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BEGIN:VEVENT
SUMMARY:Sourav Roychowdhury (Chennai Mathematical Institute)
DTSTART:20211123T060000Z
DTEND:20211123T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/1
DESCRIPTION:Title: Non-Abelian T-dual of Klebanov-Tseytlin background and its Penrose lim
its\nby Sourav Roychowdhury (Chennai Mathematical Institute) as part o
f APCTP String Seminars\n\n\nAbstract\nIn this talk I will discuss Klebano
v-Tseytlin background and it’s non-Abelian T-dual ge- ometry. In particu
lar I will show that the T-dual background admits pp-wave geometry in the
neighbourhood of appropriate null geodesic. I will make comments on possib
le dual gauge theory for our pp-wave background.\n\nZOOM Link: https://us0
6web.zoom.us/meeting/register/tZItc-ispz4jHtdDWcjdm34TnKq3rg-a5U8s\n\n※
You can join 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 the meeting\, please rename your profile as your full name (affi
liation) *E.g. Gildong Hong (APCTP)\n
LOCATION:https://researchseminars.org/talk/APCTPstring/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211125T050000Z
DTEND:20211125T060000Z
DTSTAMP:20260422T212527Z
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\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://researchseminars.org/talk/APCTPstring/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211126T010000Z
DTEND:20211126T020000Z
DTSTAMP:20260422T212527Z
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\nCoadj
oint orbits of Lie group and its quantizations have various interesting ap
plications in physics. In the first lecture\, I will introduce them within
the context of higher spin gravity. In the second and third lectures\, it
s relation to dual pair correspondence and the relevant representation the
ory analysis will be discussed.\n\nZOOM Link: https://us06web.zoom.us/meet
ing/register/tZItd-muqDsuGNEqRDTd6p5K-3dHgeBm-acl\n\n※ You can join the
webinar with a link generated after the registration.\n※ In the case tha
t a passcode is required to join\, type 0000.\n※ When entering the meeti
ng\, please rename your profile as your full name (affiliation) *E.g. G
ildong Hong (APCTP)\n
LOCATION:https://researchseminars.org/talk/APCTPstring/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Euihun Joung (Kyunghee University)
DTSTART:20211126T020000Z
DTEND:20211126T030000Z
DTSTAMP:20260422T212527Z
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\nAbstract\nCoad
joint orbits of Lie group and its quantizations have various interesting a
pplications in physics. In the first lecture\, I will introduce them withi
n the context of higher spin gravity. In the second and third lectures\, i
ts relation to dual pair correspondence and the relevant representation th
eory analysis will be discussed.\n\nZOOM Link: https://us06web.zoom.us/mee
ting/register/tZItd-muqDsuGNEqRDTd6p5K-3dHgeBm-acl\n\n※ You can join the
webinar with a link generated after the registration.\n※ In the case th
at a passcode is required to join\, type 0000.\n※ When entering the meet
ing\, please rename your profile as your full name (affiliation) *E.g.
