
DESCRIPTION:Title: An exact AdS/CFT duality\nby Matthias Gaberdiel (ETH Zur
ich) as part of KIAS Strings Seminar\n\n\nAbstract\nString theory on 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 backgroun
d can be described in terms of a solvable world-sheet theory. This allows
one to compute the complete single-string spacetime spectrum and thereby d
emonstrate that it agrees with that of the symmetric orbifold of T4. Furth
ermore\, the structure of the symmetric orbifold correlators can be reprod
uced from the world-sheet perspective.\n
LOCATION:https://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:20260422T225845Z
UID:kias-string-seminars/18
DESCRIPTION:Title: Why deep networks generalize\nby Robert de Mello Koch (S
outh China Normal U. and Witwatersrand U) as part of KIAS Strings Seminar\
n\n\nAbstract\nTraining a deep network involves applying an algorithm whic
h fixes the parameters of the network. The performance of the trained deep
network is evaluated by studying the trained network's performance on uns
een test data. The difference between how the network performs on the trai
ning data and on unseen data defines a generalization error. Networks that
perform as well on unseen data as they did on training data\, have a smal
l generalization error.\n\nWe have definite expectations for the size of t
he generalization error\, based essentially on common sense. If the traini
ng data set is much smaller than the number of parameters in the network\,
training can fit any data perfectly\, so that errors and noise are captur
ed during training. Typical deeps network applications use deep networks w
ith hundreds of millions of parameters\, trained using data sets with tens
of thousands of parameters. Clearly then\, we are squarely in the regime
of large generalization errors. Remarkably however\, for typical deep lear
ning applications\, the generalization error is small. This begs the quest
ion: why do deep nets generalize?\n\nIn this talk we develop parallels bet
ween deep learning and the renormalization group to explain why deep netwo
rks generalize.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Herzog (King's College London)
DTSTART:20201109T053000Z
DTEND:20201109T063000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/19
DESCRIPTION:Title: Tractable models of boundary conformal field theory: The cas
e of O($N$) $\\phi^6$ theory in three dimensions\nby Christopher Herzo
g (King's College London) as part of KIAS Strings Seminar\n\n\nAbstract\nI
present a study of O($N$) $\\phi^6$ theory in three dimensions with a bou
ndary.\nIn the large $N$ limit\, the theory is approximately conformal. Tu
ning an approximately marginal coupling drives the theory into different p
hases. This model further allows a calculation of the boundary contributio
n to the anomaly in the trace of the stress tensor. Based on 2005.07863.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:R Loganayagam (ICTS-TIFR\, Bengaluru)
DTSTART:20201116T080000Z
DTEND:20201116T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/20
DESCRIPTION:Title: Interacting Hawking Radiation and Open QFTs\nby R Logana
yagam (ICTS-TIFR\, Bengaluru) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nIn this talk\, I will outline some of the recent developments in AdS/CF
T which allow us to study open quantum field theories using holographic me
thods. More precisely\, I will consider a quantum field theory (the system
) coupled to a holographic field theory at finite temperature (the environ
ment). The aim here is to integrate out the holographic environment with a
n aim of obtaining an effective dynamics for the resulting open quantum fi
eld theory. This is done using semiclassical gravitational Schwinger-Keldy
sh saddle geometries obtained by complexifying black hole spacetimes. In
addition to shedding light on open quantum systems coupled to strongly co
rrelated thermal environments\, these results also capture both the dissip
ative physics of black hole quasinormal modes\, as well as that of the flu
ctuations encoded in outgoing Hawking quanta\, and interactions between th
em.\n\nThis talk will be based on https://arxiv.org/abs/2004.02888 as well
as some upcoming work.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Wong (Fudan University)
DTSTART:20201130T080000Z
DTEND:20201130T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/21
DESCRIPTION:Title: Entanglement entropy and edge modes in topological string th
eory\nby Gabriel Wong (Fudan University) as part of KIAS Strings Semin
ar\n\n\nAbstract\nThe Ryu Takayanagi formula identifies the area of bounda
ry anchored extremal surfaces in AdS with the entanglement entropy of the
boundary CFT. However the bulk microstate interpretation of the extremal a
rea remains mysterious. Progress along this direction requires understand
ing how to define entanglement entropy in the bulk closed string theory.
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 Vafa duali
ty. We give a self consistent factorization of the closed string Hilbert
space which leads to string edge modes transforming under a q-deformed su
rface symmetry group. Compatibility with this symmetry requires a q-de
formed definition of entanglement entropy. Using the topological vertex
formalism\, we define the Hartle Hawking state for the resolved conifold
and compute its q-deformed entropy directly from the closed string reduced
density matrix. We find a match with a target space replica calculation
using the proposal of Susskind and Uglum. We then apply the Gopakumar V
afa duality to reproduce the closed string entropy from Chern Simons theo
ry using the un-deformed definition of entanglement entropy. Finally we
relate non local aspects of our factorization map to analogous phenomenon
recently found in JT gravity.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony (Weizmann)
DTSTART:20201208T080000Z
DTEND:20201208T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/22
DESCRIPTION:Title: A derivation of AdS/CFT for vector models\nby Ofer Aharo
ny (Weizmann) as part of KIAS Strings Seminar\n\n\nAbstract\nAfter discuss
ing what it means to derive the AdS/CFT correspondence\, I will describe o
ur attempts (in collaboration with Shai Chester and Erez Urbach\, 2011.063
28) to make this correspondence explicit in the simplest case of the O(N)
vector model. We explicitly rewrite the path integral for the free or crit
ical O(N) (or U(N)) bosonic vector models in d space-time dimensions as a
path integral over fields (including massless high-spin fields) living on
(d+1)-dimensional anti-de Sitter space. Inspired by de Mello Koch\, Jevick
i\, Suzuki and Yoon and earlier work\, we first rewrite the vector models
in terms of bi-local fields\, then expand these fields in eigenmodes of th
e conformal group\, and finally map these eigenmodes to those of fields 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 presumably equiv
alent in the large N limit to Vasiliev's classical high-spin gravity theor
y (with some specific gauge-fixing to a fixed background)\, but which 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 theories\,
where extra constraints on products of bulk fields need to be taken into a
ccount.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takuya Okuda (University of Tokyo)
DTSTART:20201214T080000Z
DTEND:20201214T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/23
DESCRIPTION:Title: Janus interface entropy and Calabi's diastasis in four-dimen
sional N=2 superconformal field theories\nby Takuya Okuda (University
of Tokyo) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study the entr
opy associated with the Janus interface in a 4d N=2 superconformal field t
heory. With the entropy defined as the interface contribution to an entang
lement entropy we show\, under mild assumptions\, that the Janus interface
entropy is proportional to the geometric quantity called Calabi's diastas
is on the space of N=2 marginal couplings\, confirming an earlier conjectu
re by two of the authors and generalizing a similar result in two dimensio
ns. Our method is based on a CFT consideration that makes use of the Casin
i-Huerta-Myers conformal map from the flat space to the round sphere.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi-Nan Wang (Oxford)
DTSTART:20210111T080000Z
DTEND:20210111T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/24
DESCRIPTION:Title: 5d and 4d SCFTs from canonical threefold singularities\n
by Yi-Nan Wang (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nIn
this talk\, I am going to investigate pairs of SCFTs associated to a canon
ical threefold singularity\, which consists of: (1) a 5d N=1 SCFT from M-t
heory (2) a 4d N=2 SCFT from IIB superstring theory. Interestingly\, the C
oulomb and Higgs branches of these theories can be studied by the resoluti
on 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 theori
es and also various theories associated to terminal singularities. For the
latter case\, they seem to describe either a free theory or the discrete
gauging of a free theory.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pietro Longhi (ETH Zurich)
DTSTART:20210201T080000Z
DTEND:20210201T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/25
DESCRIPTION:Title: (Beyond) BPS counting with Exponential Networks\nby Piet
ro Longhi (ETH Zurich) as part of KIAS Strings Seminar\n\n\nAbstract\nThis
talk is an introductory overview of the framework of exponential networks
\, its applications to counting BPS states in M theory compactifications\,
and related problems in enumerative geometry. \nAfter reviewing the relev
ant background and motivations\, I will present the key definitions and sh
ow some applications. Time permitting\, I will discuss the relation to qui
vers and wall-crossing invariants\, and a recent application to BPS counti
ng on the local Hirzebruch surface F_0.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tadashi Okazaki (Durham)
DTSTART:20210322T080000Z
DTEND:20210322T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/26
DESCRIPTION:Title: Operator Algebras in 3d N=4 gauge theories and their applica
tions\nby Tadashi Okazaki (Durham) as part of KIAS Strings Seminar\n\n
\nAbstract\nThe algebras emerging from three-dimensional N=4 supersymmetri
c gauge theories allow for new approaches to quantum field theories\, incl
uding computations of physical observables and rigorous formulation of du
alities. I will discuss the algebraic formulas of sphere partition functio
ns and correlation functions in terms of the twisted traces over the Verma
modules of the quantized Coulomb and Higgs branch algebras based on my wo
rk 1911.11126 with Davide Gaiotto and stringent tests of dualities of half
-BPS boundary conditions via half-indices based on my works 1905.07425\, 2
010.13177.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leopoldo A. Pando Zayas (Michigan)
DTSTART:20210329T010000Z
DTEND:20210329T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/27
DESCRIPTION:Title: AdS BH entropy and the Kerr/CFT correspondence\nby Leopo
ldo A. Pando Zayas (Michigan) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nThe Bekenstein-Hawking entropy of asymptotically Anti-de-Sitter black h
oles in dimensions 4\, 5\, 6 and 7 has recently been given an statistical
interpretation in the context of the AdS/CFT correspondence. The explanati
ons provided make use of intricate knowledge of the dual field theories in
3\, 4\, 5 and 6 dimensions. It is expected on accounts of the renormaliza
tion flow paradigm that such a universal aspect as the Bekenstein-Hawking
entropy might admit an explanation solely based on low-energy dynamics. We
point that the Kerr/CFT correspondence realizes this expectation by provi
ding a unified statistical interpretation for the entropy of all black ho
les and discuss some of the implications of this state of affairs.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dan Xie (Tsinghua)
DTSTART:20210315T080000Z
DTEND:20210315T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/28
DESCRIPTION:Title: Mixed hodge module and N=2 Coulomb branch solution\nby D
an Xie (Tsinghua) as part of KIAS Strings Seminar\n\n\nAbstract\nSeiberg-W
itten (SW) geometry has been the key to understand the Coulomb branch of 4
d N=2 theories. While many SW geometries have been found\, the understandi
ng of Coulomb branch physics is still difficult due to following reasons:
a) The difficulty in extracting electric-magnetic charge and flavor charge
\; b) The difficulty in finding the physics at special vacua\; c) The diff
iculty of finding SW differential. We show that new mathematical structur
e called mixed hodge module will help us solve above problems.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Diego Rodriguez Gomez (Oviedo)
DTSTART:20210308T080000Z
DTEND:20210308T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/29
DESCRIPTION:Title: Correlation functions in finite temperature CFT and black ho
le singularities\nby Diego Rodriguez Gomez (Oviedo) as part of KIAS St
rings Seminar\n\n\nAbstract\nWe compute thermal 2-point correlation functi
ons in the black brane AdS5 background dual to 4d CFT’s at finite temper
ature for operators of large scaling dimension. We find a formula that mat
ches the expected structure the OPE. It exhibits an exponentiation propert
y\, whose origin we explain. We also compute the first correction to the t
wo-point function due to graviton emission\, which encodes the time travel
to the black hole singularity.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210323T053000Z
DTEND:20210323T070000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/30
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 2/3\nb
y Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Seminar\n
\n\nAbstract\nD-instantons give non-perturbative contribution to string th
eory amplitudes which can be computed using world-sheet techniques. Howeve
r the integrals that appear in this computation often have\ndivergences fr
om corners of the moduli spaces which cannot be tamed by the usual procedu
re of analytic continuation. We show how using insights from string field
theory we can extract finite unambiguous results from these apparently div
ergent integrals.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210322T053000Z
DTEND:20210322T070000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/31
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 1/3\nb
y Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Seminar\n
\n\nAbstract\nD-instantons give non-perturbative contribution to string th
eory amplitudes which can be computed using world-sheet techniques. Howeve
r the integrals that appear in this computation often have\ndivergences fr
om corners of the moduli spaces which cannot be tamed by the usual procedu
re of analytic continuation. We show how using insights from string field
theory we can extract finite unambiguous results from these apparently div
ergent integrals.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen (Harish-Chandra Res. Inst.)
