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BEGIN:VEVENT
SUMMARY:Sourav Roychowdhury (Chennai Mathematical Institute)
DTSTART:20211123T060000Z
DTEND:20211123T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/1
DESCRIPTION:Title: Non-Abelian T-dual of Klebanov-Tseytlin background and its Penr
ose limits\nby Sourav Roychowdhury (Chennai Mathematical Institute) as
part of APCTP String Seminars\n\n\nAbstract\nIn this talk I will discuss
Klebanov-Tseytlin background and it’s non-Abelian T-dual ge- ometry. In
particular I will show that the T-dual background admits pp-wave geometry
in the neighbourhood of appropriate null geodesic. I will make comments on
possible dual gauge theory for our pp-wave background.\n\nZOOM Link: http
s://us06web.zoom.us/meeting/register/tZItc-ispz4jHtdDWcjdm34TnKq3rg-a5U8s\
n\n※ You can join the webinar with a link generated after the registrati
on.\n※ In the case that a passcode is required to join\, type 0000.\n※
When entering the meeting\, please rename your profile as your full name
(affiliation) *E.g. Gildong Hong (APCTP)\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211125T050000Z
DTEND:20211125T060000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/2
DESCRIPTION:Title: Higher spin algebra and minimal orbits/representations\nby
Euihun Joung (Kyunghee University) as part of APCTP String Seminars\n\n\nA
bstract\nCoadjoint orbits of Lie group and its quantizations have various
interesting applications in physics. In the first lecture\, I will introdu
ce them within the context of higher spin gravity. In the second and third
lectures\, its relation to dual pair correspondence and the relevant repr
esentation theory analysis will be discussed.\n\nZOOM Link: https://us06we
b.zoom.us/meeting/register/tZItd-muqDsuGNEqRDTd6p5K-3dHgeBm-acl\n\n※ You
can join the webinar with a link generated after the registration.\n※ I
n the case that a passcode is required to join\, type 0000.\n※ When ente
ring the meeting\, please rename your profile as your full name (affiliati
on) *E.g. Gildong Hong (APCTP)\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211126T010000Z
DTEND:20211126T020000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/3
DESCRIPTION:Title: Coadjoint orbits and Dual pair correspondence I\nby Euihun
Joung (Kyunghee University) as part of APCTP String Seminars\n\n\nAbstract
\nCoadjoint orbits of Lie group and its quantizations have various interes
ting applications in physics. In the first lecture\, I will introduce them
within the context of higher spin gravity. In the second and third lectur
es\, its relation to dual pair correspondence and the relevant representat
ion theory analysis will be discussed.\n\nZOOM Link: https://us06web.zoom.
us/meeting/register/tZItd-muqDsuGNEqRDTd6p5K-3dHgeBm-acl\n\n※ You can jo
in the webinar with a link generated after the registration.\n※ In the c
ase that a passcode is required to join\, type 0000.\n※ When entering th
e meeting\, please rename your profile as your full name (affiliation)
*E.g. Gildong Hong (APCTP)\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211126T020000Z
DTEND:20211126T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/4
DESCRIPTION:Title: Coadjoint orbits and Dual pair correspondence II\nby Euihun
Joung (Kyunghee University) as part of APCTP String Seminars\n\n\nAbstrac
t\nCoadjoint orbits of Lie group and its quantizations have various intere
sting applications in physics. In the first lecture\, I will introduce the
m within the context of higher spin gravity. In the second and third lectu
res\, its relation to dual pair correspondence and the relevant representa
tion theory analysis will be discussed.\n\nZOOM Link: https://us06web.zoom
.us/meeting/register/tZItd-muqDsuGNEqRDTd6p5K-3dHgeBm-acl\n\n※ You can j
oin the webinar with a link generated after the registration.\n※ In the
case that a passcode is required to join\, type 0000.\n※ When entering t
he meeting\, please rename your profile as your full name (affiliation)
*E.g. Gildong Hong (APCTP)\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hyojoong Kim (Kyunghee University)