Gildong Hong (APCTP)\n
LOCATION:https://researchseminars.org/talk/APCTPstring/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hyojoong Kim (Kyunghee University)
DTSTART:20211207T060000Z
DTEND:20211207T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/5
DESCRIPTION:Title: On the Superconformal Index of Chern-Simons theories and their KK Spec
trometry\nby Hyojoong Kim (Kyunghee University) as part of APCTP Strin
g Seminars\n\n\nAbstract\nWe study the large-$N$ limit of superconformal i
ndex for two strongly interacting Chern-Simons theories in three dimension
s with $\\mathcal{N} = 2$ supersymmetry\, and compare the result against t
he AdS/CFT dual\, namely the data of full Kaluza-Klein reduction spectra o
btained using the exceptional field theory technique. The two theories of
interest are mABJM and GJV theories\, which are obtained as IR fixed point
of RG whose UV description is ABJM and maximally supersymmetric Yang-Mill
s theory respectively. We confirm agreement and the duality persists. For
the case of mABJM it turns out that we need a refinement of the gravity in
dex which reflects the fact that the UV description on the field theory si
de has enhanced global symmetry.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Binata Panda (ISM)
DTSTART:20211124T060000Z
DTEND:20211124T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/6
DESCRIPTION:Title: Seeley DeWitt Coefficients and Logarithmic entropy corrections for bla
ck holes in generalized Einstein-Maxwell theory\nby Binata Panda (ISM)
as part of APCTP String Seminars\n\n\nAbstract\nLogarithmic corrections t
o the entropy of different classes of black holes are interesting to study
in the context of testing a quantum theory of gravity. These are special
quantum corrections that are universal\, most dominant\, and entirely com
putable from low energy data (i.e.\, massless fluctuations and their coupl
ing to the black hole background). Euclidean gravity approach has been suc
cessful in computing these corrections to extremal and non-extremal black
hole entropy. One of the important ingredients for this approach is to cal
culate the Seeley-DeWitt coefficients of the kinetic operator of the massl
ess fields in the black hole background. In this talk\, we will discuss t
he computation of Seeley-DeWitt coefficients as well as the logarithmic co
rrections to the entropy of black holes in a generalized Einstein-Maxwell
theory (minimally coupled to arbitrary numbers of additional massless scal
ar\, vector\, spin-1/2\, and spin-3/2 fields).\n\nZOOM Link: https://us06
web.zoom.us/meeting/register/tZMlc-CvrT4tHNGL7v7TQqFV-5Tg14foC0gx\n\n※ Y
ou can join the webinar with a link generated after the registration.\n※
In the case that a passcode is required to join\, type 0000.\n※ When en
tering the meeting\, please rename your profile as your full name (affilia
tion) *E.g. Gildong Hong (APCTP)\n
LOCATION:https://researchseminars.org/talk/APCTPstring/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Akhil Sivakumar (ICTS)
DTSTART:20211222T060000Z
DTEND:20211222T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/7
DESCRIPTION:Title: Fluctuating Hydrodynamics from holography\nby Akhil Sivakumar (ICT
S) as part of APCTP String Seminars\n\n\nAbstract\nAdS/CFT duality implies
that certain large N strongly coupled Conformal Field Theories have an al
ternate description as weakly coupled gravitational theories. The fluid-gr
avity correspondence is a well studied implication of the duality - the hy
drodynamic excitations of a holographic plasma are related to the long-liv
ed quasinormal modes of the dual blackbrane. We revisit this old problem f
rom the perspective of the Open Effective Field Theory of the simmering hy
drodynamic modes. The analysis relies on a novel gravitational saddle to e
valuate real-time correlators which is crucial to correctly account for th
e Hawking fluctuations of the blackbrane in addition to the dissipative qu
asinormal modes.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joydeep Chakravarty (ICTS)
DTSTART:20211221T060000Z
DTEND:20211221T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/8
DESCRIPTION:Title: Toy models for monogamy and bags of gold paradoxes\nby Joydeep Cha
kravarty (ICTS) as part of APCTP String Seminars\n\n\nAbstract\nIn this ta
lk\, we will address some puzzles about the black hole interior from the b
ulk perspective using toy models. We will discuss a toy model in empty fla
t space which captures essential features of the monogamy paradox for flat