DTSTART:20210324T053000Z
DTEND:20210324T070000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/32
DESCRIPTION:Title: D-instanton amplitudes in string theory - Lecture 3/3\nb
y Ashoke Sen (Harish-Chandra Res. Inst.) as part of KIAS Strings Seminar\n
\n\nAbstract\nD-instantons give non-perturbative contribution to string th
eory amplitudes which can be computed using world-sheet techniques. Howeve
r the integrals that appear in this computation often have\ndivergences fr
om corners of the moduli spaces which cannot be tamed by the usual procedu
re of analytic continuation. We show how using insights from string field
theory we can extract finite unambiguous results from these apparently div
ergent integrals.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Per Kraus (UCLA)
DTSTART:20210412T020000Z
DTEND:20210412T030000Z
DTSTAMP:20260422T225845Z
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 classica
l and quantum formulation of pure 3d gravity with Dirichlet boundary condi
tions. Working in the covariant phase space formalism I will show how to o
btain the classical Poisson bracket algebra of observables in this theory\
, and then discuss quantization\, comparing low order results to expectati
ons based on TTbar deformed CFTs.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Prem Kumar (Swansea University)
DTSTART:20210510T080000Z
DTEND:20210510T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/34
DESCRIPTION:Title: Islands and Hawking radiation correlations of evaporating bl
ack holes\nby Prem Kumar (Swansea University) as part of KIAS Strings
Seminar\n\n\nAbstract\nWe consider the effect of shockwaves on the entang
lement structure of black holes. We examine the correlations in generic
subsets of the Hawking radiation emitted by evaporating black holes follow
ing the shockwave insertion and find a zoo of competing island saddle poin
ts for the associated entanglement entropies. By computing the mutual info
rmation between early and late modes we establish long range correlations
in the Hawking radiation.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Davide Cassani (Padova)
DTSTART:20210419T080000Z
DTEND:20210419T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/35
DESCRIPTION:Title: Effective field theory for the 4d N=1 index on the second sh
eet\nby Davide Cassani (Padova) as part of KIAS Strings Seminar\n\n\nA
bstract\nThe counting of BPS states in four-dimensional N=1 theories has a
ttracted a lot of attention in recent years. A generating function (with s
igns) for this counting problem is the supersymmetric index. This has bran
ch cuts and hence several Cardy-like limits\, which are analogous to high-
temperature limits. Particularly interesting is the second sheet\, which h
as been shown to capture the microstates and phases of supersymmetric blac
k holes in AdS_5. The talk will present a manifestly supersymmetric 3d eff
ective 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 exponentia
lly small corrections\, the index is then completely characterized by a un
iversal\, finite series made of 3d local terms\, the supersymmetric Casimi
r energy and a very simple logarithmic term. These will be determined in p
art explicitly and in part conjecturally.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Jinwoo Kang (KAIST)
DTSTART:20210503T080000Z
DTEND:20210503T090000Z
DTSTAMP:20260422T225845Z
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 compactification to
study the strongly coupled regime of the lower-dimensional theories via hi
gher-dimensional theories. In particular\, I will present 4d N=2 superconf
ormal field theories (of class S) from two 6d origins: (1\,0) theory on a
torus and (2\,0) theory on a punctured Riemann surface. I will algorithmic
ally describe how to get the 4d data from 6d (1\,0) SCFTs via F-theory wit
h geometric-engineering and explain its physical significance.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeff Murugan (University of Cape Town)
DTSTART:20210426T080000Z
DTEND:20210426T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/37
DESCRIPTION:Title: A 4-dimensional duality web\nby Jeff Murugan (University
of Cape Town) as part of KIAS Strings Seminar\n\n\nAbstract\nI will discu
ss the construction of a web of non-supersymmetric dualities in four space
time dimensions for theories with theta and Maxwell terms. Our constructio
n mirrors the recipe used in (2+1)-dimensions to demonstrate a similar dua
lity web for theories with Chern-Simons terms and points to a multi-dimens
ional duality web that connects low energy theories in 4-\, 3- and 2-space
time dimensions. Time permitting\, I will discuss some applications to the
physics of 3d topological insulators.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeong-Hyuck Park (Sogang University)
DTSTART:20210517T080000Z
DTEND:20210517T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/38
DESCRIPTION:Title: String Theory and Non-Riemannian Geometry\nby Jeong-Hyuc
k Park (Sogang University) as part of KIAS Strings Seminar\n\n\nAbstract\n
Postulating O(D\,D) symmetry as the fundamental principle\, General Relati
vity including the Einstein equations can be unambiguously augmented to an
other pure gravity\, namely Double Field Theory. Formulated a priori in t
erms of O(D\,D) covariant variables\, Double Field Theory and also associ
ated doubled worldsheet action not only geometrize the whole closed strin
g massless sector which is conventionally Riemannian\, but also describe v
arious non-Riemannian geometries as novel string backgrounds.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Benini (SISSA)
DTSTART:20210531T080000Z
DTEND:20210531T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/39
DESCRIPTION:Title: Superconformal Index and Gravitational Path Integral\nby
Francesco Benini (SISSA) as part of KIAS Strings Seminar\n\n\nAbstract\nA
dS/CFT provides a consistent non-perturbative definition of quantum\ngravi
ty in asymptotically AdS spacetimes. Black holes should\ncorrespond to ens
embles of states in the boundary field theory. By\nperforming a careful an
alysis of the superconformal index of 4d N=4\nSU(N) Super-Yang-Mills theor
y\, with the help of a Bethe Ansatz type\nformula\, we are able to exactly
reproduce the Bekenstein-Hawking\nentropy of BPS black holes in AdS5 x S5
. The large N limit exhibits\nmany competing contributions\, that we are a
ble to identify with\ncomplex saddles of the (putative) gravitational path
-integral. Along\nthe way we propose a necessary condition for complex sad
dles to\ncontribute\, based on the size of their non-perturbative correcti
ons.\nSuch a prescription exactly matches the field theory analysis.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210622T080000Z
DTEND:20210622T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/40
DESCRIPTION:Title: [Date Changed] The String dual to Free $\\mathcal{N}=4$ Supe
r Yang-Mills theory\nby Rajesh Gopakumar (ICTS) as part of KIAS String
s Seminar\n\n\nAbstract\nIn this talk we will discuss a proposal for a wor
ldsheet 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 dimens
ions. The worldsheet theory is a natural generalisation of the twistorial
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 worldshe
et theory contains spectrally flowed representations. We propose that in e
ach such sector only a finite set of generalised zero modes (‘wedge mode
s’) are physical. We show that after imposing the appropriate residual g
auge conditions\, this worldsheet description reproduces precisely the spe
ctrum of the planar gauge theory. The resulting physical picture is a cova
riant version of the BMN light-cone string\, now with a finite number of t
wistorial string bit constituents of an essentially topological worldsheet
.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seung-Joo Lee (IBS)
DTSTART:20210607T080000Z
DTEND:20210607T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/41
DESCRIPTION:Title: Tensionless Strings and the Swampland in Four Dimensions
\nby Seung-Joo Lee (IBS) as part of KIAS Strings Seminar\n\n\nAbstract\nTh
e aim of this talk is to report on recent progress towards understanding h
ow string theory realizes general conjectures on the nature of quantum gra
vity\, focusing on four-dimensional theories with minimal supersymmetry. S
pecifically we will address two famous conjectures: the Distance Conjectur
e and the Weak Gravity Conjecture. The former claims that an infinite towe
r of states should become light near the boundary of the moduli space. Acc
ording to the Emergent String Conjecture\, this tower should correspond ei
ther to a Kaluza-Klein tower or to the excitation tower of a weakly couple
d critical string. We will first verify this within the framework of geome
tric F-theory compactifications\, by classifying infinite distance limits
in the Kahler moduli space and analyzing them including quantum correction
s. We will then argue that the string tower at weak coupling provides a su
blattice of particles fulfilling the Weak Gravity Conjecture\, at or away
from the strict infinities.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julius Grimminger (Imperial College)
DTSTART:20210524T080000Z
DTEND:20210524T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/42
DESCRIPTION:Title: Branes\, Quivers\, and the affine Grassmannian\nby Juliu
s Grimminger (Imperial College) as part of KIAS Strings Seminar\n\n\nAbstr
act\nThe affine Grassmannian of a group G is an object from geometric repr
esentation theory. We will see that it arises quite naturally when studyin
g gauge theories with 8 supercharges and the brane systems they live on. W
e will begin by reviewing the notion of Hasse diagrams\, stratification an
d transverse slices for Coulomb branches of 3d N=4 quiver theories\, and h
ow this is captured by Kraft-Procesi transitions in the brane system. We w
ill then study the affine Grassmannian from this perspective\, starting wi
th the simplest possible one where G=SL(2\,C). We will then generalise to
higher ranks and other classical groups. If there is enough time\, excepti
onal groups will be addressed.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (University of Geneva)
DTSTART:20210621T080000Z
DTEND:20210621T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/43
DESCRIPTION:Title: Resurgence and BPS invariants\nby Jie Gu (University of
Geneva) as part of KIAS Strings Seminar\n\n\nAbstract\nAsymptotic series a
re ubiquitous in physics. And the resurgence theory provides a powerful t
ool to study them. In particular the resurgence theory reveals that diffe
rent asymptotic series at different saddle points are related to each othe
r by Stokes automorphisms characterised by Stokes constants. We argue that
the Stokes constants can be treated as new invariants of the theories in
question\, and in some non-trivial examples they are integers and they can
be interpreted as counting of BPS states. We support this statement with
examples in Seiberg-Witten theory\, complex Chern-Simons theory\, and top
ological string theory. The topological string -- spectral theory (TS/ST)
correspondence plays an important in the last example.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210608T050000Z
DTEND:20210608T063000Z
DTSTAMP:20260422T225845Z
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 Strings Sem
inar\n\n\nAbstract\nIn these lectures I will try to give an accessible int
roduction to a program to derive the AdS/CFT duality starting from the ten
sionless limit of the string theory. We will focus on the case of $AdS_3/C
FT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\times T^4
$ has one unit of NS-NS flux and is dual to the free symmetric orbifold th
eory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in this lim
it is described by a twistorial free field sigma model. We will discuss h
ow the perturbative string spectrum matches with those of the single cycl
e operators on the orbifold. Then we go on to argue why correlation functi
ons of physical operators manifestly match with those of the orbifold theo
ry. This follows from a subtle but crucial property of localisation of the
string correlators on the moduli space. Time permitting I will also discu
ss some implications of the duality for the physics of black holes in this
background.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210609T050000Z
DTEND:20210609T063000Z
DTSTAMP:20260422T225845Z
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 Strings Sem
inar\n\n\nAbstract\nIn these lectures I will try to give an accessible int
roduction to a program to derive the AdS/CFT duality starting from the ten
sionless limit of the string theory. We will focus on the case of $AdS_3/C
FT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\times T^4
$ has one unit of NS-NS flux and is dual to the free symmetric orbifold th
eory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in this lim
it is described by a twistorial free field sigma model. We will discuss h
ow the perturbative string spectrum matches with those of the single cycl
e operators on the orbifold. Then we go on to argue why correlation functi
ons of physical operators manifestly match with those of the orbifold theo
ry. This follows from a subtle but crucial property of localisation of the
string correlators on the moduli space. Time permitting I will also discu
ss some implications of the duality for the physics of black holes in this
background.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rajesh Gopakumar (ICTS)
DTSTART:20210610T050000Z
DTEND:20210610T063000Z
DTSTAMP:20260422T225845Z
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 Strings Sem
inar\n\n\nAbstract\nIn these lectures I will try to give an accessible int
roduction to a program to derive the AdS/CFT duality starting from the ten
sionless limit of the string theory. We will focus on the case of $AdS_3/C
FT_2$ where the tensionless string theory on $AdS_3 \\times S^3\\times T^4
$ has one unit of NS-NS flux and is dual to the free symmetric orbifold th
eory $(T^4)^N/S_N$ (in the large $N$ limit). The string theory in this lim
it is described by a twistorial free field sigma model. We will discuss h
ow the perturbative string spectrum matches with those of the single cycl
e operators on the orbifold. Then we go on to argue why correlation functi
ons of physical operators manifestly match with those of the orbifold theo
ry. This follows from a subtle but crucial property of localisation of the
string correlators on the moduli space. Time permitting I will also discu
ss some implications of the duality for the physics of black holes in this
background.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minsung Kim (POSTECH)
DTSTART:20210628T080000Z
DTEND:20210628T090000Z
DTSTAMP:20260422T225845Z
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 spectra of
large class of 5d and 6d supersymmetric quantum field theories are comput
ed via blowup equation. We generalize the blowup formula to calculate the
partition function of 5d/6d field theories on Omega-background in presence
of Wilson loop/Wilson surface operators. We test this approach by calcula
ting Wilson loop partition functions in various 5d/6d field theories and c
omparing them with known results and expected dualities.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yutaka Yoshida (Tokyo Inst. of Technology)
DTSTART:20210712T080000Z
DTEND:20210712T090000Z
DTSTAMP:20260422T225845Z
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 Technology) as
part of KIAS Strings Seminar\n\n\nAbstract\nWe evaluate the vacuum expect
ation values of half-BPS 't Hooft operators in supersymmetric gauge theori
es with eight supercharges in three\, four\, and five dimensions in terms
of supersymmetric localization. In localization formulas\, there exist non
-perturbative contributions from the moduli of Dirac monopoles screened by
't Hooft-Polyakov monopoles\, called monopole bubbling effects (a.k.a. mo
nopole screening effects). By introducing orientifolds\, we generalize the
brane construction of monopole bubbling effects for SU(N) gauge theories
to SO(N) and USp(N) gauge theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junho Hong (KU Leuven)
DTSTART:20210927T080000Z
DTEND:20210927T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/49
DESCRIPTION:Title: The topologically twisted index of N=4 SU(N) SYM theory and
a black hole Farey tail\nby Junho Hong (KU Leuven) as part of KIAS Str
ings Seminar\n\n\nAbstract\nIn this talk\, we investigate the large-N asym
ptotics of the topologically twisted index of N=4 SU(N) Super-Yang-Mills (
SYM) theory on T2×S2 and provide its holographic interpretation based on
the black hole Farey tail. In the field theory side\, we use the Bethe-Ans
atz (BA) formula\, which gives the twisted index of N=4 SYM theory as a di
screte sum over Bethe vacua\, to compute the large-N asymptotics of the tw
isted 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 comput
e the regularized on-shell actions. The gravitational partition function g
iven in terms of these regularized on-shell actions is then compared with
a canonical partition function derived from the twisted index by the inver
se Laplace transform\, in the large-N limit. This extends the previous mic
rostate counting of an AdS5 black string by the twisted index and thereby
improves holographic understanding of the twisted index. Lastly\, we discu
ss future research directions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Bertolini (SISSA\, Trieste)
DTSTART:20210915T080000Z
DTEND:20210915T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/50
DESCRIPTION:Title: The Octagon and the Non-Supersymmetric String Landscape\
nby Matteo Bertolini (SISSA\, Trieste) as part of KIAS Strings Seminar\n\n
\nAbstract\nA long standing open question in the context of the gauge/grav
ity correspondence - more specifically in models of D-branes at Calabi-Yau
singularities - regards the possibility of describing holographically su
persymmetric gauge theories that dynamically break supersymmetry in stable
vacua. In this talk I will present an orientifold of a Calabi-Yau singu
larity\, the Octagon\, which admits configurations of D-branes with this p
roperty. This model represents the first such instance within the gauge/gr
avity duality and may find interesting applications therein. I will also e
xplain to what extent this result might be relevant for the string theory
landscape and the swampland program.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Couzens (Utrecht University)
DTSTART:20210913T080000Z
DTEND:20210913T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/51
DESCRIPTION:Title: Black string near-horizons\, 2d quiver SCFTs and fractional
branes\nby Christopher Couzens (Utrecht University) as part of KIAS St
rings Seminar\n\n\nAbstract\nWe will discuss a recently classified class o
f (0\,4) AdS3 solutions in massless type IIA supergravity and their dual C
FTs. The solutions depend on solving a Laplace-like equation with a flux s
ource term. We will focus on a solution of this master equation where the
flux source term arises due to the presence of fractional branes preservin
g conformality. We give a candidate dual quiver 2d CFT by studying the bra
ne construction and the quantized strings of the setup.\nThis talk is base
d on recent work with Y. Lozano\, N. Petri\, and S. Vandoren.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenzo Di Pietro (Trieste University)
DTSTART:20211018T080000Z
DTEND:20211018T090000Z
DTSTAMP:20260422T225845Z
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\nAbstr
act\nThe seminar is based on: https://arxiv.org/abs/2107.00342. I will dis
cuss new evidence -from the 4+epsilon expansion- of the existence of inter
acting CFTs in 5d that provide UV completions of non-abelian gauge theorie
s. The method used is Padé-Borel resummation and extrapolation of the fiv
e-loop pertubative results.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Irene Valenzuela (Harvard University)
DTSTART:20211026T010000Z
DTEND:20211026T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/53
DESCRIPTION:Title: Non-Invertible Global Symmetries and Completeness of the Spe
ctrum in the Swampland Program\nby Irene Valenzuela (Harvard Universit
y) as part of KIAS Strings Seminar\n\n\nAbstract\nIt is widely believed th
at consistent theories of quantum gravity satisfy two basic kinematic cons
traints: they are free from any global symmetry\, and they contain a compl
ete spectrum of gauge charges. For compact\, abelian gauge groups\, comple
teness follows from the absence of a 1-form global symmetry. However\, thi
s correspondence breaks down for more general gauge groups\, where the bre
aking of the 1-form symmetry is insufficient to guarantee a complete spect
rum. We show that the correspondence may be restored by broadening our not
ion of symmetry to include non-invertible topological operators\, and prov
e that their absence is sufficient to guarantee a complete spectrum for an
y compact\, possibly disconnected gauge group. In addition\, we prove an a
nalogous statement regarding the completeness of twist vortices: codimensi
on-2 objects defined by a discrete holonomy around their worldvolume\, suc
h as cosmic strings in four dimensions. I will also discuss how this corre
spondence is modified in more general contexts\, including e.g. Chern-Simo
ns terms.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero (Harvard University)
DTSTART:20211005T040000Z
DTEND:20211005T050000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/54
DESCRIPTION:Title: The anomaly that was not meant IIB\nby Miguel Montero (H
arvard University) as part of KIAS Strings Seminar\n\n\nAbstract\nType IIB
supergravity famously has a discrete duality group\, which is an exact sy
mmetry of the full type IIB string theory. This symmetry has potential qua
ntum anomalies\, which could render the theory inconsistent. In this talk
I will describe how we computed these anomalies in recent work\, and 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 cancell
ations that depend on the precise details of the IIB supergravity spectrum
. I will also describe alternative ways to cancel this anomaly\, presentin
g variant versions of IIB string theory which have the same IIB supergravi
ty as the low-energy limit\, but which differ at the nonperturbative level
. These theories may or may not be in the Swampland.\n\n*Please note the u
nusual time of the seminar -comment added by organizer\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Murat Kologlu (Oxford)
DTSTART:20211101T080000Z
DTEND:20211101T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/55
DESCRIPTION:Title: Factorization in Quantum Gravity and Supersymmetry\nby M
urat Kologlu (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nOne o
f the lasting puzzles in quantum gravity is whether the holographic descri
ption of a gravitational system is a single quantum mechanical theory or t
he disorder average of many. In the latter case\, multiple copies of bound
ary observables do not factorize into a product\, but rather have higher m
oments. These correlations are interpreted in the bulk as due to geometrie
s involving spacetime wormholes which connect disjoint boundaries. \n\nI w
ill talk about the question of factorization and the role of wormholes for
supersymmetric observables\, specifically the supersymmetric index. Worki
ng with the Euclidean gravitational path integral\, we will start with a b
ulk prescription for computing the supersymmetric index\, which agrees wit
h the usual boundary definition. Concretely\, we will focus on the setting
of charged black holes in asymptotically flat four-dimensional N=2 ungaug
ed supergravity. In this case\, the gravitational index path integral has
an infinite family of Kerr-Newman classical saddles with different angular
velocities. However\, fermionic zero-mode fluctuations annihilate the con
tribution of each saddle except for a single BPS one which yields the expe
cted value of the index. We will then turn to non-perturbative corrections
involving spacetime wormholes\, and show that fermionic zero modes are pr
esent for all such geometries\, making their contributions vanish. This me
chanism works for both single- and multi-boundary path integrals. In parti
cular\, only disconnected geometries without wormholes contribute to the i
ndex path integral\, and the factorization puzzle that plagues the black h
ole partition function is resolved for the supersymmetric index. We will a
lso classify all other single-centered geometries that yield non-perturbat
ive contributions to the gravitational index of each boundary. Finally\, w
e will discuss implications and expectations for factorization and the sta
tus of supersymmetric ensembles in AdS/CFT in further generality. Talk bas
ed on [2107.09062] with Luca Iliesiu and Joaquin Turiaci.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin (Caltech)
DTSTART:20211012T010000Z
DTEND:20211012T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/56
DESCRIPTION:Title: Harmonic analysis of 2d CFT partition functions\nby Nath
an Benjamin (Caltech) as part of KIAS Strings Seminar\n\n\nAbstract\nI wil
l discuss applying the theory of harmonic analysis on the fundamental doma
in of SL(2\,Z) to partition functions of 2d conformal field theories. As a
n application I will decompose the partition function of c free bosons on
a Narain lattice into eigenfunctions of the Laplacians of worldsheet modul
i 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 Narain theo
ries including their ensemble averages manifest. I will also discuss apply
ing harmonic analysis to a general irrational 2d CFT and its connection wi
th gravity in AdS3. I will prove that the primary spectrum of any 2d CFT i
s fully determined by a certain subset of degeneracies. \n\n*Please be aw
are of the unusual date/time of the talk - comment added by organizer\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yosuke Imamura (Tokyo Inst. Tech.)