DTSTART:20211207T060000Z
DTEND:20211207T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/5
DESCRIPTION:Title: On the Superconformal Index of Chern-Simons theories and their
KK Spectrometry\nby Hyojoong Kim (Kyunghee University) as part of APCT
P String Seminars\n\n\nAbstract\nWe study the large-$N$ limit of superconf
ormal index for two strongly interacting Chern-Simons theories in three di
mensions with $\\mathcal{N} = 2$ supersymmetry\, and compare the result ag
ainst the AdS/CFT dual\, namely the data of full Kaluza-Klein reduction sp
ectra obtained using the exceptional field theory technique. The two theor
ies of interest are mABJM and GJV theories\, which are obtained as IR fixe
d point of RG whose UV description is ABJM and maximally supersymmetric Ya
ng-Mills theory respectively. We confirm agreement and the duality persist
s. For the case of mABJM it turns out that we need a refinement of the gra
vity index which reflects the fact that the UV description on the field th
eory side has enhanced global symmetry.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Binata Panda (ISM)
DTSTART:20211124T060000Z
DTEND:20211124T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/6
DESCRIPTION:Title: Seeley DeWitt Coefficients and Logarithmic entropy corrections
for black holes in generalized Einstein-Maxwell theory\nby Binata Pand
a (ISM) as part of APCTP String Seminars\n\n\nAbstract\nLogarithmic correc
tions to the entropy of different classes of black holes are interesting t
o study in the context of testing a quantum theory of gravity. These are
special quantum corrections that are universal\, most dominant\, and entir
ely computable from low energy data (i.e.\, massless fluctuations and thei
r coupling to the black hole background). Euclidean gravity approach has b
een successful in computing these corrections to extremal and non-extremal
black hole entropy. One of the important ingredients for this approach is
to calculate the Seeley-DeWitt coefficients of the kinetic operator of th
e massless fields in the black hole background. In this talk\, we will di
scuss the computation of Seeley-DeWitt coefficients as well as the logarit
hmic corrections to the entropy of black holes in a generalized Einstein-M
axwell theory (minimally coupled to arbitrary numbers of additional massle
ss scalar\, vector\, spin-1/2\, and spin-3/2 fields).\n\nZOOM Link: https
://us06web.zoom.us/meeting/register/tZMlc-CvrT4tHNGL7v7TQqFV-5Tg14foC0gx\n
\n※ You can join the webinar with a link generated after the registratio
n.\n※ In the case that a passcode is required to join\, type 0000.\n※
When entering the meeting\, please rename your profile as your full name (
affiliation) *E.g. Gildong Hong (APCTP)\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Akhil Sivakumar (ICTS)
DTSTART:20211222T060000Z
DTEND:20211222T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/7
DESCRIPTION:Title: Fluctuating Hydrodynamics from holography\nby Akhil Sivakum
ar (ICTS) as part of APCTP String Seminars\n\n\nAbstract\nAdS/CFT duality
implies that certain large N strongly coupled Conformal Field Theories hav
e an alternate description as weakly coupled gravitational theories. The f
luid-gravity correspondence is a well studied implication of the duality -
the hydrodynamic excitations of a holographic plasma are related to the l
ong-lived quasinormal modes of the dual blackbrane. We revisit this old pr
oblem from the perspective of the Open Effective Field Theory of the simme
ring hydrodynamic modes. The analysis relies on a novel gravitational sadd
le to evaluate real-time correlators which is crucial to correctly account
for the Hawking fluctuations of the blackbrane in addition to the dissipa
tive quasinormal modes.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joydeep Chakravarty (ICTS)
DTSTART:20211221T060000Z
DTEND:20211221T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/8
DESCRIPTION:Title: Toy models for monogamy and bags of gold paradoxes\nby Joyd
eep Chakravarty (ICTS) as part of APCTP String Seminars\n\n\nAbstract\nIn