space black holes within a clean calculational framework. We will also di
scuss how black holes in AdS can host an enormous number of semiclassical
excitations in their interior\, which is seemingly not reflected in the Be
kenstein Hawking entropy.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masataka Watanabe (Weizmann Institute of Science)
DTSTART:20211229T060000Z
DTEND:20211229T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/9
DESCRIPTION:Title: Non-perturbative corrections to the large charge expansion\nby Mas
ataka Watanabe (Weizmann Institute of Science) as part of APCTP String Sem
inars\n\n\nAbstract\nPhysical quantities of theories with a global symmetr
y can be computed in the $1/Q$ (inverse charge) expansion\, in a controlle
d fashion. This is true even when the theory is strongly-coupled\, and I w
ill first give you a reasoning for this using effective field theory. As a
n example\, we will use the $O(2)$ Wilson-Fisher theory in 3 dimensions\,
and compute the operator dimension of $\\phi^Q$.\n\nSecond\, I will combin
e the method with the epsilon expansion\, and reproduce the result of the
EFT. I also argue that there is an interesting double scaling limit $\\eps
ilon\\cdot Q=\\text{const}$\, with $\\epsilon$ small and $Q$ large\, which
also reproduces the Feynman diagram computation when the double-scaling p
arameter is small.\n\nLastly\, I will discuss non-perturbative corrections
to the formula. There\, I will mostly speak about Wilson-Fisher theory in
$D=4+\\epsilon$ dimensions\, instead of $D=4-\\epsilon$\, where we will c
ompute the leading imaginary part of the operator dimension. I will also m
ake a very preliminary comment about resurgence in this double-scaling lim
it.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dongsheng Ge (University of Warsaw)
DTSTART:20211228T060000Z
DTEND:20211228T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/10
DESCRIPTION:Title: Holographic Path-Integral Optimisation\nby Dongsheng Ge (Universi
ty of Warsaw) as part of APCTP String Seminars\n\n\nAbstract\nIn this talk
\, I will talk about the work arXiv:2104.00010. There\, we elaborate on ho
lographic description of the path-integral optimization in conformal field
theories (CFT) using Hartle-Hawking wave functions in Anti-de Sitter spac
etimes. We argue that the maximization of the Hartle-Hawking wave function
is equivalent to the path-integral optimization procedure in CFT. In part
icular\, we show that metrics that maximize gravity wave functions compute
d in particular holographic geometries\, precisely match those derived in
the path-integral optimization procedure for their dual CFT states. The pr
esent work contains many examples such as analysis of excited states in va
rious dimensions including JT gravity\, and a new way of estimating hologr
aphic path-integral complexity from Hartle-Hawking wave functions. Finally
\, we generalize the analysis to Lorentzian Anti-de Sitter and de Sitter g
eometries and use it to shed light on path-integral optimization in Lorent
zian CFTs.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chanju Kim (Ewha Womans University)
DTSTART:20211230T060000Z
DTEND:20211230T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/11
DESCRIPTION:Title: Supersymmetric Inhomogeneous Field Theories in 1+1 Dimensions\nby
Chanju Kim (Ewha Womans University) as part of APCTP String Seminars\n\n\
nAbstract\nWe study supersymmetric inhomogeneous field theories in 1+1 dim
ensions which have explicit coordinate dependence. Although translation sy
mmetry is broken\, part of supersymmetries can be maintained. We consider
the simplest in-homogeneous theories with one real scalar field\, which po
ssess an unbroken super-symmetry. The energy is bounded from below by the
topological charge which is not necessarily nonnegative definite. The boun
d is saturated if the first-order Bogomolny equation is satisfied. Non-con
stant static supersymmetric solutions above the vacuum involve in general
a zero mode although the system lacks translation invariance. We consider
two inhomogeneous theories obtained by deforming supersymmetric sine-Gordo
n theory and phi^6 theory. They are deformed either by overall inhomogeneo
us rescaling of the superpotential or by inhomogeneous deformation of the
vacuum expectation value. We construct explicitly the most general supersy
mmetric solutions and obtain the BPS energy spectrum for arbitrary positio
n-dependent deformations. Nature of the solutions and their energies depen
d only on the boundary values of the inhomogeneous functions. The vacuum o