DTSTART:20211115T070000Z
DTEND:20211115T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/57
DESCRIPTION:Title: Finite-N superconformal index via the AdS/CFT correspondence
\nby Yosuke Imamura (Tokyo Inst. Tech.) as part of KIAS Strings Semina
r\n\n\nAbstract\nWe propose a prescription to calculate the superconformal
index of the N=4 U(N) supersymmetric Yang-Mills theory\nwith finite N on
the AdS side. The finite N corrections are included as contributions of D3
-branes wrapped around\nthree-cycles in S5\, which are calculated as the i
ndex of the gauge theories realized on the wrapped branes.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Karch (U. Texas\, Austin)
DTSTART:20211210T010000Z
DTEND:20211210T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/59
DESCRIPTION:Title: Exploring continuum quantum field theories of fracton order<
/a>\nby Andreas Karch (U. Texas\, Austin) as part of KIAS Strings Seminar\
n\n\nAbstract\nRecently discovered solvable lattice models\, known as frac
tons\, have\nforced us to rethink the very basic question of what a quantu
m field\ntheory is. In order to describe the continuum limit of fracton la
ttice\nmodels\, novel quantum field theories had to be written down that g
o\nbeyond what textbooks taught us\, exhibiting unusual features such as\n
subsystem symmetries\, UV sensitivity of IR quantities\, and broken\nrotat
ion invariance. This talk will describe several explorations of the\ninter
esting new properties these unusual field theories exhibit.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Haowu Wang (IBS CGP\, Pohang)
DTSTART:20211116T070000Z
DTEND:20211116T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/60
DESCRIPTION:Title: Recent results on Jacobi forms of lattice index\nby Haow
u Wang (IBS CGP\, Pohang) as part of KIAS Strings Seminar\n\n\nAbstract\nI
n 1985 Eichler and Zagier introduced the theory of Jacobi forms. Such form
s are holomorphic functions which are modular under SL(2\,Z) in the first
variable and quasi-periodic in the second variable. Later\, the Jacobi for
m of lattice index was defined by replacing the second variable with many
variables associated with a positive-definite lattice. Jacobi forms are an
elegant intermediate between different types of modular forms and have ma
ny applications in mathematics and physics. In this talk\, I will give a b
rief introduction to this theory and present some recent results. (1) In
1992 Wirthmüller proved that for any irreducible root system not of type
E_8 the algebra of weak Jacobi forms invariant under the Weyl group is a p
olynomial algebra. I will define the Jacobian of Jacobi forms and present
an automorphic proof of Wirthmüller's theorem. (2) Weyl invariant weak Ja
cobi forms for the exceptional root system E_8 appear in E-string theory.
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. Thi
s talk is based on joint works with Brandon Williams and with Kaiwen Sun.\
n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuji Hirono (APCTP)
DTSTART:20211206T070000Z
DTEND:20211206T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/61
DESCRIPTION:Title: Counting Nambu-Goldstone modes of higher-form global symmetr
ies\nby Yuji Hirono (APCTP) as part of KIAS Strings Seminar\n\n\nAbstr
act\nWhen continuous symmetries are spontaneously broken\, there appear\ng
apless modes called Nambu-Goldstone (NG) modes. Due to their gapless\nnatu
re\, they are important degrees of freedom at low energies.\nRecently\, a
generalized kind of symmetries\, called higher-form\nsymmetries\, have bee
n discussed\, whose charged objects are extended.\nThe analogue of the NG
theorem exists\, and photons can be regarded as\nNG modes for a spontaneou
sly broken higher-form symmetry.\nIn this talk\, I will discuss how to cou
nt the number of NG modes\nassociated with spontaneously broken symmetries
that can include\nhigher-form ones [1]. I will give a formula for the num
ber of NG\nmodes\, which is also applicable for systems without Lorentz\ni
nvariance.\n\nReference:\n[1] Y. Hidaka\, Y. Hirono\, R. Yokokura\, Phys.
Rev. Lett. 126\, 071601 (2021). [arXiv:2007.15901]\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hidenori Fukaya (Osaka University)
DTSTART:20211220T070000Z
DTEND:20211220T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/62
DESCRIPTION:Title: A physicist-friendly reformulation of the Atiyah-Patodi-Sing
er index\nby Hidenori Fukaya (Osaka University) as part of KIAS String
s Seminar\n\n\nAbstract\nThe Atiyah-Singer index theorem on a closed manif
old is well understood and appreciated in physics. On the other hand\, the
Atiyah-Patodi-Singer index\, which is an extension to a manifold with bou
ndary\, is physicist-unfriendly\, in that it is formulated with a nonlocal
boundary condition. Recently we proved that the same index as APS is obta
ined from the domain-wall fermion Dirac operator. Our theorem indicates th
at the index can be expressed without any nonlocal conditions\, in such a
physicist-friendly way that application to the lattice gauge theory is str
aightforward. The domain-wall fermion provides a natural mathematical foun
dation for understanding the bulk-edge correspondence of the anomaly inflo
w.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (Southeastern University of China)
DTSTART:20211227T070000Z
DTEND:20211227T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/63
DESCRIPTION:Title: Resurgent structure in Chern-Simons theory\nby Jie Gu (S
outheastern University of China) as part of KIAS Strings Seminar\n\n\nAbst
ract\nThe resurgence theory is a powerful technique to analyse asymptotic
series that arise in physics. We use the resurgence theory to study the Ch
ern-Simons theory with gauge group $\\mf{sl}_2$ on knot complement. We com
pute the Stokes automorphisms that relate the asymptotic series in the the
ory\, including the one from the trivial flat connection. We find surprisi
ng connection with BPS counting in 3d SCFT. We also construct a new state
integral from which all asymptotic series\, including the one for trivial
connection\, can be derived.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yifan Wang (New York University)
DTSTART:20220125T010000Z
DTEND:20220125T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/64
DESCRIPTION:Title: Bootstrapping Boundaries and Branes\nby Yifan Wang (New
York University) as part of KIAS Strings Seminar\n\n\nAbstract\nThe study
of conformal boundary conditions for two-dimensional conformal field theor
ies (CFTs) has a long history\, ranging from the description of impurities
in one-dimensional quantum chains to the formulation of D-branes in strin
g theory. Nevertheless\, the landscape of conformal boundaries is largely
unknown\, including in rational CFTs\, where the local operator data is co
mpletely determined. We initiate a systematic bootstrap study of conformal
boundaries in 2d CFTs by investigating the bootstrap equation that arises
from the open-closed consistency condition of the annulus partition funct
ion with identical boundaries. We find that this deceivingly simple bootst
rap equation\, when combined with unitarity\, leads to surprisingly strong
constraints on admissible boundary states. In particular\, we derive univ
ersal bounds on the tension (boundary entropy) of stable boundary conditio
ns\, which provide a rigorous diagnostic for potential D-brane decays. We
also find unique solutions to the bootstrap problem of stable branes in a
number of rational CFTs. Along the way\, we observe a curious connection b
etween the annulus bootstrap and the sphere packing problem\, which is a n
atural extension of previous work on the modular bootstrap. We also derive
bounds on the boundary entropy at large central charge. These potentially
have implications for end-of-the-world branes in pure gravity on AdS3.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuya Kusuki (Caltech)
DTSTART:20220222T010000Z
DTEND:20220222T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/65
DESCRIPTION:Title: Analytic Bootstrap in 2D Boundary Conformal Field Theory
\nby Yuya Kusuki (Caltech) as part of KIAS Strings Seminar\n\n\nAbstract\n
Recently\, boundary conformal field theories (BCFTs) have attracted much a
ttention 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 model. On
this background\, it would be interesting to explore the duality between
the boundary and the braneworld. \nHowever\, this seems to be a challengin
g problem. The reason is because although there has been much study of rat
ional BCFTs\, there has been comparatively little study of irrational BCFT
s\, and irrational BCFTs are expected to be the boundary duals of the bran
eworlds. For this reason\, we explore properties of boundary ingredients:
the boundary primary spectrum\, the boundary-boundary-boundary OPE coeffic
ients and the bulk-boundary OPE coefficients. For this purpose\, the confo
rmal bootstrap is extremely useful. This is the first step in providing an
understanding of BCFTs in the context of braneworld holography by using t
he conformal bootstrap. The techniques developed in this paper may be usef
ul for further investigation of irrational BCFTs.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul-Konstantin Oehlmann (Uppsala University)
DTSTART:20220221T080000Z
DTEND:20220221T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/66
DESCRIPTION:Title: Twisted Affine Algebras in F/M-theory\nby Paul-Konstanti
n Oehlmann (Uppsala University) as part of KIAS Strings Seminar\n\n\nAbstr
act\nIn this talk we discuss the geometry and physics of M/F-theory compac
tifications on torus fibered Calabi-Yau threefolds that lack a section. Su
ch geometries admit some striking novel features that are not present when
the torus fiber admits a global section: \nThe absence of a section allow
s for generalized monodromies that act on the affine extension of ADE fibe
rs\, leading to twisted affine algebras in M-theory. We discuss the effect
of such foldings and their geometry in detail and track them through a ch
ain of conifold transitions. This allows us to explain the twisted affine
algebras as the results of a 5D Higgsing\, where the representations have
non-trivial charges under the KK U(1) which relates the theory to 6D F-the
ory.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/66/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yiwen Pan (SYSU\, Guangzhou)
DTSTART:20220214T070000Z
DTEND:20220214T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/67
DESCRIPTION:Title: Exact Schur Index in Closed Form\nby Yiwen Pan (SYSU\, G
uangzhou) as part of KIAS Strings Seminar\n\n\nAbstract\nThe Schur limit o
f the 4d N=2 superconformal index encodes rich information of the SCFT\, a
nd it also plays a central role in the SCFT/VOA correspondence as it coinc
ides with the character of the associated VOA. There have been several way
s to compute this quantity\, where it is written as a contour integral\, o
r an infinite sum of group characters\, or simply a q-series. In this talk
we propose for Lagrangian theories an elementary approach to further comp
ute the contour integral form of the index and the final result takes the
form of a finite sum of products of the well-known Eisenstein series. In p
articular\, we derive a compact formula for the flavored Schur index of al
l 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 d
iscuss some applications to the non-Lagrangian Schur index\, index with no
n-local operators and modularity.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oleg Chalykh (University of Leeds)
DTSTART:20220523T080000Z
DTEND:20220523T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/68
DESCRIPTION:Title: Twisted Ruijsenaars models\nby Oleg Chalykh (University
of Leeds) as part of KIAS Strings Seminar\n\n\nAbstract\nThe quantum Ruijs
enaars model is a q-analogue of the Calogero—Moser model\, described by
n commuting partial difference operators (quantum hamiltonians) h_1\, …\
, h_n. Its trigonometric variant is closely related to Macdonald polynomia
ls and DAHAs. It turns out that for each natural number \\ell>1\, there ex
ists an integrable system whose quantum hamiltonians look\, loosely speaki
ng\, as the \\ell-th powers of h_1\, …\, h_n. I will discuss several way
s of arriving at this generalisation. In the elliptic case\, the deformati
on parameter (“twisting”) is an arbitrary \\ell-torsion point c on the
underlying elliptic curve\; when c=0 one gets precisely the \\ell-th powe
rs of h_1\, …\, h_n. The construction works for all root systems\, inclu
ding 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 Eric Rai
ns.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theodore D. Brennan (U. Chicago)
DTSTART:20220315T010000Z
DTEND:20220315T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/69
DESCRIPTION:Title: Callan Rubakov Effect and Higher Charge Monopoles\nby Th
eodore D. Brennan (U. Chicago) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nIn this talk we will discuss the interaction between magnetic monopole
s and massless fermions. In the 1980's Callan and Rubakov showed that in t
he simplest example and that fermion-monopole interactions catalyze proton
decay in GUT completions of the standard model. Here we will explain how
fermions in general representations interact with general spherically symm
etric monopoles and classify the types of symmetries that are broken: glob
al symmetries with ABJ-type anomalies.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Du Pei (Harvard CMSA)
DTSTART:20220329T010000Z
DTEND:20220329T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/70
DESCRIPTION:Title: Holomorphic CFTs and topological modular forms\nby Du Pe
i (Harvard CMSA) as part of KIAS Strings Seminar\n\n\nAbstract\nThe theory
of topological modular forms leads to many interesting constraints and pr
edictions for two-dimensional quantum field theories. In this talk\, I wil
l show that a conjecture by Segal\, Stolz and Teichner requires the consta
nt term of the partition function of a bosonic holomorphic CFTs to be divi
sible by specific integers determined by the central charge. We verify thi
s constraint in large classes of physical examples\, and rule out the exis
tence of an infinite set of "extremal CFTs"\, including those with central
charges c = 48\, 72\, 96 and 120.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sung-Soo Kim (UESTC\, Chengdu)
DTSTART:20220328T070000Z
DTEND:20220328T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/71
DESCRIPTION:Title: 6d Seiberg-Witten curves from 5-brane webs\nby Sung-Soo
Kim (UESTC\, Chengdu) as part of KIAS Strings Seminar\n\n\nAbstract\nIn th
is talk\, we discuss the construction of the Seiberg-Witten (SW) curves ba
sed on Type IIB 5-brane webs. After reviewing the construction for SW curv
es for 5d supersymmetric gauge theories\, we discuss how to generalize it
to 6d superconformal theories which can be realized on a 5-brane webs with
periodic direction. In particular\, we construct the SW curve for 6d E-st
ring 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 compli
cated. Our expression is\, however\, much simpler than the Eguchi and Saka
i’s one. We discuss equivalence between our curve and the Eguchi and Sak
ai. Finally we further generalize our construction of the SW curves to 6d
little string theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hee-Joong Chung (Jeju National University)
DTSTART:20220224T070000Z
DTEND:20220224T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/72
DESCRIPTION:Title: BPS Invariants for a Knot in Seifert Manifolds\nby Hee-J
oong Chung (Jeju National University) as part of KIAS Strings Seminar\n\n\
nAbstract\nIn this talk\, we discuss homological blocks for a knot in Seif
ert manifolds obtained from the Chern-Simons partition function with a Wil
son loop operator when the gauge group is SU(N). From the expectation valu
e of the Wilson loop operator\, we calculate the homological blocks by ana
lytically continuing the Chern-Simons level with a given representation. W
e also obtain homological blocks with the analytically continued level and
representation for a knot in the Seifert integer homology spheres.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kanghoon Lee (APCTP)
DTSTART:20220314T070000Z
DTEND:20220314T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/73
DESCRIPTION:Title: QFT from Recursions\nby Kanghoon Lee (APCTP) as part of
KIAS Strings Seminar\n\n\nAbstract\nWe discuss off-shell recursion relatio
ns for arbitrary loop-level scattering amplitudes beyond the conventional
tree-level recursion relations. We define a quantum perturbiner expansion
that includes loop corrections from the quantum effective action formalism
. Instead of using the classical equations of motion in the conventional
perturbiner method\, we exploit the Dyson–Schwinger equation to derive t
he quantum off-shell recursion relation. Furthermore\, we construct the re
cursions for computing loop-level correlation functions by replacing the c
hoice of the external source.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Byoungjoon Ahn (GIST)
DTSTART:20220418T070000Z
DTEND:20220418T080000Z
DTSTAMP:20260422T225845Z
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 ge
neral\, the non-traversability of wormholes is a consequence of the Averag
e Null Energy Condition (ANEC). Gao\, Jafferis and Wall (GJW) realized tha
t\, by coupling the two boundary theories with a relevant perturbation\, A
NEC can be violated\, and the wormhole can be made traversable in a two-si
ded BTZ black hole. We generalize the GJW results to higher-dimensional tr
aversable wormholes in the context of Rindler-AdS/CFT and show that the sa
me result can be obtained using the eikonal approximation. We also introdu
ce 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 information
that can be sent through the wormhole.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Couzens (Kyung-Hee University)
DTSTART:20220411T070000Z
DTEND:20220411T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/75
DESCRIPTION:Title: Multi charge Discs and Spindles\nby Christopher Couzens
(Kyung-Hee University) as part of KIAS Strings Seminar\n\n\nAbstract\nIn t
his talk I will discuss recent advances of the last year in understanding
black holes with disc or spindle horizons. The metrics on these discs and
spindles have non-constant curvature with orbifold singularities\, (or wor
se than orbifold singularities) and they evade the uniformization theorems
. \nDespite the singularities one obtains well-defined string/M-theory sol
utions and in certain cases all singularities in the uplifted theory are r
esolved. We will conclude with some comments on dual field theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seung-Joo Lee (IBS-CTPU)