this talk\, we will address some puzzles about the black hole interior fro
m the bulk perspective using toy models. We will discuss a toy model in em
pty flat space which captures essential features of the monogamy paradox f
or flat space black holes within a clean calculational framework. We will
also discuss how black holes in AdS can host an enormous number of semicla
ssical excitations in their interior\, which is seemingly not reflected in
the Bekenstein Hawking entropy.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masataka Watanabe (Weizmann Institute of Science)
DTSTART:20211229T060000Z
DTEND:20211229T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/9
DESCRIPTION:Title: Non-perturbative corrections to the large charge expansion\
nby Masataka Watanabe (Weizmann Institute of Science) as part of APCTP Str
ing Seminars\n\n\nAbstract\nPhysical quantities of theories with a global
symmetry can be computed in the $1/Q$ (inverse charge) expansion\, in a co
ntrolled fashion. This is true even when the theory is strongly-coupled\,
and I will first give you a reasoning for this using effective field theor
y. As an example\, we will use the $O(2)$ Wilson-Fisher theory in 3 dimens
ions\, and compute the operator dimension of $\\phi^Q$.\n\nSecond\, I will
combine the method with the epsilon expansion\, and reproduce the result
of the EFT. I also argue that there is an interesting double scaling limit
$\\epsilon\\cdot Q=\\text{const}$\, with $\\epsilon$ small and $Q$ large\
, which also reproduces the Feynman diagram computation when the double-sc
aling parameter is small.\n\nLastly\, I will discuss non-perturbative corr
ections to the formula. There\, I will mostly speak about Wilson-Fisher th
eory in $D=4+\\epsilon$ dimensions\, instead of $D=4-\\epsilon$\, where we
will compute the leading imaginary part of the operator dimension. I will
also make a very preliminary comment about resurgence in this double-scal
ing limit.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongsheng Ge (University of Warsaw)
DTSTART:20211228T060000Z
DTEND:20211228T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/10
DESCRIPTION:Title: Holographic Path-Integral Optimisation\nby Dongsheng Ge (U
niversity of Warsaw) as part of APCTP String Seminars\n\n\nAbstract\nIn th
is talk\, I will talk about the work arXiv:2104.00010. There\, we elaborat
e on holographic description of the path-integral optimization in conforma
l field theories (CFT) using Hartle-Hawking wave functions in Anti-de Sitt
er spacetimes. We argue that the maximization of the Hartle-Hawking wave f
unction is equivalent to the path-integral optimization procedure in CFT.
In particular\, we show that metrics that maximize gravity wave functions
computed in particular holographic geometries\, precisely match those deri
ved in the path-integral optimization procedure for their dual CFT states.
The present work contains many examples such as analysis of excited state
s in various dimensions including JT gravity\, and a new way of estimating
holographic path-integral complexity from Hartle-Hawking wave functions.
Finally\, we generalize the analysis to Lorentzian Anti-de Sitter and de S
itter geometries and use it to shed light on path-integral optimization in
Lorentzian CFTs.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chanju Kim (Ewha Womans University)
DTSTART:20211230T060000Z
DTEND:20211230T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/11
DESCRIPTION:Title: Supersymmetric Inhomogeneous Field Theories in 1+1 Dimensions<
/a>\nby Chanju Kim (Ewha Womans University) as part of APCTP String Semina
rs\n\n\nAbstract\nWe study supersymmetric inhomogeneous field theories in
1+1 dimensions which have explicit coordinate dependence. Although transla
tion symmetry is broken\, part of supersymmetries can be maintained. We co
nsider the simplest in-homogeneous theories with one real scalar field\, w
hich possess an unbroken super-symmetry. The energy is bounded from below
by the topological charge which is not necessarily nonnegative definite. T
he bound is saturated if the first-order Bogomolny equation is satisfied.