f minimum energy is not necessarily a constant configuration. In some case
s\, we find a one-parameter family of degenerate solutions which include a
non-vacuum constant solution as a special case.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anurag Kaushal (Tata Institute of Fundamental Research)
DTSTART:20220104T070000Z
DTEND:20220104T080000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/12
DESCRIPTION:Title: Bulk Geometry and Target Space Entanglement\nby Anurag Kaushal (T
ata Institute of Fundamental Research) as part of APCTP String Seminars\n\
n\nAbstract\nMotivated by the Bekenstein-Hawking entropy and the area 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 b
y $S=A/4G$. In the context of Dp-brane holography ($p<3$) we show that for
specially chosen regions bulk entanglement can be mapped to ‘target spa
ce’ entanglement in the D-brane Yang Mills theory. We provide a gauge-in
variant characterization of operator sub-algebras corresponding to such en
tanglement by finding a projection operator which imposes the constraint c
haracterizing the target space region of interest. Our conjecture leads to
a precise proposal for target space entanglement at strong coupling and l
arge N\, in particular that it would scale like $O(N^2)$. Recent numerical
advances in the D0 brane system hold out the hope that this proposal can
be tested in a precise way. Based on [2004.00613] and [2011.13857] with Su
mit Das\, Sinong Liu\, Gautam Mandal & Sandip Trivedi.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenbin Yang (Stanford University)
DTSTART:20220502T020000Z
DTEND:20220502T030000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/13
DESCRIPTION:Title: Late time behavior of OTOC\nby Zhenbin Yang (Stanford University)
as part of APCTP String Seminars\n\n\nAbstract\nIn this talk\, we will di
scuss the late time behavior of out of time ordered correlators (OTOC). Fi
rst part of the talk\, we argue the nonlinear behavior of OTOC for general
chaotic system is controlled by a Dray t’Hooft like action. Second part
of the talk\, we will discuss the late time nonperturbative effects in OT
OC and its relation with random unitary behavior.\n\nBased on recent work:
arxiv:2107.10252\n
LOCATION:https://researchseminars.org/talk/APCTPstring/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ying Zhao (KITP)
DTSTART:20220504T020000Z
DTEND:20220504T030000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/14
DESCRIPTION:Title: Collisions of localized shocks and quantum circuits\nby Ying Zhao
(KITP) as part of APCTP String Seminars\n\n\nAbstract\nWe study collision
s between localized shockwaves inside a black hole interior. We give a hol
ographic boundary description of this process in terms of the overlap of t
wo growing perturbations in a shared quantum circuit. The perturbations gr
ow both exponentially as well as ballistically. Due to a competition betwe
en different physical effects\, the circuit analysis shows dependence on t
he transverse locations and exhibits four regimes of qualitatively differe
nt behaviors. On the gravity side we study properties of the post-collisio
n geometry\, using exact calculations in simple setups and estimations in
more general circumstances. We show that the circuit analysis offers intui
tive and surprisingly accurate predictions about gravity computations invo
lving non-linear features of general relativity.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steve Carlip (UC Davis)
DTSTART:20220509T020000Z
DTEND:20220509T030000Z
DTSTAMP:20260422T212527Z
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 that the
Euclidean black hole action has a boundary term at the horizon proportion
al to the area. I show that if the horizon is replaced by a stretched hori
zon with appropriate boundary conditions\, a new boundary term appears\, d
escribed by a Schwarzian action similar to the recently discovered boundar
y actions in "nearly anti-de Sitter" gravity.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arnab Kundu (Saha University)
DTSTART:20220426T060000Z
DTEND:20220426T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/16
DESCRIPTION:Title: RG-flows\, TFD-states and Black Holes in AdS\nby Arnab Kundu (Sah
a University) as part of APCTP String Seminars\n\n\nAbstract\nIn this talk
we will discuss our recent work on the potential relation between the int
erior of a black hole in AdS and an analytic continuation of the RG-flow o
f the corresponding thermal state in the dual CFT. In particular\, we will