DTSTART:20220530T070000Z
DTEND:20220530T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/76
DESCRIPTION:Title: The fate of not being minimal\nby Seung-Joo Lee (IBS-CTP
U) as part of KIAS Strings Seminar\n\n\nAbstract\nIn the context of eight-
dimensional F-theory\, we will discuss the physical interpretation of sing
ular fibers with vanishing orders (4\,6\,12) or beyond\, which are known a
s non-minimal fibers. While minimal fibers in codimension-one loci of the
base lead to vector fields valued in a Lie algebra\, non-minimal fibers do
not acquire such a clean interpretation and hence have typically been dis
carded in the literature. In this talk we will clarify the fate of non-min
imal fibers in the language of the effective physics and will put it also
into a more general context of the relevant swampland conjectures for quan
tum gravity.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuya Tanizaki (Kyoto YITP)
DTSTART:20220404T070000Z
DTEND:20220404T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/77
DESCRIPTION:Title: Semiclassical description of confinement via center vortices
and anomaly-preserving T^2 compactifications\nby Yuya Tanizaki (Kyoto
YITP) as part of KIAS Strings Seminar\n\n\nAbstract\nConfinement of 4d ga
uge theories is usually the strong-coupling problem\, and it is a difficul
t task to understand even its qualitative features. We are trying to devel
op its semiclassical understanding based on the idea of volume independenc
e or adiabatic continuity. We conjecture that the strong-coupling regime o
f many 4d gauge theories is continuously connected to the weak-coupling th
eories on small R2xT2 with the nontrivial ‘t Hooft flux. We explicitly c
onfirm the fractional theta periodicity for pure YM and chiral Lagrangian
for QCD can be derived in this small T2 regime\, which partly justifies ou
r conjecture. We also uncover why this is possible in view of anomaly-pres
ervation of this compactification.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Del Zotto (Uppsala University)
DTSTART:20220509T080000Z
DTEND:20220509T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/78
DESCRIPTION:Title: Back to Heterotic Instantons on ALE spaces: F-theory\, 2-gro
ups\, and T-duality\nby Michele Del Zotto (Uppsala University) as part
of KIAS Strings Seminar\n\n\nAbstract\nThe matching of the 2-group struct
ure constants for T-dual pairs of little string theories is a stringent co
nstraint. In this talk\, I will discuss an application to the problem of c
harting the T-dualities of Heterotic ALE instantons.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Junho Hong (KU Leuven)
DTSTART:20220620T070000Z
DTEND:20220620T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/79
DESCRIPTION:Title: Large N Topologically Twisted Indices\, Holography\, and Bla
ck Holes\nby Junho Hong (KU Leuven) as part of KIAS Strings Seminar\n\
n\nAbstract\nIn this talk\, I will present a simple closed form expression
for the topologically twisted index of the ABJM theory as a function of t
he magnetic fluxes and complexified electric chemical potentials valid at
fixed k and to all orders in the large N expansion. This in turn leads to
analytic expressions for the topologically twisted index at fixed genus in
the 't Hooft limit\, to all orders in the large λ=N/k expansion. These r
esults have important implications for holography and the microscopic entr
opy counting of supersymmetric static AdS4 black holes. I will also briefl
y discuss generalizations to other SCFTs arising from M2-branes.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ying-Hsuan Lin (Harvard)
DTSTART:20220613T070000Z
DTEND:20220613T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/80
DESCRIPTION:Title: Topological modular forms and Monstrous Moonshine\nby Yi
ng-Hsuan Lin (Harvard) as part of KIAS Strings Seminar\n\n\nAbstract\nWe u
se the theory of topological modular forms to constrain bosonic holomorphi
c CFTs\, which can be viewed as (0\,1) SCFTs with a trivial right-moving s
upersymmetric sector. A conjecture by Segal\, Stolz and Teichner requires
the constant term of the partition function to be divisible by specific in
tegers determined by the central charge. We verify this constraint in larg
e classes of physical examples\, and rule out the existence of an infinite
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 Mo
nster CFT\, and aided by Borcherds' generalized denominator formula\, we a
re further led to number-theoretic observations on the Fourier coefficient
s of the McKay-Thompson series.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20220517T010000Z
DTEND:20220517T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/81
DESCRIPTION:Title: D-instanton superpotential in string theory\nby Manki Ki
m (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\nD-instantons genera
te non-perturbative corrections to string theory amplitudes. These correct
ions are of particular importance because they encode non-perturbative eff
ects in string theory and play a prominent role in moduli stabilization. I
n this talk\, I will focus on D-instanton contributions\, more precisely D
(-1) and ED3 instanton contributions\, to the superpotential of low energy
effective theory of string compactification. Computing such contributions
is challenging\, because of the IR divergence due to zero modes of the D-
instanton and the fact that some instanton contributions are expected to b
e generated in the presence of non-trivial RR and NSNS fluxes. To compute
the D-instanton superpotential\, one must compute the one-loop determinant
around the saddle point. Due to the fact that these saddle point solution
s have zero modes\, the overall normalization of the superpotential contri
bution is ambiguous within the worldsheet formalism. I will discuss how on
e can use string field theory to regularize the amplitude to obtain an una
mbiguous answer. In part two of the talk\, I will explain that the D(-1)-i
nstanton contribution is expected to be generated in a non-trivial flux ba
ckground\, hence the direct computation of such effects is currently out o
f reach. I will show how one can use F-theory to compute the D(-1)-instant
on superpotential and argue that in the global Sen-limit the D(-1)-instant
on superpotential is absent.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Hong Lee (KAIST)
DTSTART:20220425T070000Z
DTEND:20220425T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/82
DESCRIPTION:Title: Higgs\, Coulomb and Hall-Littlewood\nby Ki-Hong Lee (KAI
ST) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study the Higgs bran
ch of class-S theories with twist lines\, by studying their 3d reduction a
nd corresponding mirror dual theories (or magnetic quivers).\nWe find many
of them having the entire 'Higgs branch' fibered over an unbroken Coulomb
branch direction. By this\, we point out the difference between the Higgs
sector and the Hall-Littlewood sector\, which have been long believed to
be identical for genus 0 theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/82/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenbin Yang (Stanford)
DTSTART:20220531T020000Z
DTEND:20220531T030000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/83
DESCRIPTION:Title: Firewalls from Wormholes\nby Zhenbin Yang (Stanford) as
part of KIAS Strings Seminar\n\n\nAbstract\nI will address an ongoing proj
ect with Douglas Stanford addressing the typical state firewall paradox\,
which is one of the remaining paradox regarding the interior of black hole
s.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thorsten Schimannek (Sorbonne Université)
DTSTART:20220810T070000Z
DTEND:20220810T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/84
DESCRIPTION:Title: Counting BPS states with discrete charges in M-theory\nb
y Thorsten Schimannek (Sorbonne Université) as part of KIAS Strings Semin
ar\n\n\nAbstract\nDiscrete gauge symmetries can arise in M-theory on Calab
i-Yau threefolds with terminal singularities. I will argue that the Gopaku
mar-Vafa invariants are encoded in partition functions associated to diffe
rent values of a discrete flat but topologically non-trivial B-field that
stabilizes the singularities. Locally\, the effect of the B-field can be i
nterpreted as replacing each node by a non-commutative conifold. This pict
ure allows us to derive closed expressions for the constant map contributi
ons to the topological string partition functions on non-commutative crepa
nt resolutions.\nThe main example in this talk will be singular torus fibe
red Calabi-Yau 3-folds that share the same Jacobian fibrations as smooth g
enus one fibered Calabi-Yaus. Somewhat miraculously\, all of the relevant
partition functions can then be recovered at newly discovered non-commutat
ive large volume limits in the stringy Kähler moduli spaces of a rich net
work of interconnected torus fibrations. This makes it possible to extract
the Gopakumar-Vafa invariants associated to discrete charged BPS states i
n M-theory on singular Calabi-Yau threefolds.\nIf time permits\, I will al
so comment on the F-theory interpretation in terms of twisted elliptic gen
era and use this to deduce the 6d discrete 't Hooft anomaly.\nThe talk is
mainly based on 2108.09311 by the speaker and on work in progress with Alb
recht Klemm\, Sheldon Katz and Eric Sharpe.\nThe application to anomalies
is work in progress with Markus Dierigl and Paul Oehlmann.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Institute)
DTSTART:20220704T070000Z
DTEND:20220704T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/85
DESCRIPTION:Title: Supersymmetry and trace formulas\nby Changha Choi (Perim
eter Institute) as part of KIAS Strings Seminar\n\n\nAbstract\nIn the cont
ext of supersymmetric quantum mechanics\, we present a new class of supers
ymmetric localization principles with an application to trace formulas in
mathematics describing thermal partition function. Contrary to the standar
d supersymmetric localization\, this new principle deals with a supertrace
of non-supersymmetric observables. Moreover\, the invariant deformation o
n the path integral side localizes onto non-trivial periodic orbits. We il
lustrate the principle by deriving bosonic trace formulas on compact Lie g
roups.\n
LOCATION:https://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:20260422T225845Z
UID:kias-string-seminars/86
DESCRIPTION:Title: New Anomalies\, TQFTs\, and Confinement in Bosonic Chiral Ga
uge Theories\nby Sungwoo Hong (University of Chicago\, Argonne Nationa
l Lab) as part of KIAS Strings Seminar\n\n\nAbstract\nIn this talk\, I wil
l introduce a class of four dimensional chiral gauge theories which is pur
ely bosonic. By "bosonic" I mean that these theories do not admit any ferm
ionic gauge invariant operators. Then I discuss possibly the most comprehe
nsive set of `t Hooft anomalies that the theory possesses. For this\, I wi
ll discuss general background \nfields that can be consistently activated.
The final outcome of this is a combination of centers of color\, non-abel
ian flavor symmetry\, and U(1) symmetry of the theory\, which we call CFU
backgrounds. Next\, I will discuss anomaly matching assuming confinement a
s the IR phase. I will show that a combination of the following facts impo
ses serious \nchallenges for the anomaly matching (hence confinement as a
possible IR phase):\n(1) Theory is bosonic\, so no possible composite ferm
ions to match continuous anomalies.\n(2) Theorems regarding existence/abse
nce of "symmetry preserving TQFTs"\n(3) Possible vacuum operators and asso
ciated breaking of flavor symmetries.\n(4) Dimensional analysis and RG flo
w.\n\nFocusing on an example of SU(8) theory with one fermion in rank-2 sy
mmetric and three fermions in the rank-2 antisymmetric representations\, I
will argue that vacuum operators consistent with abelian anomalies must h
ave very large scaling dimensions and consideration of continuous flavor s
ymmetry anomaly ever increase this. This suggests that no single vacuum op
erator survives along the RG-trajectory and the theory is more likely to f
low to IR conformal field theory. Considering another example\, SU(8) theo
ry with two fermions in rank-2 symmetric and six fermions in the rank-2 an
tisymmetric representations\, I will again argue that the theory is highly
unlikely to confine and the most feasible possibility is to flow to the I
R CFT. Interestingly\, these rather remarkable results based on non-pertur
bative analysis are consistent with what the perturbative analysis about t
he IR fixed point suggests.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edwan Preau (CNRS)
DTSTART:20220817T070000Z
DTEND:20220817T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/87
DESCRIPTION:Title: Chern-Simons term and baryons in holographic QCD\nby Edw
an Preau (CNRS) as part of KIAS Strings Seminar\n\n\nAbstract\nThe hologra
phic method is one of the only ways of getting analytic insight into most
strongly coupled systems. When numerical methods are not available\, it is
even the best technique we know of to tackle these problems. In particula
r\, lattice QCD is unable to provide results at finite baryon density\, wh
ich is why a lot of effort is put into the study of holographic QCD at hig
h density. Densities beyond the nuclear density are not only a theoretical
frontier\, but are reached in real systems such as neutron star cores and
future heavy ion collision experiments. In this talk\, I will discuss the
most elementary aspect of baryonic physics in holography\, that is the st
udy of a single baryon state. I will start by reviewing the top-down const
ruction of Sakai and Sugimoto\, which makes very clear the crucial role pl
ayed by the topological CS term to construct holographic baryons. I will t
hen introduce the bottom-up framework that we use\, the so-called V-QCD fr
amework\, and explain how the CS term is built in V-QCD. The last part of
my presentation will discuss the construction of a baryon solution in V-QC
D\, with the newly determined CS term.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fengjun Xu (BIMSA\, Beijing)
DTSTART:20220801T070000Z
DTEND:20220801T080000Z
DTSTAMP:20260422T225845Z
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\nA
bstract\nIn this talk\, we will talk about topological defect lines (TDLs)
in two dimensional (conformal) theories and their roles in category symme
tries\, which generalize the notion of symmetries by including non-inverti
ble elements. In particular\, we will introduce their new features in 2d F
ermionic conformal theories\, as well as their strong constraints in the s
tudy of RG flows. Followed by that\, we will utilise these strong constrai
nts to study a RG flow with emergent supersymmetry in two dimensions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabrizio Del Monte (Université de Montreal)
DTSTART:20220712T020000Z
DTEND:20220712T030000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/89
DESCRIPTION:Title: Supersymmetric partition functions and isomonodromic tau fun
ctions\nby Fabrizio Del Monte (Université de Montreal) as part of KIA
S Strings Seminar\n\n\nAbstract\nClass S theories are four-dimensional N=2
QFTs that are obtained by wrapping M5-branes on Riemann surfaces with sin
gular points. In recent years a correspondence between class S theories an
d isomonodromic deformations equations (whose simplest examples are the si
x Painlevé equations) is emerging\, where the so-called isomonodromic tau
function is identified with the dual partition function of the QFT. The t
au functions can be typically written as Fredholm determinants or Pfaffian
s\, providing a fully nonperturbative approach to study partition function
s of class S theories\, relying only on the geometric data entering in the
string theory construction\, and not on a classical action.\n\nAfter revi
ewing the Fredholm determinant formulation of tau functions for spheres wi
th regular singularities\, corresponding to linear quiver gauge theories\,
I will show how the description can be extended to tau functions with ort
hogonal gauge groups\, that are written as Fredholm Pfaffians\, and to tau
functions for tori with regular singularities\, corresponding to circular
quiver gauge theories. I will conclude by showing how the tau function de
scription allows to study the S-duality transformation of the resulting ga
uge theory dual partition function.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Haowu Wang (IBS-CGP\, Pohang)
DTSTART:20220822T070000Z
DTEND:20220822T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/90
DESCRIPTION:Title: Finite groups and automorphic products\nby Haowu Wang (I
BS-CGP\, Pohang) as part of KIAS Strings Seminar\n\n\nAbstract\nIn 1992 Bo
rcherds proved Monstrous Moonshine Conjecture by lifting Mckay--Thomson se
ries to twisted denominator identities of the monster Lie algebra. Borcher
ds' proof inspires an intriguing relation between vertex algebras\, Borche
rds--Kac--Moody algebras and automorphic products. In this talk we introdu
ce several new results related to this relation. We classify nice BKM alge
bras whose denominators are automorphic products. We prove twists of denom
inator identities of the fake monster Lie algebra by the Conway group defi
ne automorphic products on orthogonal groups. To prove the results\, we es
tablish a new expression of automorphic products in terms of Jacobi forms.
Using this representation\, we also show that some infinite products invo
lving twisted elliptic genera of K3 surfaces (appearing in Mathieu Moonshi
ne) are meromorphic Siegel modular forms on congruence subgroups\, which p
roves a conjecture of Miranda Cheng. This talk is based on joint work with
Brandon Williams.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi Zhang (Peking University)
DTSTART:20220824T070000Z
DTEND:20220824T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/91
DESCRIPTION:Title: Gravitational anomalies of higher-spin fields\nby Yi Zha
ng (Peking University) as part of KIAS Strings Seminar\n\n\nAbstract\nIn t
his talk\, I will consider local gravitational anomalies of symmetric tens
or-spinors (fermionic higher spin fields). This is done by using the Atiya
h-Singer index theorem and the spectrum of ghosts. We find new anomaly can
cellations within an infinite tower of these fermionic higher spin fields
with alternating chiralities. Time permitting\, I will also talk about the
antisymmetric case (fermionic p-forms). The ghost spectrum is found using
the Batalin-Vilkovisky field-antifield formalism. We find an intriguing m
atching of anomalies between a chiral fermionic p-form and a (D-p-1)-form.