Non-constant static supersymmetric solutions above the vacuum involve in g
eneral a zero mode although the system lacks translation invariance. We co
nsider two inhomogeneous theories obtained by deforming supersymmetric sin
e-Gordon theory and phi^6 theory. They are deformed either by overall inho
mogeneous rescaling of the superpotential or by inhomogeneous deformation
of the vacuum expectation value. We construct explicitly the most general
supersymmetric solutions and obtain the BPS energy spectrum for arbitrary
position-dependent deformations. Nature of the solutions and their energie
s depend only on the boundary values of the inhomogeneous functions. The v
acuum of minimum energy is not necessarily a constant configuration. In so
me cases\, we find a one-parameter family of degenerate solutions which in
clude a non-vacuum constant solution as a special case.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anurag Kaushal (Tata Institute of Fundamental Research)
DTSTART:20220104T070000Z
DTEND:20220104T080000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/12
DESCRIPTION:Title: Bulk Geometry and Target Space Entanglement\nby Anurag Kau
shal (Tata Institute of Fundamental Research) as part of APCTP String Semi
nars\n\n\nAbstract\nMotivated by the Bekenstein-Hawking entropy and the ar
ea law behaviour of entanglement entropy\, we propose that in a UV finite
theory of quantum gravity with a smooth spacetime\, the total entropy for
a pure state in a co-dimension one spatial region\, to leading order\, is
given by $S=A/4G$. In the context of Dp-brane holography ($p<3$) we show t
hat for specially chosen regions bulk entanglement can be mapped to ‘tar
get space’ entanglement in the D-brane Yang Mills theory. We provide a g
auge-invariant characterization of operator sub-algebras corresponding to
such entanglement by finding a projection operator which imposes the const
raint characterizing the target space region of interest. Our conjecture l
eads to a precise proposal for target space entanglement at strong couplin
g and large N\, in particular that it would scale like $O(N^2)$. Recent nu
merical advances in the D0 brane system hold out the hope that this propos
al can be tested in a precise way. Based on [2004.00613] and [2011.13857]
with Sumit Das\, Sinong Liu\, Gautam Mandal & Sandip Trivedi.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenbin Yang (Stanford University)
DTSTART:20220502T020000Z
DTEND:20220502T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/13
DESCRIPTION:Title: Late time behavior of OTOC\nby Zhenbin Yang (Stanford Univ
ersity) as part of APCTP String Seminars\n\n\nAbstract\nIn this talk\, we
will discuss the late time behavior of out of time ordered correlators (OT
OC). First part of the talk\, we argue the nonlinear behavior of OTOC for
general chaotic system is controlled by a Dray t’Hooft like action. Seco
nd part of the talk\, we will discuss the late time nonperturbative effect
s in OTOC and its relation with random unitary behavior.\n\nBased on recen
t work: arxiv:2107.10252\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ying Zhao (KITP)
DTSTART:20220504T020000Z
DTEND:20220504T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/14
DESCRIPTION:Title: Collisions of localized shocks and quantum circuits\nby Yi
ng Zhao (KITP) as part of APCTP String Seminars\n\n\nAbstract\nWe study co
llisions between localized shockwaves inside a black hole interior. We giv
e a holographic boundary description of this process in terms of the overl
ap of two growing perturbations in a shared quantum circuit. The perturbat
ions grow both exponentially as well as ballistically. Due to a competitio
n between different physical effects\, the circuit analysis shows dependen
ce on the transverse locations and exhibits four regimes of qualitatively
different behaviors. On the gravity side we study properties of the post-c
ollision geometry\, using exact calculations in simple setups and estimati
ons in more general circumstances. We show that the circuit analysis offer
s intuitive and surprisingly accurate predictions about gravity computatio
ns involving non-linear features of general relativity.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steve Carlip (UC Davis)
DTSTART:20220509T020000Z
DTEND:20220509T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/15
DESCRIPTION:Title: A Schwarzian on the Stretched Horizon\nby Steve Carlip (UC
Davis) as part of APCTP String Seminars\n\n\nAbstract\nIt is well known t
hat the Euclidean black hole action has a boundary term at the horizon pro
portional to the area. I show that if the horizon is replaced by a stretch
ed horizon with appropriate boundary conditions\, a new boundary term appe
ars\, described by a Schwarzian action similar to the recently discovered
boundary actions in "nearly anti-de Sitter" gravity.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arnab Kundu (Saha University)
DTSTART:20220426T060000Z
DTEND:20220426T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/16
DESCRIPTION:Title: RG-flows\, TFD-states and Black Holes in AdS\nby Arnab Kun