propose a measure for the central charge function and discuss how this an
alytic continuation\, which is dubbed as "trans-IR flow"\, captures a thin
ning out of degrees of freedom as one approaches the singularity of the bl
ack hole interior. We will also discuss a specific UV-complete model withi
n type IIB supergravity in which these details can be better fleshed out.\
n
LOCATION:https://researchseminars.org/talk/APCTPstring/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edwan Preau (APC Paris)
DTSTART:20220503T060000Z
DTEND:20220503T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/17
DESCRIPTION:Title: Holographic baryon in the Veneziano limit\nby Edwan Preau (APC Pa
ris) as part of APCTP String Seminars\n\n\nAbstract\nThe holographic metho
d is one of the only ways of getting analytic insight into most strongly c
oupled systems. When numerical methods are not available\, it is even the
best technique we know of to tackle these problems. In particular\, lattic
e 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 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 he
avy ion collision experiments. In this talk I will discuss the most elemen
tary aspect of baryonic physics in holography\, that is the study of a sin
gle baryon state. I will start by reviewing the qualitative features of ho
lographic baryons\, obtained already in models where the back-reaction of
quarks on the glue sector of QCD is neglected. I will then discuss the con
sequences of introducing flavor back-reaction and finally present our rece
nt work in the framework of the V-QCD model\, which is the most complete h
olographic model of QCD.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Berenstein (UC Santa Barbara)
DTSTART:20220524T060000Z
DTEND:20220524T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/18
DESCRIPTION:Title: Aspects of holography in conical $AdS_3$\nby David Berenstein (UC
Santa Barbara) as part of APCTP String Seminars\n\n\nAbstract\nI will des
cribe a model of a very localized heavy particle in AdS in 2+1 dimensions.
The geometry associated to the particle is a conical defect in AdS\, belo
w the threshold for black hole.\nIn the presence of this particle I expla
in how two point functions of boundary operators can be computed\, specia
l cases where the calculation can be made by the method of images and vari
ous applications to the problem of bound states\, response functions and c
ritical behavior near the BTZ threshold transition.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Ferko (UC Davis)
DTSTART:20220628T020000Z
DTEND:20220628T030000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/19
DESCRIPTION:Title: TTbar Deformations in JT Gravity and BF Gauge Theory\nby Christia
n Ferko (UC Davis) as part of APCTP String Seminars\n\n\nAbstract\nThe TTb
ar operator provides a universal irrelevant deformation of two-dimensional
quantum field theories with remarkable properties\, including connections
to string theory and various holographic interpretations in 3d gravity. B
y dimensional reduction\, one can likewise consider a TTbar-like deformati
on of a (0+1)-dimensional quantum mechanics\, which is dual to a 2d JT gra
vity theory or equivalently a 2d BF gauge theory. In this talk\, we will d
escribe the effect of such a TTbar-like deformation from the bulk perspect
ive\, which corresponds to a particular state-dependent modification of th
e boundary conditions for the JT or BF fields. We will also discuss correc
tions to observables like boundary-anchored Wilson lines in the presence o
f such deformations.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Banks (Rutgers University)
DTSTART:20220802T020000Z
DTEND:20220802T030000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/20
DESCRIPTION:Title: Quantum Theory of the Low Energy States of Extremal Reissner Nordstro
m black holes of Large Charge\, or\, JT gravity coupled to fermions\nb
y Thomas Banks (Rutgers University) as part of APCTP String Seminars\n\n\n
Abstract\nWe construct a finite quantum theory that can describe both equi
librium and transient non-equilibrium states of a non-supersymmetric extre
mal RN black hole. The model uses two well known dualities: the duality
between matrix quantum mechanics and non-relativistic fermions in a potent
ial\, and the Alexandrov Kazakov Kostov duality between the latter system
and relativistic Weyl fermions. The physics of the model is that the geome
try is a frozen $AdS_2$ background\, in a coordinate system where one of t
he non-compact generators of $SL(2\,R)$ is preserved. The dilaton field b