\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220823T070000Z
DTEND:20220823T080000Z
DTSTAMP:20260422T225845Z
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\nAbstract\n
I 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 time permi
ts\, I will also report recent progress in understanding analogous computa
tions in higher dimensions.\n*organizer's comment\; this is the first lect
ure of three-times-long lecture series.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220825T070000Z
DTEND:20220825T080000Z
DTSTAMP:20260422T225845Z
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\nAbstract\n
I 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 time permi
ts\, I will also report recent progress in understanding analogous computa
tions in higher dimensions.\n*organizer's comment\; this is the second lec
ture of three-times-long lecture series.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Usman Naseer (Uppsala University)
DTSTART:20220905T070000Z
DTEND:20220905T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/95
DESCRIPTION:Title: 7d SYM\, negative coupling and instantons\nby Usman Nase
er (Uppsala University) as part of KIAS Strings Seminar\n\n\nAbstract\nBei
ng non-renormalizable\, SYM theories in d>4 are not well-defined by themse
lves and need non-trivial UV-completions. Using supersymmetric localizatio
n\, one can obtain a glimpse into the structure of these UV completions. F
ocusing on the 7d SYM\, we show that there is a regime where the effective
coupling becomes negative. The theory has instanton branes which contribu
te to the partition function non-trivially. Remarkably\, the full partitio
n functions stays well defined even for negative coupling. Our results imp
ly that the UV completion has two weakly coupled regimes\, one of which is
\, in fact\, gravitational.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220826T070000Z
DTEND:20220826T080000Z
DTSTAMP:20260422T225845Z
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\nAbstract\n
I 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 time permi
ts\, I will also report recent progress in understanding analogous computa
tions in higher dimensions.\n*organizer's comment\; this is the third lect
ure of three-times-long lecture series.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hongfei Shu (BIMSA\, Beijing)
DTSTART:20220919T070000Z
DTEND:20220919T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/97
DESCRIPTION:Title: Wall-crossing of TBA equations and WKB periods for the highe
r order ODE\nby Hongfei Shu (BIMSA\, Beijing) as part of KIAS Strings
Seminar\n\n\nAbstract\nIn this talk\, we study the WKB periods for the thi
rd order ordinary differential equation (ODE) with polynomial potential\,
which is obtained by the Nekrasov-Shatashvili limit of ($A_2\,A_N$) Argyre
s-Douglas theory in the Omega background. In the minimal chamber of the mo
duli space\, we derive the Y-system and the thermodynamic Bethe ansatz (T
BA) equations of quantum integrable model by using the ODE/IM corresponden
ce. The exact WKB periods are identified with the Y-functions. Varying the
moduli parameters of the potential\, the wall-crossing of the TBA equati
ons occurs. We study the process of the wall-crossing from the minimal ch
amber 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 obtained 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 work with
Katsushi Ito and Takayasu Kondo arXiv:2111.11047 [hep-th].\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/97/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Heeyeon Kim (Rutgers)
DTSTART:20220830T070000Z
DTEND:20220830T080000Z
DTSTAMP:20260422T225845Z
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\nAbstract\n
I 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 time permi
ts\, I will also report recent progress in understanding analogous computa
tions in higher dimensions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yuta Hamada (KEK)
DTSTART:20221024T070000Z
DTEND:20221024T080000Z
DTSTAMP:20260422T225845Z
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 propos
e a four-dimensional interpretation of the outgoing state of the scatterin
g of a massless fermion off a Dirac monopole. It has been known that such
a state has fractional fermion numbers and is necessarily outside the Fock
space on top of ordinary perturbative vacuum\, when more than two flavour
s of charged Dirac fermions are considered. In this paper\, we point out t
hat the Fock space of the fermions depends on the rotor degree of freedom
of the monopole and changes by a monopole-fermion s-wave scattering. By up
lifting the fermion-rotor system introduced by Polchinski\, from two to fo
ur dimensions\, we argue that the outgoing state can be understood as a st
ate in a different Fock space.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiung Hwang (IBS\, Daejon)
DTSTART:20221031T070000Z
DTEND:20221031T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/101
DESCRIPTION:Title: Rethinking 3d Mirror Symmetry\nby Chiung Hwang (IBS\, D
aejon) 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 bra
nes in IIB string theory in terms of QFT dualities. This new approach lead
s to a systematic construction of the mirror dual of any 3d N=4 linear qui
ver gauge theory only using a set of basic dualities. Also\, I'll discuss
a relation between 3d mirror symmetry and Seiberg-like dualities.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simone Giacomelli (Milan University)
DTSTART:20221107T070000Z
DTEND:20221107T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/102
DESCRIPTION:Title: A journey through Argyres-Douglas theories\nby Simone G
iacomelli (Milan University) as part of KIAS Strings Seminar\n\n\nAbstract
\nArgyres-Douglas theories are a vast class of N=2 superconformal theories
in four dimensions characterized by the presence of chiral primary operat
ors with fractional scaling dimension. Although these models are strongly-
coupled\, in this talk I will explain how their geometric realization in s
tring theory allows us to extract extremely detailed information about the
ir dynamics and their moduli space of vacua. In particular I will discuss
new results I have obtained about the description of their Higgs branch an
d the determination of their generalized symmetries.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aaron Poole (Kyung Hee University)
DTSTART:20221121T070000Z
DTEND:20221121T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/104
DESCRIPTION:Title: Charges\, conserved quantities\, and fluxes in de Sitter sp
acetime\nby Aaron Poole (Kyung Hee University) as part of KIAS Strings
Seminar\n\n\nAbstract\nIn this talk I will discuss conserved quantities i
n asymptotically locally de Sitter (dS) spacetimes\, motivated by the broa
der aim of a developing a fully nonlinear understanding of the nature of g
ravitational waves in dS. I will begin with a review of the asymptotics of
dS spacetimes\, before showing that one can use the tools of the covarian
t phase space formalism (together with analytic continuation of analogous
results in anti-de Sitter spacetime) in order to derive expressions for sp
atially conserved charges and temporally conserved quantities. I will pres
ent flux formulae which capture the effects of outgoing gravitational radi
ation and illustrate these via application to exact solutions\, with parti
cular emphasis on the Robinson-Trautman dS class. This talk is based on ht
tps://arxiv.org/pdf/2112.14210.pdf (published in PRD) and upcoming work in
collaboration with Kostas Skenderis and Marika Taylor.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sahand Seifnashri (IAS)
DTSTART:20221018T010000Z
DTEND:20221018T020000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/105
DESCRIPTION:Title: Representation theory for non-invertible symmetries and asy
mptotic density of states\nby Sahand Seifnashri (IAS) as part of KIAS
Strings Seminar\n\n\nAbstract\nWe discuss non-invertible symmetries that g
eneralize group-like symmetries in QFTs. We find the appropriate notion of
representation for non-invertible symmetries needed to derive selection r
ules on correlation functions. We use this understanding to derive a Cardy
-like formula for 2d CFTs with a finite non-invertible symmetry. More spec
ifically\, we derive a universal formula for the asymptotic density of sta
tes transforming in an irreducible representation of a non-invertible symm
etry.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yasuyuki Hatsuda (Rikkyo University)
DTSTART:20221205T070000Z
DTEND:20221205T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/106
DESCRIPTION:Title: Fermi-gas approach to supersymmetric localization\nby Y
asuyuki Hatsuda (Rikkyo University) as part of KIAS Strings Seminar\n\n\nA
bstract\nSupersymmetric localization reduces path integrals to finite dime
nsional matrix integrals. For some particular models\, these matrix integr
als can be regarded as the canonical partition function of ideal Fermi-gas
systems. I will first review this Fermi-gas approach in detail. Then\, I
will talk about our recent application to (a special limit of) superconfor
mal indices.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Brandon C. Rayhaun (Stony Brook University)
DTSTART:20221213T070000Z
DTEND:20221213T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/107
DESCRIPTION:Title: Classification of Unitary Rational Conformal Field Theories
with Small Central Charge and Few Primaries\nby Brandon C. Rayhaun (S
tony Brook University) as part of KIAS Strings Seminar\n\n\nAbstract\nTwo-
dimensional conformal field theories are ubiquitous in physics and mathema
tics. In many applications\, it can be useful to have some kind of handle
on the space of physically consistent theories. It is natural to stratify
this space in terms of two parameters: the central charge c\, and the numb
er of primary operators p. In a classic paper\, Schellekens classified all
theories with p=1 primaries and central charge c less than or equal to 24
. In this talk\, I will describe a strategy for pushing the classification
to larger values of p. As a proof of concept\, I will spell out the case
of p=2\, emphasizing the new concepts at play and highlighting several fut
ure directions. Based on joint work with Sunil Mukhi.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/107/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio\, Parra Martinez (Caltech)
DTSTART:20221219T070000Z
DTEND:20221219T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/108
DESCRIPTION:Title: Causality constraints on gravitational effective theories\nby Julio\, Parra Martinez (Caltech) as part of KIAS Strings Seminar\n\
n\nAbstract\nIn this talk I will describe constraints from causality and u
nitarity on 2→2 graviton scattering in weakly-coupled gravitational effe
ctive field theories. Together\, causality and unitarity imply dispersion
relations that connect low-energy observables to high-energy data. Using s
uch dispersion relations\, I will explain how to derive two-sided bounds o
n gravitational Wilson coefficients in terms of the mass M of new higher-s
pin states. Such bounds imply that gravitational interactions must shut of
f uniformly in the limit G→0\, and prove the scaling with M expected fro
m dimensional analysis. In addition they demonstrate the gravity must be w
eakly coupled at all scales below Planck.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/108/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Deliang Zhong (Tel Aviv University)
DTSTART:20230206T070000Z
DTEND:20230206T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/109
DESCRIPTION:Title: Line Operators in Chern-Simons-Matter Theories and Bosoniza
tion in Three Dimensions\nby Deliang Zhong (Tel Aviv University) as pa
rt of KIAS Strings Seminar\n\n\nAbstract\nWe study Chern-Simons theories a
t large N with either bosonic or fermionic matter in the fundamental repre
sentation. The most fundamental operators in these theories are mesonic li
ne operators\, the simplest example being Wilson lines ending on fundament
als. We classify the conformal line operators along an arbitrary smooth pa
th as well as the spectrum of conformal dimensions and transverse spins of
their boundary operators at finite 't Hooft coupling. These line operator
s are shown to satisfy first-order chiral evolution equations\, in which a
smooth variation of the path is given by a factorized product of two line
operators. We argue that this equation\, together with the spectrum of bo
undary operators\, are sufficient to determine these operators' expectatio
n values uniquely. We demonstrate this by bootstrapping the two-point func
tion of the displacement operator on a straight line. We show that the lin
e operators in the theory of bosons and the theory of fermions satisfy the
same evolution equation and have the same spectrum of boundary operators.
\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/109/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenghao Zhong (Oxford)
DTSTART:20230213T070000Z
DTEND:20230213T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/110
DESCRIPTION:Title: Higgsing SCFTs in d=3\,4\,5\,6\nby Zhenghao Zhong (Oxfo
rd) as part of KIAS Strings Seminar\n\n\nAbstract\nWe study supersymmetric
gauge theories with 8 supercharges in d=3\,4\,5\,6. For these theories\,
one can perform Higgsings by turning on VEVs of scalar fields. However\, t
his process can often be difficult when dealing with superconformal field
theories (SCFTs) where the Lagrangian is often not known. Using techniques
of magnetic quivers and a new algorithm we call "Inverted Quiver Subtract
ion"\, 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://researchseminars.org/talk/kias-string-seminars/110/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rishi Mouland (Cambridge)
DTSTART:20230220T080000Z
DTEND:20230220T090000Z
DTSTAMP:20260422T225845Z
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\nI will
motivate and study a holographic duality between on one hand a theory of s
uperconformal quantum mechanics\, and on the other\, M-theory on a particu
lar background. I will exhibit a broad class of black hole solutions\, who
se entropy must be captured by a degeneracy of states in the quantum mecha
nics. Through an asymptotic study of the superconformal index in the super
gravity regime\, I will provide such a microstate counting for those black
holes that are supersymmetric. I will finally discuss on the role of dual
ities of this form in constructing the basic building blocks of holography
for SCFTs in various dimensions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/111/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Nardoni (IPMU)
DTSTART:20230227T070000Z
DTEND:20230227T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/112
DESCRIPTION:Title: Probing Anomalies of Non-Invertible Symmetries with Symmetr
y TFTs\nby Emily Nardoni (IPMU) as part of KIAS Strings Seminar\n\n\nA
bstract\n't Hooft anomalies provide crucial insight into the properties of
quantum field theories\, imposing powerful constraints on their low energ
y dynamics. For invertible global symmetries\, it is known that the 't Hoo
ft anomalies can be characterized by an invertible TQFT in one higher dime
nsion. However\, the analogous statement remains to be understood for non-
invertible symmetries. In this talk we will discuss how the linking invari
ants in a non-invertible TQFT known as the Symmetry TFT can be used as a d
iagnostic for the anomalies of non-invertible symmetries. We will illustra
te this proposal through examples in two and four dimensions\, including 4
d adjoint QCD\, and comment on how knowledge of these anomalies can impose
constraints on the dynamics.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/112/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hossein Yavartanoo (BIMSA)
DTSTART:20230208T070000Z
DTEND:20230208T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/113
DESCRIPTION:Title: Null Surface Thermodynamics\nby Hossein Yavartanoo (BIM
SA) as part of KIAS Strings Seminar\n\n\nAbstract\nFormulating D dimension
al pure Einstein gravity in spacetimes with a null codimension one boundar
y requires addition of boundary degrees of freedom (BDOF) to the usual bul
k gravitons. We construct the solution space perturbatively around the nul
l boundary in which BDOF is described by D functions on the codimension on
e null boundary. Employing covariant phase space formalism we compute char
ges associated with symmetries which rotate us within the solution phase s
pace. We establish that the system admits a thermodynamic description and
that the null surface thermodynamics is a consequence of the diffeomorphis
m 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 gravit
ons through the null boundary we deal with an open thermodynamic system. O
ur analysis here extends the usual laws of black hole thermodynamics in tw
o ways: it is true for any null surface (which is not necessarily the hori
zon of a black hole) which may describe a system out of thermal equilibriu
m and that they are local equations over the null surface.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/113/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lorenz Eberhardt (IAS)
DTSTART:20230307T013000Z
DTEND:20230307T030000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/114
DESCRIPTION:Title: Evaluating one-loop string amplitudes\nby Lorenz Eberha
rdt (IAS) as part of KIAS Strings Seminar\n\n\nAbstract\nI will explain re
cent work with S. Mizera in which we give explicit evaluations of one-loop
open string amplitudes at finite alpha’. Our method involves various de
formations of the contour integral over the modular parameter \\tau. We di
rectly verify that the one-loop string amplitude satisfies unitarity const
raints. I will show explicit plots of the amplitude which will allow us to
verify directly physical conjectures about their behavior\, especially at
high energies.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/114/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Lotito (SNU)
DTSTART:20230313T070000Z
DTEND:20230313T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/115
DESCRIPTION:Title: Extended operators in 4d N=2 SCFTs and vertex algebras\
nby Matteo Lotito (SNU) as part of KIAS Strings Seminar\n\n\nAbstract\nLoc
al Schur operators in 4d N=2 SCFTs form a protected class of operators giv
ing rise to a 2d vertex operator algebra. Following the local operator pic
ture\, we introduce classes of conformal extended operators (lines\, surfa
ces) and study these in twisted Schur cohomology. We show how these operat
ors support a more general algebraic structure compared to the local case\
, giving rise to an extension of the vertex algebra known for local Schur
operators.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/115/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minyoung You (Postech)
DTSTART:20230320T070000Z
DTEND:20230320T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/116
DESCRIPTION:Title: MTC/RCFT correspondence: the fermionic story\nby Minyou
ng You (Postech) as part of KIAS Strings Seminar\n\n\nAbstract\nIt is well
-known that modular tensor categories (MTC)\, which describe 2+1d bosonic
topological orders\, define a 2+1d topological quantum field theory (TQFT)
and capture the modular data of 1+1d rational conformal field theories (R
CFT). After reviewing the bosonic correspondence\, I will explain the gene
ralization of this correspondence to the fermionic case: fermionic topolog
ical orders are described by super-MTCs\, their modular extensions define
a 2+1d spin-TQFT\, and they capture the modular data of 1+1d fermionic RCF
Ts. Then I will discuss the classification of super-MTCs and computation o
f their modular extensions. Finally\, I will discuss the application of th
ese classification results to fermionic RCFTs. In particular\, the knowled
ge of modular extensions allows us to glean information about the R-R sect
or from the data of the NS-NS sector.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/116/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wei Gu (Bonn)
DTSTART:20230327T070000Z
DTEND:20230327T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/117
DESCRIPTION:Title: Heisenberg Spin Chains And Supersymmetric Gauge Theories\nby Wei Gu (Bonn) as part of KIAS Strings Seminar\n\n\nAbstract\nIn this
talk\, we will present how a Heisenberg spin chain emerges from the two-d
imensional N=(2\,2) gauge theory at an intermediate scale\, which relies o
n the renormalization group flow guided by the global symmetries and the d
ynamics of domain walls. Two examples will be discussed: XX-model and its
K-theoretic version. Finally\, we will briefly comment on the unification
of gauge theories from the point of view of the spin chain\, and how to ap
proach other formulations of an integrable system via a new point of view.