du (Saha University) as part of APCTP String Seminars\n\n\nAbstract\nIn th
is talk we will discuss our recent work on the potential relation between
the interior of a black hole in AdS and an analytic continuation of the RG
-flow of the corresponding thermal state in the dual CFT. In particular\,
we will propose a measure for the central charge function and discuss how
this analytic continuation\, which is dubbed as "trans-IR flow"\, captures
a thinning out of degrees of freedom as one approaches the singularity of
the black hole interior. We will also discuss a specific UV-complete mode
l within type IIB supergravity in which these details can be better fleshe
d out.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edwan Preau (APC Paris)
DTSTART:20220503T060000Z
DTEND:20220503T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/17
DESCRIPTION:Title: Holographic baryon in the Veneziano limit\nby Edwan Preau
(APC Paris) as part of APCTP String Seminars\n\n\nAbstract\nThe holographi
c method is one of the only ways of getting analytic insight into most str
ongly coupled systems. When numerical methods are not available\, it is ev
en the best technique we know of to tackle these problems. In particular\,
lattice QCD is unable to provide results at finite baryon density\, which
is why a lot of effort is put into the study of holographic QCD at high d
ensity. Densities beyond the nuclear density are not only a theoretical fr
ontier\, but are reached in real systems such as neutron star cores and fu
ture heavy ion collision experiments. In this talk I will discuss the most
elementary aspect of baryonic physics in holography\, that is the study o
f a single baryon state. I will start by reviewing the qualitative feature
s of holographic baryons\, obtained already in models where the back-react
ion of quarks on the glue sector of QCD is neglected. I will then discuss
the consequences of introducing flavor back-reaction and finally present o
ur recent work in the framework of the V-QCD model\, which is the most com
plete holographic model of QCD.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Berenstein (UC Santa Barbara)
DTSTART:20220524T060000Z
DTEND:20220524T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/18
DESCRIPTION:Title: Aspects of holography in conical $AdS_3$\nby David Berenst
ein (UC Santa Barbara) as part of APCTP String Seminars\n\n\nAbstract\nI w
ill describe a model of a very localized heavy particle in AdS in 2+1 dime
nsions. The geometry associated to the particle is a conical defect in AdS
\, below the threshold for black hole.\nIn the presence of this particle
I explain how two point functions of boundary operators can be computed\,
special cases where the calculation can be made by the method of images a
nd various applications to the problem of bound states\, response function
s and critical behavior near the BTZ threshold transition.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Ferko (UC Davis)
DTSTART:20220628T020000Z
DTEND:20220628T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/19
DESCRIPTION:Title: TTbar Deformations in JT Gravity and BF Gauge Theory\nby C
hristian Ferko (UC Davis) as part of APCTP String Seminars\n\n\nAbstract\n
The TTbar operator provides a universal irrelevant deformation of two-dime
nsional quantum field theories with remarkable properties\, including conn
ections to string theory and various holographic interpretations in 3d gra
vity. By dimensional reduction\, one can likewise consider a TTbar-like de
formation of a (0+1)-dimensional quantum mechanics\, which is dual to a 2d
JT gravity theory or equivalently a 2d BF gauge theory. In this talk\, we
will describe the effect of such a TTbar-like deformation from the bulk p
erspective\, which corresponds to a particular state-dependent modificatio
n of the boundary conditions for the JT or BF fields. We will also discuss
corrections to observables like boundary-anchored Wilson lines in the pre
sence of such deformations.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Banks (Rutgers University)
DTSTART:20220802T020000Z
DTEND:20220802T030000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/20
DESCRIPTION:Title: Quantum Theory of the Low Energy States of Extremal Reissner N
ordstrom black holes of Large Charge\, or\, JT gravity coupled to fermions
\nby Thomas Banks (Rutgers University) as part of APCTP String Seminar
s\n\n\nAbstract\nWe construct a finite quantum theory that can describe bo
th equilibrium and transient non-equilibrium states of a non-supersymmetri
c extremal RN black hole. The model uses two well known dualities: the d
uality between matrix quantum mechanics and non-relativistic fermions in a
potential\, and the Alexandrov Kazakov Kostov duality between the latter
system and relativistic Weyl fermions. The physics of the model is that th
e geometry is a frozen $AdS_2$ background\, in a coordinate system where o
ne of the non-compact generators of $SL(2\,R)$ is preserved. The dilaton
field breaks the other two generators. Relativistic fermions in this back
ground have equilibrium states with all fermions clustered near the Killin