\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/117/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Closset (Birmingham)
DTSTART:20230403T070000Z
DTEND:20230403T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/118
DESCRIPTION:Title: The Witten index of 3d N=2 supersymmetric SQCD\, revisited:
Dualities\, moduli spaces and quantum K-theory\nby Cyril Closset (Bir
mingham) as part of KIAS Strings Seminar\n\n\nAbstract\nI will revisit asp
ects of the physics of 3d unitary SQCD\, a 3d N=2 supersymmetric U(N) Cher
n-Simons-matter theory with fundamentals and antifundamental chiral multip
lets. Various subtle aspects come into play when the CS level for the 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 will dis
cuss the low-energy physics at non-zero values of the Fayet-Iliopoulos par
ameter. I will present new detailed checks of infrared dualities in these
theories. Finally\, I will connect this physical story to mathematical res
ults on the quantum K-theory of Grassmannian manifolds. This involves cons
tructing new families of line operators in the 3d gauge theory.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/118/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michèle Levi (Oxford)
DTSTART:20230406T030000Z
DTEND:20230406T040000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/119
DESCRIPTION:Title: Modern QFT for Real-World Gravity (I)\nby Michèle Levi
(Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nPart 1\n-Real-Wor
ld Context\n-Tower of EFTs for PN Gravity\n-Overview of Effective Field Th
eories\nPart 2\n-Bootstrapping One-Particle EFT\n-Tower of EFTs for Binary
Inspiral\n-Bootstrapping EFT of Spinning Particle\nPart 3\n-Feynman Rules
& Graph Topologies\n-Leading PN Corrections & Observables\n-Multiloops &
Public PN Code\nPart 4\n-Higher Spin\n-Higher Loop\n-Beyond Conservative S
ector\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/119/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michèle Levi (Oxford)
DTSTART:20230410T070000Z
DTEND:20230410T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/120
DESCRIPTION:Title: Modern QFT for Real-World Gravity (II)\nby Michèle Lev
i (Oxford) as part of KIAS Strings Seminar\n\n\nAbstract\nPart 1\n-Real-Wo
rld Context\n-Tower of EFTs for PN Gravity\n-Overview of Effective Field T
heories\nPart 2\n-Bootstrapping One-Particle EFT\n-Tower of EFTs for Binar
y Inspiral\n-Bootstrapping EFT of Spinning Particle\nPart 3\n-Feynman Rule
s & Graph Topologies\n-Leading PN Corrections & Observables\n-Multiloops &
Public PN Code\nPart 4\n-Higher Spin\n-Higher Loop\n-Beyond Conservative
Sector\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/120/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin Kaidi (University of Washington)
DTSTART:20230418T020000Z
DTEND:20230418T030000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/121
DESCRIPTION:Title: Non-Supersymmetric Heterotic Branes\nby Justin Kaidi (U
niversity of Washington) as part of KIAS Strings Seminar\n\n\nAbstract\nTh
e common statement that any consistent quantum gravity theory contains dyn
amical objects with all possible charges suggests that there are still a n
umber of hitherto-unidentified branes in string theory. In this talk I wil
l discuss four of these new branes\, focusing on heterotic string theories
. The focus of the discussion will be on the relationship between these br
anes and the lower-dimensional vacua obtained by closed string tachyon con
densation in the ten-dimensional\, non-supersymmetric heterotic string the
ories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/121/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amir-Kian Kashani-Poor (ENS Paris)
DTSTART:20230424T080000Z
DTEND:20230424T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/122
DESCRIPTION:Title: Elliptic genera of non-critical strings and the worldsheet<
/a>\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 compute
the elliptic genera of 6d non-critical strings. The latter are excitations
of 6d superconformal field theories\, best defined via F-theory compactif
ications on Calabi-Yau manifolds. The elliptic genera contain information
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 talk. We
will review what is known about this IR theory\, in particular regarding
its symmetries\, and then formulate an ansatz for the elliptic genus in wh
ich these symmetries are manifest. We have checked this ansatz for many ex
amples\, some of which we shall discuss. This talk is based on joint work
with David Jaramillo Duque.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/122/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sangmin Lee (Seoul National University)
DTSTART:20230501T070000Z
DTEND:20230501T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/123
DESCRIPTION:Title: Classical observables from partial wave amplitudes\nby
Sangmin Lee (Seoul National University) as part of KIAS Strings Seminar\n\
n\nAbstract\nWe study the formalism of Kosower-Maybee-O’Connell (KMOC) t
o extract classical impulse from quantum amplitude in the context of the p
artial wave expansion of a 2-to-2 elastic scattering. We take two compleme
ntary approaches to establish the connection. The first one takes advantag
e of Clebsch-Gordan relations for the base amplitudes of the partial wave
expansion. The second one is a novel adaptation of the traditional saddle
point approximation in the semi-classical limit. In the former\, an interf
erence between the S-matrix and its conjugate leads to a large degree of c
ancellation such that the saddle point approximation to handle a rapidly o
scillating integral is no longer needed. As an example with a non-orbital
angular momentum\, we apply our methods to the charge- monopole scattering
problem in the probe limit and reproduce both of the two angles character
izing the classical scattering. A spinor basis for the partial wave expans
ion\, a non-relativistic avatar of the spinor-helicity variables\, plays a
crucial role throughout our computations.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/123/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Ferrari (Université libre de Bruxelles)
DTSTART:20230417T070000Z
DTEND:20230417T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/124
DESCRIPTION:Title: Random Disks of Constant Curvature\nby Frank Ferrari (U
niversité libre de Bruxelles) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nTwo-dimensional quantum gravity models fall in three classes: Liouvill
e gravity\, for which the geometry is wildly random in the bulk\; topologi
cal gravity\, for which the geometries\, having constant curvature and geo
desic boundaries\, have a finite number of moduli\; and an intermediate cl
ass of models\, which has attracted a lot of attention recently\, for whic
h the metrics have constant curvature but the boundaries can fluctuate wil
dly. These so-called Jackiw-Teitelboim models have been studied in the phy
sics literature\, mainly for negative curvature\, in a certain infinite cu
toff 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 gravity witho
ut assuming that a particular limit is taken\, mainly focusing on the disk
topology. Because the curvature is fixed\, the randomness entirely comes
from the fluctuating disk boundary\, which is a closed curve immersed in t
he hyperbolic space\, the plane or the sphere. The goal is thus to count c
losed curves that bound a disk\, a very interesting and non-trivial combin
atorial problem. Our construction\, which relies on good old conformal gau
ge techniques and insights from recent developments\, yields a new class o
f random geometrical models with many properties that remain to be explore
d. An important upshot of the analysis is that the ansatz and tools that h
ave been used in the infinite cutoff limit cannot be used for any finite v
alue of the cutoff\, even very large.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/124/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jung-Wook Kim (Albert Einstein Institute)
DTSTART:20230508T070000Z
DTEND:20230508T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/125
DESCRIPTION:Title: Frame-dragging effects in scattering amplitudes\nby Jun
g-Wook Kim (Albert Einstein Institute) as part of KIAS Strings Seminar\n\n
\nAbstract\nIn general relativity\, the gravitational field generated by a
spinning body causes immersed test bodies to co-rotate with the central b
ody\, which is also known as the frame-dragging effect. One manifestation
of this effect is known as the gravitational Faraday rotation\, where the
polarisation direction of a linearly polarised electromagnetic/gravitation
al wave rotates due to the background gravitomagnetic field when passing b
y a spinning body. How the effect can be computed using quantum field theo
ry scattering amplitudes\, how the calculation connects with the gravitati
onal two-body problem with spin relevant for gravitational wave physics\,
and what the calculations tell us about universal predictions of quantum g
ravity in the infrared\, will be discussed.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/125/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiming Chang (Tsinghua University)
DTSTART:20230515T070000Z
DTEND:20230515T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/126
DESCRIPTION:Title: Meromorphic Celestial Amplitudes\nby Chiming Chang (Tsi
nghua University) as part of KIAS Strings Seminar\n\n\nAbstract\nCelestial
holography aims to provide a concrete realization of holographic principl
es for quantum gravity in asymptotically flat spacetime. It maps four-dime
nsional scattering amplitudes to celestial amplitudes on the two-dimension
al celestial sphere. However\, celestial amplitudes are known to suffer fr
om two major problems that prevent them from being interpreted as correlat
ion functions of a 2d conformal field theory (CFT). First\, massless three
-point celestial amplitudes are considered to be zero in the literature. S
econd\, the massless four-point celestial amplitudes are distributions rat
her than meromorphic functions. I will discuss massless celestial amplitud
es in a new prescription based on the shadow inner product. The results ar
e free from the previous two problems and take the standard form of CFT co
rrelators.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/126/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masahito Yamazaki (IPMU)
DTSTART:20230522T070000Z
DTEND:20230522T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/127
DESCRIPTION:Title: Revisiting the Gauge/Bethe Correspondence\nby Masahito
Yamazaki (IPMU) as part of KIAS Strings Seminar\n\n\nAbstract\nThe Gauge/B
ethe correspondence claims an equivalence between\n(1) the vacuum equation
of supersymmetric gauge theories with four\nsupercharges and (2) the Beth
e Ansatz equations in quantum integrable\nmodels. While many papers have b
een written about this subject in\nphysics and mathematics\, it is not yet
known how general the\ncorrespondence should hold---at least that has bee
n my opinion for the\npast decades. In this talk\, I will discuss the gene
ral applicability\nof the Gauge/Bethe correspondence using the representat
ions of the\nquiver BPS algebras\, following my research arXiv:2206.13340
[hep-th]\nwith Dimitry Galakhov and Wei Li.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/127/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yunqin Zheng (IPMU)
DTSTART:20230605T070000Z
DTEND:20230605T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/128
DESCRIPTION:Title: Revisiting bosonization and fermionization\nby Yunqin Z
heng (IPMU) as part of KIAS Strings Seminar\n\n\nAbstract\nBosonization an
d fermionization are useful tools in studying 1+1d quantum systems. I will
first revisit this topic from the perspective of topological phases. In p
articular\, I will explain a confusing situation where bosonization “bac
kfires” — bosonizing a fermionic theory still yields a fermionic theor
y — and explain how this puzzle is resolved. I will then apply these und
erstandings to the problem of classification of fermionic chiral CFTs with
central charge c<=16.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/128/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Karapet Mkrtchyan (Imperial College\, London)
DTSTART:20230614T070000Z
DTEND:20230614T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/129
DESCRIPTION:Title: Actions for (twisted) self-duality equations\, their abelia
n interacting generalizations and applications\nby Karapet Mkrtchyan (
Imperial College\, London) as part of KIAS Strings Seminar\n\n\nAbstract\n
I will summarise the ongoing research program\, where we derive Lorentz in
variant Lagrangians for first order equations describing p-form dynamics\,
and apply them for several well-known problems.\nFirst\, we derive the mo
st general non-linear electrodynamics theory in 3+1 dimensions in a democr
atic formulation\, where electric and magnetic potentials enter on equal f
ooting. This includes infinitely many duality-symmetric theories where bot
h S-duality and Lorentz invariance are manifest symmetries of the action.\
nNext\, we derive non-linear self-interactions of self-dual (chiral) p-for
ms in Minkowski spaces of d=4k+2 dimensions\, for which the Lorentz-covari
ant formulation is usually challenging even for the free action. We then g
eneralize these results to a democratic description of arbitrary abelian i
nteracting p-forms in arbitrary dimensions.\nWe also apply our formulation
to derive actions for type II supergravities in 9+1 dimensions employing
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 equatio
ns\, as opposed to pseudo-action formulations.\nTime permitting\, I will c
ompare our formulation to other existing ones as well as mention an ongoin
g work relating these results to another formulation via topological field
theory\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/129/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Muyang Liu (Uppsala University)
DTSTART:20230628T070000Z
DTEND:20230628T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/130
DESCRIPTION:Title: Back to Heterotic Little String Theories on ALE Spaces\
nby Muyang Liu (Uppsala University) as part of KIAS Strings Seminar\n\n\nA
bstract\nI will revisit some features of Heterotic little strings on ALE s
paces motivated by recent developments in our understanding of the structu
res of six-dimensional theories and their continuous 2-group symmetries. I
n particular\, the construction of novel Heterotic E8 × E8 ALE instantoni
c theories through the 6d conformal matter approach is presented\, which e
xtends previous results explored by Aspinwall and Morrison as well as Blum
and Intriligator. This results in the predictions of their T-dual partner
s via the matching of the Coulomb branch and tensor branch data. The ident
ification of dual Little String Theory (LST) is then confirmed through the
geometric engineering in F-theory\, where the T-dual system is realized a
s the inequivalent elliptic fibration structure of the same geometry. In t
he end\, this architecture also inspires us to investigate the geometric e
ngineering limit of heterotic strings on ALE spaces.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/130/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sergei Kuzenko (University of Western Australia)
DTSTART:20230629T070000Z
DTEND:20230629T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/131
DESCRIPTION:Title: Non-compact duality\, super-Weyl invariance and effective a
ctions\nby Sergei Kuzenko (University of Western Australia) as part of
KIAS Strings Seminar\n\n\nAbstract\nThis talk will review recent results
on the quantum dynamics of a system of n Abelian N = 1 vector multiplets c
oupled to (1/2) n(n+1) chiral multiplets which parametrise the Hermitian s
ymmetric space Sp(2n\, R)/ U(n). In the presence of supergravity\, this mo
del is super-Weyl invariant and possesses the maximal non-compact duality
group Sp(2n\, R) at the classical level. These symmetries are shown to be
respected by the logarithmically divergent term (the ``induced action'') o
f the effective action obtained by integrating out the vector multiplets.