g horizon of the Hamiltonian\, and transient non-equilibrium states where
fermions or coherent states of their bosonized currents propagate out to t
he boundary at infinity and return to equilibrium. The dualities enable u
s to construct a system which has finite entropy and a chaotic spectrum\,
expected from general considerations in quantum gravity\, but can accurate
ly reproduce much of the behavior of field theory in the $AdS_2$ backgroun
d.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takashi Tsuda (YITP)
DTSTART:20221005T060000Z
DTEND:20221005T070000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/21
DESCRIPTION:Title: Free fermion cyclic/symmetric orbifold CFTs and its calculatio
ns for entanglement entropy\nby Takashi Tsuda (YITP) as part of APCTP
String Seminars\n\n\nAbstract\nWe study the properties of two-dimensional
CFTs defined by cyclic and \nsymmetric orbifolds of free Dirac fermions\,
especially by focusing on \nthe partition function and entanglement entro
py. \nIn the first half of this seminar\, we review symmetric/cyclic orbif
old \nCFTs and propose their connections. We provide the structure of twis
ted \nsectors in each theory and show that a similar structure appears. \n
In the latter half\, we start by reviewing bosonization and the replica \n
method on the ordinary Dirac fermion. Then we move on to explain our \ncal
culations: bosonizing the orbifold CFT and calculating physical \nquantiti
es. We compute the entanglement entropy and Renyi entropy in \ncyclic orbi
folds. We find that the replica method calculation is highly \nnon-trivial
and new because of the contributions from replicas with \ndifferent bound
ary conditions. \nAs a conclusion of this seminar\, we discuss extensions
of our results on \nentanglement entropy to symmetric orbifold CFTs and ma
ke a heuristic \nargument toward holographic CFTs.\nThis seminar is based
on arXiv:2209.00206.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noah Miller (Harvard University)
DTSTART:20221006T010000Z
DTEND:20221006T020000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/22
DESCRIPTION:Title: The Soft Graviton Theorem in the BFSS Matrix Model\nby Noa
h Miller (Harvard University) as part of APCTP String Seminars\n\n\nAbstra
ct\nIn this talk\, we will first briefly review the relationship between a
symptotic symmetries ("supertranslations") and the soft graviton theorem.
We will then review the BFSS matrix model\, which is 0+1 dimensional quant
um mechanical model of infinite dimensional matrices which was conjectured
in 1996 to be equivalent to M theory in flat 11 dimensional flat spacetim
e. The BFSS matrix model describes the non-relativistic quantum mechanics
of D0 branes moving in 9 transverse spatial dimensions. Because M theory r
educes to supergravity in its low energy limit\, it contains soft graviton
s and supertranslations as its symmetries. We then seek to address the que
stion of how soft gravitons and asymptotic symmetries are embedded in the
matrix model. We find that supertranslations live in the matrix model as l
arge gauge transformations of a background $C_\\mu$ 1-form field.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Renann Lipinski Jusinskas (Institute of Physics of the Czech Acade
my of Sciences)
DTSTART:20220927T070000Z
DTEND:20220927T080000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/23
DESCRIPTION:Title: Perturbiner methods in flat and curved spacetimes\nby Rena
nn Lipinski Jusinskas (Institute of Physics of the Czech Academy of Scienc
es) as part of APCTP String Seminars\n\n\nAbstract\nThe perturbiner method
is a compact tool to derive the so-called Berends-Giele currents\, theref
ore establishing an elegant recursive method for computing scattering ampl
itudes. It does so via formal multiparticle solutions of classical equatio
ns of motion. In this talk I will introduce these solutions in a couple of
simple examples and show how they can be used to compute one-loop integra
nds and tree-level correlators in (Anti) de Sitter.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin David (IISc\, Bangalore)
DTSTART:20221024T063000Z
DTEND:20221024T073000Z
DTSTAMP:20260404T094319Z
UID:APCTPstring/24
DESCRIPTION:Title: Entanglement properties of the graviton\nby Justin David (
IISc\, Bangalore) as part of APCTP String Seminars\n\n\nAbstract\nThe enta
nglement properties of the spin-2 field have only been recently studied.\n
We present some results for the entanglement properties of the linearised
graviton in 4 dimensions.\nThe coefficient of the logarithmic term in th
e entanglement of gravitons across a spherical surface\ncontains a class
ical contribution due to the Gauss law in gravity. \nWe present the detail
s of how this classical contribution is evaluated and how the result is co
nsistent\nwith recent observations of edge partition functions of graviton
s on the 4-sphere. \nIf time permits\, we briefly discuss the time depende
nt behaviour of entanglement entropy \nquantum quenches due to curvature e
xcitations.\n
LOCATION:https://stable.researchseminars.org/talk/APCTPstring/24/
END:VEVENT
END:VCALENDAR