In computing the effective action\, one has to deal with non-minimal opera
tors for which the known heat kernel techniques are not directly applicabl
e\, even in flat (super)space. The induced action is derived in closed for
m and has a simple structure. It is a higher-derivative N = 1vsuperconform
al sigma model on Sp(2n\, R)/ U(n). The obtained N = 1 results are then ge
neralised to the case of N = 2 local supersymmetry\, specifically: a syste
m of n Abelian N = 2 vector multiplets coupled to N = 2 chiral scalar mult
iplets parametrising Sp(2n\, R}/ U(n). The induced action is of the type p
roposed\, in particular\, by Gomis\, Hsin\, Komargodski\, Schwimmer\, Seib
erg and Theisen.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/131/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tadashi Okazaki (Southeast University)
DTSTART:20230623T070000Z
DTEND:20230623T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/132
DESCRIPTION:Title: Asymptotic degeneracies of M2-brane SCFTs\nby Tadashi O
kazaki (Southeast University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nWe study the asymptotic growth of the degeneracy of the BPS local opera
tors with large scaling dimensions in the three-dimensional superconformal
field theories describing N M2-branes. From the large N supersymmetric in
dices we obtain the asymptotic formulas for degeneracies of the M2-brane S
CFTs according to the Meinardus theorem. We observe an intriguing universa
l $n^{2/3}$ growth of the degeneracies for various theories of M2-brane SC
FTs. This talk is based on the upcoming work with Hirotaka Hayashi and Tom
oki Nosaka.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/132/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Si Li (Tsinghua University)
DTSTART:20230711T070000Z
DTEND:20230711T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/133
DESCRIPTION:Title: Elliptic Chiral Index and Holomorphic Anomaly\nby Si Li
(Tsinghua University) as part of KIAS Strings Seminar\n\n\nAbstract\nWe i
nvestigate a two-dimensional chiral analogue of the algebraic index theore
m via the theory of chiral algebras developed by Beilinson and Drinfeld. W
e construct a trace map on the elliptic chiral homology of the free beta g
amma-bc system\, and explain the corresponding holomorphic anomaly equatio
n.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/133/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Max Hubner (University of Pennsylvania)
DTSTART:20230712T070000Z
DTEND:20230712T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/134
DESCRIPTION:Title: Generalized Global Symmetries and Gravity\nby Max Hubne
r (University of Pennsylvania) as part of KIAS Strings Seminar\n\n\nAbstra
ct\nGeneralized global symmetries are ubiquitous in QFTs. Given a QFT\, ex
hibiting such symmetries and admitting an embedding into string theory\, w
e may ask what the stringy lift of the corresponding defect and symmetry o
perators are. In many cases both are realized by branes\, wrapped on non-c
ompact cycles\, and are well-understood in large classes of examples. Howe
ver\, once the QFT is coupled to gravity\, general considerations lead to
the expectation that these symmetries are gauged or broken. We consider th
ese and related phenomena in the context of geometric engineering\, and ge
ometrize how completing a local model to a global model leads to dissoluti
on of symmetry structures.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/134/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashish Shukla (Ecole Polytechnique\, CPHT)
DTSTART:20230822T050000Z
DTEND:20230822T060000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/135
DESCRIPTION:Title: Hydrodynamic transport with broken translation invariance\nby Ashish Shukla (Ecole Polytechnique\, CPHT) as part of KIAS Strings
Seminar\n\n\nAbstract\nHydrodynamics provides an effective macroscopic des
cription for systems near thermal equilibrium. Conservation equations for
the currents associated to various symmetries of the system\, along with t
heir constitutive relations expressed as an expansion in gradients\, encap
sulate the dynamics of the system. However\, in real life systems\, some o
f the assumed symmetries might get weakly broken. For instance\, the prese
nce of impurities can lead to a weak explicit breaking of translation inva
riance\, and consequently momentum relaxation. In this talk\, I will discu
ss a systematic approach for constructing a hydrodynamic theory which inco
rporates leading and subleading momentum relaxing effects. The positivity
of entropy production out of equilibrium\, along with Onsager reciprocity
relations\, constrain the hydrodynamic theory. It turns out that the leadi
ng momentum relaxing effects are captured by a single dissipative transpor
t parameter that leads to a Drude-like peak in the thermoelectric response
of the system. Interestingly\, the subleading effects are captured by two
transport parameters which effectively renormalize the weights of the Dru
de peaks in the thermoelectric response. Consequently\, one has to be care
ful while extracting thermodynamic data from thermoelectric transport meas
urements.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20230825T050000Z
DTEND:20230825T070000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/136
DESCRIPTION:Title: Recent progress and challenges in moduli stabilization\
nby Manki Kim (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\nOne of
the most important challenges in string phenomenology is to find semi real
istic vacua that accommodate features of our universe. As the properties o
f isolated vacua are determined dynamically\, via moduli stabilization\, i
t is crucial to understand moduli stabilization. In the first part of this
talk\, I will review moduli stabilization scenarios in string theory. Thi
s will include type II string theories\, Calabi-Yau compactifications\, fl
ux compactifications (GKP)\, and KKLT type scenarios. In the second part o
f the talk\, I will review recent progress and challenges with the outlook
.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/136/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manki Kim (MIT)
DTSTART:20230828T070000Z
DTEND:20230828T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/137
DESCRIPTION:Title: Recent progress and challenges in moduli stabilization\
nby Manki Kim (MIT) as part of KIAS Strings Seminar\n\n\nAbstract\nOne of
the most important challenges in string phenomenology is to find semi real
istic vacua that accommodate features of our universe. As the properties o
f isolated vacua are determined dynamically\, via moduli stabilization\, i
t is crucial to understand moduli stabilization. In the first part of this
talk\, I will review moduli stabilization scenarios in string theory. Thi
s will include type II string theories\, Calabi-Yau compactifications\, fl
ux compactifications (GKP)\, and KKLT type scenarios. In the second part o
f the talk\, I will review recent progress and challenges with the outlook
.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/137/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Inst.)
DTSTART:20230904T070000Z
DTEND:20230904T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/138
DESCRIPTION:Title: Deconfinement in 3d gauge theories\nby Changha Choi (Pe
rimeter Inst.) as part of KIAS Strings Seminar\n\n\nAbstract\nOne of the i
mportant characterization of gauge theory dynamics is whether theory exhib
its confinement or deconfinement. After reviewing well established example
s in 4d and 2d\, we discuss 3d case where several new complications occur.
We then explain how does deconfinement happens in some of the simplest no
n-abelian 3d gauge theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/138/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kohki Kawabata (Tokyo U.)
DTSTART:20231030T070000Z
DTEND:20231030T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/139
DESCRIPTION:Title: Supersymmetric conformal field theories from quantum stabil
izer codes\nby Kohki Kawabata (Tokyo U.) as part of KIAS Strings Semin
ar\n\n\nAbstract\nWe construct fermionic conformal field theories (CFTs) w
hose spectra are characterized by quantum stabilizer codes. We exploit our
construction to search for fermionic CFTs with supersymmetry by focusing
on quantum stabilizer codes of the Calderbank-Shor-Steane type\, and deriv
e simple criteria for the theories to be supersymmetric. We provide severa
l examples of fermionic CFTs that meet the criteria\, and find quantum cod
es that realize N=4 supersymmetry. Our work constitutes a new application
of quantum codes and paves the way for the methodical search for supersymm
etric CFTs.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/139/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takuya Okuda (Tokyo U.\, Komaba)
DTSTART:20231031T050000Z
DTEND:20231031T060000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/140
DESCRIPTION:Title: Narain CFTs and Chern-Simons theories for quantum codes
\nby Takuya Okuda (Tokyo U.\, Komaba) as part of KIAS Strings Seminar\n\n\
nAbstract\nThe theories of classical and quantum codes have rich mathemati
cal structures that capture interesting properties of quantum many-body ph
ysics. 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 fermionization\,
the Z2 gauging procedures can be related to modifications of the momentum
lattice by vectors characterizing the Z2 symmetry. We provide three-dimen
sional interpretations of such Z2 gaugings in terms of Abelian Chern-Simon
s theories\, some of which play the role of symmetry topological field the
ories and are related to others by gauging 1-form symmetries. Codes arise
as data defining topological boundary conditions for the Chern-Simons the
ories. Our bulk construction provides a viewpoint complementary to the re
cent alternative holographic interpretation of Narain code CFTs in the lit
erature.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/140/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yein Lee (Kyung Hee U.)
DTSTART:20230918T070000Z
DTEND:20230918T080000Z
DTSTAMP:20260422T225845Z
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 Strings S
eminar\n\n\nAbstract\nWe construct new supersymmetric solutions correspond
ing to M5-branes wrapped on a topological disc by turning on additional sc
alars in the background. The presence of such scalar fields breaks one of
the U(1) isometries of the internal space\, explicitly realising the break
ing by the Stückelberg mechanism observed previously. In addition\, we co
nstruct a consistent truncation of maximal seven dimensional gauged superg
ravity on the disc to five-dimensional Romans' SU(2) × U(1) gauged superg
ravity\, allowing us to construct a plethora of new supergravity solutions
corresponding to more general states in the dual SCFTs as well as solutio
ns corresponding to M5-branes wrapping four-dimensional orbifolds.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/141/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Norton Lee (IBS)
DTSTART:20230925T070000Z
DTEND:20230925T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/142
DESCRIPTION:Title: Separation of variables and bispectral duality via surface
instanton\nby Norton Lee (IBS) as part of KIAS Strings Seminar\n\n\nAb
stract\nThe N=2 gauge theories in 4 dimension have an intrinsic connection
to algebraic integrable system. The gauge theory of our interest\, the as
ymptotically N=2 superconformal SQCD in 4d\, reveals the structure which h
as bispectral description. On one hand it is a complex generalization of t
he Heisenberg spin chain based on the sl_2 Lie algebra. On the other hand
it is a special case of Gaudin model (a special case of Hitchin system) ba
sed on sl_N Lie algebra. We study the instanton partition function in the
presence of co-dimensional two defects. We prove that the surface instanto
n partition function\, which can be expressed as an integration in the sep
arated variables by Sklyanin\, is the eigenfunction of the bispectral inte
grable systems.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/142/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jaewon Song (KAIST)
DTSTART:20231016T070000Z
DTEND:20231016T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/143
DESCRIPTION:Title: Emergent N=4 Supersymmetry from N=1\nby Jaewon Song (KA
IST) as part of KIAS Strings Seminar\n\n\nAbstract\nWe discover a four-dim
ensional N=1 supersymmetric field theory that is dual to the N=4 super Yan
g-Mills theory with gauge group SU(2n+1) for each n. The dual theory is co
nstructed through the diagonal gauging of the SU(2n+1) flavor symmetry of
three copies of a strongly coupled superconformal field theory (SCFT) of A
rgyres-Douglas type. We find that this theory flows in the infrared to a s
trongly coupled N=1 SCFT that lies on the same conformal manifold as N=4 s
uper Yang-Mills with gauge group SU(2n+1). Our construction provides a hin
t on why certain N=1\, 2 SCFTs have identical central charges (a=c).\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/143/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ruben Minasian (IPhT\, Saclay)
DTSTART:20231024T020000Z
DTEND:20231024T033000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/144
DESCRIPTION:Title: Anomalies and beyond - some modern applications\nby Rub
en Minasian (IPhT\, Saclay) as part of KIAS Strings Seminar\n\n\nAbstract\
nExistence of an anomaly cancellation mechanism in (super)gravity theories
serves as a good guideline for selecting candidates for theories that can
be fully consistent at the quantum level. In this talk I will review vari
ous aspects and somewhat surprising consequences of cancellation of (diffe
rent types of) anomalies in eight and six dimensions. I will also discuss
appearance and importance of more exotic (singular\, non-spin\, non-orient
able) backgrounds.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/144/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kang-Sin Choi (Ewha Women's U.)
DTSTART:20231106T070000Z
DTEND:20231106T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/145
DESCRIPTION:Title: Renormalization and the Hierarchy Problem\nby Kang-Sin
Choi (Ewha Women's U.) as part of KIAS Strings Seminar\n\n\nAbstract\nWe r
econsider the renormalization of observables\, not bare parameters\, in qu
antum field theory. We have a better understanding of the finiteness and t
he scheme independence of physical parameters\, especially of the scalar m
ass. After reviewing the vacuum polarization whose quadratic divergence is
illusory\, we calculate the top-quark correction to the Higgs mass\, whic
h is finite\, exhibits power running and is independent of the Wilsonian c
utoff.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Dorey (Cambridge U.\, DAMTP)
DTSTART:20231127T070000Z
DTEND:20231127T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/146
DESCRIPTION:Title: Building a Black Hole in Quantum Mechanics\nby Nick Dor
ey (Cambridge U.\, DAMTP) as part of KIAS Strings Seminar\n\n\nAbstract\nI
will describe recent progress in formulating and testing a dual holograph
ic description of ultra-spinning black holes in terms of finite dimensiona
l quantum mechanics.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ram Brustein (Ben-Gurion University)
DTSTART:20231120T070000Z
DTEND:20231120T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/147
DESCRIPTION:Title: What’s inside a black hole?\nby Ram Brustein (Ben-Gur
ion University) as part of KIAS Strings Seminar\n\n\nAbstract\nI will pres
ent general arguments\, based on fundamental physics principles\, as to wh
y we should expect a significant\, horizon scale\, departure from semiclas
sical gravity inside astrophysical black holes. Then\, I will present a si
mple model which realizes this idea: the frozen star model. I will show th
at a static frozen star looks exactly like a Schwarzschild black hole to a
n external observer and that it is sourced by a “string fluid”. Then
I will present the rotating frozen star and show that it looks exactly li
ke a Kerr black hole to an external observer. I will end by discussing the
stability and the spectrum of internal modes of the frozen stars and show
that they possess an interesting spectrum of non-relativistic modes.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/147/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Linardopoulos (APCTP)
DTSTART:20231207T070000Z
DTEND:20231207T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/148
DESCRIPTION:Title: Holographic correlators of semiclassical states in defect C
FTs\nby Georgios Linardopoulos (APCTP) as part of KIAS Strings Seminar
\n\n\nAbstract\nWe set up the computation of correlation functions for ope
rators that are dual to semiclassical string states in strongly coupled de
fect conformal field theories (dCFTs). In the dCFT that is dual to the D3-
D5 probe-brane system\, we calculate the correlation function of two heavy
operators perturbatively\, in powers of the conformal ratio. We find that
the leading term agrees with the prediction of the operator product expan
sion (OPE). In the case of two heavy BMN operators\, we find agreement in
subleading orders as well.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomasevic (University of Amsterdam)
DTSTART:20231218T080000Z
DTEND:20231218T090000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/149
DESCRIPTION:Title: The correspondence between rotating black holes and fundame
ntal strings\nby Marija Tomasevic (University of Amsterdam) as part of
KIAS Strings Seminar\n\n\nAbstract\nThe correspondence principle between
strings and black holes is a general framework for matching black holes an
d massive states of fundamental strings at a point where their physical pr
operties (such as mass\, entropy and temperature) smoothly agree with each
other. This correspondence becomes puzzling when attempting to include ro
tation: At large enough spins\, there exist degenerate string states that
seemingly cannot be matched to any black hole. Conversely\, there exist bl
ack holes with arbitrarily large spins that cannot correspond to any singl
e-string state. We discuss in detail the properties of both types of objec
ts and find that a correspondence that resolves the puzzles is possible by
adding dynamical features and non-stationary configurations to the pictur
e. Our scheme incorporates all black hole and string phases as part of the
correspondence\, save for one outlier which remains enigmatic: the near-e
xtremal Kerr black hole. Along the way\, we elaborate on general aspects o
f the correspondence that have not been emphasized before.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Saebyeok Jeong (CERN)
DTSTART:20240117T070000Z
DTEND:20240117T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/150
DESCRIPTION:Title: Q-operators as surface defects\; bispectral duality and sep
aration of variables by surface defect transition\nby Saebyeok Jeong (
CERN) as part of KIAS Strings Seminar\n\n\nAbstract\nI will first explain
how the quantum integrable system arising from the 4d N=2 gauge theory can
be viewed as a XXX spin chain defined on bi-infinite Yangian modules. I w
ill present the "regular monodromy" surface defect that provides a disting
uished basis of this module by their vevs at discrete loci in the space of
Coulomb vacua. Then I will introduce the "canonical" surface defect on to
p of it which serves as the Q-operator. The action of the Q-operator will
be shown to be diagonal due to the cluster decomposition of the surface de
fects. As a consequence\, the mentioned basis elements simultaneously diag
onalize the transfer matrices of the Yangian. I will connect this XXX spin
chain with a Hitchin integrable system (a Gaudin model in our case) by em
bedding the 4d N=2 theory into string/M-theory and applying a string duali
ty. I will show the Coulomb/Higgs transition that the canonical surface de
fect undergoes manifests as the transition between the Q-operator for the
XXX spin chain and the Hecke operator for the Gaudin model. It leads to an
exact one-to-one matching between their quantum Hamiltonians as well as t
heir quantum spectra. Finally\, I will explain how the regular monodromy s
urface defect experiences a transition to multiple canonical surface defec
ts. The transition leads to the quantum separation of variables for both t
he XXX spin chain and the Gaudin model.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/150/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Albrecht Klemm (BCTP\, U. Bonn)
DTSTART:20240215T013000Z
DTEND:20240215T023000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/151
DESCRIPTION:Title: Calabi-Yau period motives in quantum field theory and gener
al relativity\nby Albrecht Klemm (BCTP\, U. Bonn) as part of KIAS Stri
ngs Seminar\n\n\nAbstract\nWe show that Feynman integrals occurring in sta
ndard quantum field theories or perturbative worldline approaches to the s
cattering of real black holes are related to periods of Calabi-Yau varieti
es of various dimensions. After defining what mathematical properties a Ca
labi-Yau period motive has\, we explain how the applications of the latter
lead to an efficient analytic evaluation of the Feynman integrals in dime
nsional regularisation.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/151/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohammad Akhond (Kyoto University)
DTSTART:20240226T070000Z
DTEND:20240226T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/152
DESCRIPTION:Title: 5d SCFTs and their non-supersymmetric cousins\nby Moham
mad Akhond (Kyoto University) as part of KIAS Strings Seminar\n\n\nAbstrac
t\nI will argue that combining old ideas such as dualities and exact resul
ts in SUSY QFTs supplemented with recent techniques such as SPT phases and
generalised anomalies can shed light on strong coupling dynamics of non-S
USY theories. I will in particular show that non-SUSY gauge theories\, whi
ch 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://researchseminars.org/talk/kias-string-seminars/152/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changha Choi (Perimeter Institute)
DTSTART:20240228T020000Z
DTEND:20240228T030000Z
DTSTAMP:20260422T225845Z
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\nAbstract\
n1/2 BPS surface defect (Gukov-Witten operator) in N=4 SYM is an extraordi
narily rich physical probe where various non-trivial defect correlation fu
nctions have been computed in the strong coupling limit using the AdS/CFT
correspondence. From these results\, there has been a long standing conjec
ture about some exact matrix model description of the defect correlation f
unctions. In this talk\, we corroborate and also improve the conjecture us
ing supersymmetric localization.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/153/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Changhyun Ahn (Kyungpook Natl. U.)
DTSTART:20240318T070000Z
DTEND:20240318T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/154
DESCRIPTION:Title: On Celestial Holography\nby Changhyun Ahn (Kyungpook Na
tl. U.) as part of KIAS Strings Seminar\n\n\nAbstract\nA quantum gravity i
s an outstanding open problem in the current modern physics. The complete
theory of quantum gravity would provide the microscopic structure underlyi
ng systems whose long distance behavior is described by the general relati
vity of Einstein’s theory. Celestial holography studied during last ten
years provides a new approach to quantum gravity in four dimensional asymp
totically flat spacetimes by searching for its holographic correspondence.
Celestial holography proposes a duality between gravitational scattering
in four dimensional asymptotically flat spacetimes and a conformal field t
heory living on the two dimensional celestial sphere. I will present 1) In
troduction\, 2) Infrared structure of gravity\, 3) From four dimensional g
ravity to two dimensional celestial conformal field theory\, 4) Celestial
amplitudes and celestial OPEs\, 5) Soft symmetries\, 6) My recent works\,
and 7) Open problems. This will provide the way to observe directly (or in
directly) the evidence of superstring (or M) theory in our real world.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/154/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Vikman (FZU\, CAS)
DTSTART:20240325T070000Z
DTEND:20240325T080000Z
DTSTAMP:20260422T225845Z
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 recent w
orks Phys.Rev.Lett. 128 (2022) 4\, 041301 and e-Print: 2305.09631. There w
e presented a large class of mechanical models where a canonical degree 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 analytically
that the classical motion of the system is finite i.e. Lagrange stable for
all initial conditions\, notwithstanding that the conserved Hamiltonian i
s unbounded from below and above. Moreover\, there are Lyapunov stable equ
ilibrium configurations. Numerical computations fully supported this. An i
mportant update is that such stable ghosts can also appear in systems with
a simple polynomial interaction. Systems with negative kinetic terms ofte
n appear in modern cosmology\, quantum gravity\, and high energy physics\,
and are usually deemed as unstable. Our result demonstrates that\, for me
chanical systems\, this common lore can be too naïve and that a stable li
ving with ghosts is possible.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/155/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Seok Kim (POSTECH)
DTSTART:20240408T070000Z
DTEND:20240408T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/156
DESCRIPTION:Title: On the monotonicity of the renormalization group flow in bo
th nonequilibrium thermodynamics and geometrical perspectives\nby Ki-S
eok Kim (POSTECH) as part of KIAS Strings Seminar\n\n\nAbstract\nFollowing
the entropy production in nonequilibrium thermodynamics\, we show the mon
otonicity of the renormalization group (RG) flow. Then\, we clarify the co
nnection between the monotonicity of the RG flow and the Weyl anomaly\, di
scussing the a- or c-theorem. To investigate the monotonicity of the RG fl
ow in the perspectives of both nonequilibrium thermodynamics and geometry\
, we construct a holographic dual effective field theory of the cohomologi
cal type a la Witten\, which manifests the RG flow in the level of an effe
ctive action. This effective field theory framework allows us to introduce
various kinds of entropy functionals\, where their monotonic behaviors pl
ay central roles in the monotonicity of the RG flow. We discuss how the Gi
bbs-type entropy functional\, the holographic entropy functional\, the Per
elman’s entropy functional\, and the Weyl anomaly are all deeply related
\, based on our holographic dual effective field theory.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/156/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ryo Suzuki (Southeast U.)
DTSTART:20240411T070000Z
DTEND:20240411T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/157
DESCRIPTION:Title: Tensionless Limit of Pure-Ramond-Ramond AdS3/CFT2\nby R
yo Suzuki (Southeast U.) as part of KIAS Strings Seminar\n\n\nAbstract\nTh
e best-studied example of AdS/CFT is the correspondence between the supers
tring in AdS5 x S5 and N=4 SYM in four dimensions. Much less is known abou
t AdS3/CFT2\, such as the details of SCFT dual to the superstring in 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\, Frolo
v and Sfondrini proposed Mirror TBA equations that predicts the exact ener
gy of string states. We generalized the mirror TBA for excited states and
studied the solutions in the tensionless limit. We found that\, despite no
n-trivial wrapping corrections caused by massless virtual particles in the
mirror\, the energy of a tensionless string is similar to the spectrum of
free particles.\n\nThis work is based on joint arXiv:2303.02120\, 2308.11
576 with Alberto Brollo\, Dennis le Plat and Alessandro Sfondrini.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/157/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin (USC)
DTSTART:20240315T020000Z
DTEND:20240315T030000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/158
DESCRIPTION:Title: High dimension operators of high dimension CFTs\nby Nat
han Benjamin (USC) as part of KIAS Strings Seminar\n\n\nAbstract\nI will d
iscuss universal behavior of conformal field theory (CFT) data at high en
ergies. In particular I will discuss universal formulas for both the entro
py and the three-point-functions of local operators for d-dimensional 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-dimensi
onal version of Cardy's formula for 2d CFTs. I will also discuss holograph
ic interpretations of this result. Based on arXiv:2306.08031 and work to a
ppear.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/158/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Viatcheslav Mukhanov
DTSTART:20240319T070000Z
DTEND:20240319T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/159
DESCRIPTION:Title: Resolving Singularities in Gravity\nby Viatcheslav Mukh
anov as part of KIAS Strings Seminar\n\n\nAbstract\nI will show how the si
ngularities in Friedmann Universe\, Kasner Universe and in Black hole can
be easily resolved by modifying the Einstein equations at high curvatures
with implementation of the concept of limiting curvature.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/159/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi Zhang (Peking U.)
DTSTART:20240429T070000Z
DTEND:20240429T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/160
DESCRIPTION:Title: Understanding Fermionic Generalized Symmetries\nby Yi Z
hang (Peking U.) as part of KIAS Strings Seminar\n\n\nAbstract\nWe explore
new aspects of internal fermionic shifting symmetries present in physical
systems such as free Dirac spinors and p-form tensor-spinor fields. We pr
opose a novel procedure to gauge these global symmetries which also introd
uces a new Stückelberg mechanism to give a mass to free fermionic fields.
Furthermore we find new magnetic fermionic symmetries in these physical s
ystems whose charged objects are disorder operators. For the case of a Dir
ac spinor we discuss a dual description where the magnetic symmetry acts o
n the holonomies of a dual 2-form tensor-spinor. Further generalizations s
uch as higher-group-like structures are also discussed.\n
LOCATION:https://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:20260422T225845Z
UID:kias-string-seminars/161
DESCRIPTION:Title: Quantum Improved Kerr Black Holes and Thermodynamics\nb
y Nobuyoshi Ohta (Natl. Central U.\, Taiwan & Kindai U.\, Osaka) as part o
f KIAS Strings Seminar\n\n\nAbstract\nThe asymptotic safety approach to th
e quantum gravity suggests that the Newton coupling depends on the energy
scale. To make connection to the black hole geometry\, we have to identify
the energy scale to certain length scale\, but there has not been any pri
nciple to constrain the identification. We show that the first law of the
thermodynamics gives quite nontrivial constraint on the identification\, a
nd this leads to interesting consequences on the expression of the entropy
and black hole geometry. The quantum improved entropy reduces to the Beke
nstein-Hawking formula in the semi-classical limit\, and suitable choice o
f the identification leads to the possibility of singularity resolution.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/161/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matteo Lotito (SNU)
DTSTART:20240513T070000Z
DTEND:20240513T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/162
DESCRIPTION:Title: The Weak Gravity conjecture in Perturbative String Theory\nby Matteo Lotito (SNU) as part of KIAS Strings Seminar\n\n\nAbstract\n
I will discuss the weak gravity conjecture (WGC) starting from the origina
l statement and motivation\, showing the evidence for various forms of the
conjecture in string scenarios. Connecting the WGC to other\, related\, c
onjectures\, I will describe the results of a recent paper (2401.14449)\,
where\, by refining details of the derivation\, we are finally able to pro
vide a comprehensive proof of the WGC using a string worldsheet constructi
on\, albeit\, for now\, restricted to the perturbative bosonic string.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/162/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hee-Joong Chung (JNU)
DTSTART:20240520T070000Z
DTEND:20240520T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/163
DESCRIPTION:by Hee-Joong Chung (JNU) as part of KIAS Strings Seminar\n\nAb
stract: TBA\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/163/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fedor Popov (NYU)
DTSTART:20240603T070000Z
DTEND:20240603T080000Z
DTSTAMP:20260422T225845Z
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 study of
DSSYK and the non-commutative nature of its bulk dual\, we review and anal
yze an example of a non-commutative spacetime known as the quantum disk pr
oposed by L. Vaksman. The quantum disk is defined as the space whose isome
tries are generated by the quantum algebra Uq(su1\,1). We review how this
algebra is defined and its associated group SUq(1\,1) that it generates\,
highlighting its non-trivial coproduct that sources bulk non-commutativity
. We analyze the structure of holography on the quantum disk and study the
imprint of non-commutativity on the putative boundary dual.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/164/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongwook Ghim (RIKEN)
DTSTART:20240610T070000Z
DTEND:20240610T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/165
DESCRIPTION:Title: Digital quantum simulation for the spectroscopy of Schwinge
r model\nby Dongwook Ghim (RIKEN) as part of KIAS Strings Seminar\n\n\
nAbstract\nWe present a method for computing energy spectra in lattice fie
ld theory using digital quantum simulation. The method\, inspired by coher
ent imaging spectroscopy\, perturbs the vacuum with a time-oscillating que
nch and analyzes the resulting loss in vacuum-to-vacuum probability to ide
ntify excited levels. We apply this technique to (1+1)-dimensional quantum
electrodynamics with topological angle\, known as the Schwinger model. Us
ing a classical simulator\, we prepare the vacuum on a lattice with the ad
iabatic method and apply various quenches through Suzuki-Trotter approxima
tion. The computational complexity estimation suggests the method be poten
tially efficient with early fault-tolerant quantum computers.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/165/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ki-Hong Lee (KAIST)
DTSTART:20240617T070000Z
DTEND:20240617T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/166
DESCRIPTION:Title: Classification of simple large N SCFTs in 4d\nby Ki-Hon
g Lee (KAIST) as part of KIAS Strings Seminar\n\n\nAbstract\nI will discus
s 4d N=1 SCFTs obtained at the IR fixed points of UV gauge theories with s
imple gauge groups that admit the large N limit. These SCFTs are classifie
d into 38 theory classes solely based on group theory. I will introduce so
me exotic cases that exhibit dense spectra of low-lying operators and comp
are their properties with those of holographic SCFTs. Finally\, I will exp
lore a universal aspect of these large N SCFTs inspired by the CFT Weak Gr
avity Conjecture.\n\nReferences: arXiv: 2007.16165\, 2308.01717\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/166/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu (Southeast U.)
DTSTART:20240708T070000Z
DTEND:20240708T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/167
DESCRIPTION:Title: Trans-series for Hofstadter Butterfly\nby Jie Gu (South
east U.) as part of KIAS Strings Seminar\n\n\nAbstract\nThe Harper-Hofstad
ter model is an interesting 2d electron model in a square lattice with a u
niform and perpendicular magnetic field\, and its energy spectrum as a fun
ction of the magnetic field displays an intriguing pattern\, known as the
Hofstadter's butterfly\, which implies very rich non-perturbative structur
es. Using a surprising connection with supersymmetric field theory and top
ological string\, we write down a conjectural formula of the full energy t
rans-series which includes all orders instanton corrections when the magne
tic flux is 2\\pi/Q for natural numbers Q\, and we verify our formula with
high precision numerical calculations.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/167/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Norton Lee (IBS)
DTSTART:20240722T070000Z
DTEND:20240722T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/168
DESCRIPTION:Title: Dimer integrable model: Hamiltonians on a chess board\n
by Norton Lee (IBS) as part of KIAS Strings Seminar\n\n\nAbstract\nDimer m
odel\, also known as brane tiling or domino tiling\, is a study of tessell
ation of an Euclidean plane. We consider a class of integrable systems pro
posed by Goncharov and Kenyon in correspondence with the dimer models on a
torus. These integrable systems are the generalization of the affine A-ty
pe relativistic Toda lattice. According to the correspondence\, every dime
r model defines an integrable system\, whose conserving charges can be sys
tematically calculated based on the perfect matching of the bipartite grap
h. We will explain two ways of modifying the known dimer graph\, which gen
erates new integrable systems. The quantization of these integrable system
s can be solved by Bethe/Gauge correspondence with co-dimensional two defe
ct introduced in 5d N=1 supersymmetric gauge theories.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/168/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martí Rosselló (Academica Sinica Taiwan)
DTSTART:20240624T070000Z
DTEND:20240624T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/169
DESCRIPTION:Title: The Giant Graviton Expansion in AdS5 x S5\nby Martí Ro
sselló (Academica Sinica Taiwan) as part of KIAS Strings Seminar\n\n\nAbs
tract\nThe 1/2-BPS index of N=4 SYM with gauge group U(N) can be written a
s the large N answer times an infinite series of finite N corrections. Thi
s expansion is called the giant graviton expansion. I will explain how suc
h an expansion arises in the bulk as a result of the localization of the p
ath integral which computes the bulk 1/2-BPS index to a product of small f
luctuations of the vacuum and of the collective modes of an arbitrary numb
er of maximal giant gravitons.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/169/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Peter Koroteev (UC Berkeley)
DTSTART:20240717T070000Z
DTEND:20240717T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/170
DESCRIPTION:Title: Opers\, Gauge Theories\, and Integrability\nby Peter Ko
roteev (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-connected com
plex simple Lie group\, and prove some general results about their structu
re. Then I establish a one-to-one correspondence between the set of such o
pers and the set of nondegenerate solutions of a system of Bethe Ansatz eq
uations as well as the so-called QQ-systems. I’ll discuss the oper inter
pretation of Seiberg-like dualities in supersymmetric quiver theories in t
hree dimensions.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/170/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minkyoo Kim (CQUeST)
DTSTART:20240821T070000Z
DTEND:20240821T080000Z
DTSTAMP:20260422T225845Z
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 operators
of N=4 SYM. Because they have dimensions over the order of N\, their corre
lation functions\, etc.\, are not sufficient as planar contributions even
in the large N limit\, and nonplanar effects are important. In particular\
, we would like to propose a holographic dual of a black hole from heavy o
perators with a dimension of order N^2. These are constructed from restric
ted Schur polynomials and the corresponding Young diagrams are given by th
e VKLS curve and a curve which generalizes the VKLS shape when finite N co
nstraints are important. We also give some comments on the dilatation prob
lem for these operators and its application.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/171/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Tong (Cambridge University)
DTSTART:20240909T070000Z
DTEND:20240909T083000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/172
DESCRIPTION:Title: Fermion-Monopole Scattering is Weird.\nby David Tong (C
ambridge University) as part of KIAS Strings Seminar\n\n\nAbstract\nWhen c
hiral fermions scatter off monopoles\, strange things happen. In many situ
ations\, including in the Standard Model\, there is an apparent paradox be
cause it seems impossible for scattering to be consistent with gauge symme
try. I’ll explain how this paradox arises and describe its resolution\,
in which outgoing radiation sits in a twisted sector of the Hilbert space.
\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/172/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cynthia Yan
DTSTART:20241007T020000Z
DTEND:20241007T030000Z
DTSTAMP:20260422T225845Z
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 feat
ure the N =2 supersymmetric Sachdev-Ye-Kitaev (SYK) model shares with extr
emal black holes is an exponentially large number of ground states that pr
eserve supersymmetry. In fact\, the dimension of the ground state subsecto
r is a finite fraction of the total dimension of the SYK Hilbert space. Th
is fraction has a remarkably simple bulk interpretation as the probability
that the zero-temperature wormhole --- a supersymmetric Einstein-Rosen br
idge --- has vanishing length. Using chord techniques\, we compute the zer
o-temperature Hartle-Hawking wavefunction\; the results reproduce the grou
nd state count obtained from boundary index computations\, including non-p
erturbative corrections. Along the way\, we improve the construction of th
e super-chord Hilbert space and show that the transfer matrix of the empty
wormhole enjoys an enhanced N = 4 supersymmetry. We also obtain express
ions for various two point functions at zero temperature. Finally\, we fin
d the expressions for the supercharges acting on more general wormholes wi
th matter and present the superchord algebra.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/173/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Roberts
DTSTART:20241021T070000Z
DTEND:20241021T080000Z
DTSTAMP:20260422T225845Z
UID:kias-string-seminars/174
DESCRIPTION:Title: Supersymmetric magnetic defects\nby Matthew Roberts as
part of KIAS Strings Seminar\n\n\nAbstract\nDefect CFTs provide an excitin
g new playground to study RG flows and their endpoints. After reviewing so
me basics of defect CFTs\, I will present a detailed study of supersymmetr
ic magnetic solenoid defects (also known as monodromy defects). We will me
asure the response of the system to the insertion of the magnetic solenoid
\, and in the four dimensional case will calculate new central charges whi
ch appear in the trace anomaly. We close by commenting on new possible mon
otonic quantities in these new mixed dimensional systems.\n
LOCATION:https://researchseminars.org/talk/kias-string-seminars/174/
END:VEVENT
END:VCALENDAR