reaks the other two generators. Relativistic fermions in this background
have equilibrium states with all fermions clustered near the Killing horiz
on of the Hamiltonian\, and transient non-equilibrium states where fermion
s or coherent states of their bosonized currents propagate out to the boun
dary at infinity and return to equilibrium. The dualities enable us to co
nstruct a system which has finite entropy and a chaotic spectrum\, expecte
d from general considerations in quantum gravity\, but can accurately repr
oduce much of the behavior of field theory in the $AdS_2$ background.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Takashi Tsuda (YITP)
DTSTART:20221005T060000Z
DTEND:20221005T070000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/21
DESCRIPTION:Title: Free fermion cyclic/symmetric orbifold CFTs and its calculations for
entanglement entropy\nby Takashi Tsuda (YITP) as part of APCTP String
Seminars\n\n\nAbstract\nWe study the properties of two-dimensional CFTs d
efined by cyclic and \nsymmetric orbifolds of free Dirac fermions\, especi
ally by focusing on \nthe partition function and entanglement entropy. \nI
n the first half of this seminar\, we review symmetric/cyclic orbifold \nC
FTs and propose their connections. We provide the structure of twisted \ns
ectors in each theory and show that a similar structure appears. \nIn the
latter half\, we start by reviewing bosonization and the replica \nmethod
on the ordinary Dirac fermion. Then we move on to explain our \ncalculatio
ns: bosonizing the orbifold CFT and calculating physical \nquantities. We
compute the entanglement entropy and Renyi entropy in \ncyclic orbifolds.
We find that the replica method calculation is highly \nnon-trivial and ne
w because of the contributions from replicas with \ndifferent boundary con
ditions. \nAs a conclusion of this seminar\, we discuss extensions of our
results on \nentanglement entropy to symmetric orbifold CFTs and make a he
uristic \nargument toward holographic CFTs.\nThis seminar is based on arXi
v:2209.00206.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Noah Miller (Harvard University)
DTSTART:20221006T010000Z
DTEND:20221006T020000Z
DTSTAMP:20260422T212527Z
UID:APCTPstring/22
DESCRIPTION:Title: The Soft Graviton Theorem in the BFSS Matrix Model\nby Noah Mille
r (Harvard University) as part of APCTP String Seminars\n\n\nAbstract\nIn
this talk\, we will first briefly review the relationship between asymptot
ic symmetries ("supertranslations") and the soft graviton theorem. We will
then review the BFSS matrix model\, which is 0+1 dimensional quantum mech
anical model of infinite dimensional matrices which was conjectured in 199
6 to be equivalent to M theory in flat 11 dimensional flat spacetime. The
BFSS matrix model describes the non-relativistic quantum mechanics of D0 b
ranes moving in 9 transverse spatial dimensions. Because M theory reduces
to supergravity in its low energy limit\, it contains soft gravitons and s
upertranslations as its symmetries. We then seek to address the question o
f how soft gravitons and asymptotic symmetries are embedded in the matrix
model. We find that supertranslations live in the matrix model as large ga
uge transformations of a background $C_\\mu$ 1-form field.\n
LOCATION:https://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:20260422T212527Z
UID:APCTPstring/23
DESCRIPTION:Title: Perturbiner methods in flat and curved spacetimes\nby Renann Lipi
nski Jusinskas (Institute of Physics of the Czech Academy of Sciences) as
part of APCTP String Seminars\n\n\nAbstract\nThe perturbiner method is a c
ompact tool to derive the so-called Berends-Giele currents\, therefore est
ablishing an elegant recursive method for computing scattering amplitudes.
It does so via formal multiparticle solutions of classical equations of m
otion. 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 integrands and
tree-level correlators in (Anti) de Sitter.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin David (IISc\, Bangalore)
DTSTART:20221024T063000Z
DTEND:20221024T073000Z
DTSTAMP:20260422T212527Z
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 entanglemen
t properties of the spin-2 field have only been recently studied.\nWe pres
ent some results for the entanglement properties of the linearised gravito
n in 4 dimensions.\nThe coefficient of the logarithmic term in the enta
nglement of gravitons across a spherical surface\ncontains a classical co
ntribution due to the Gauss law in gravity. \nWe present the details of ho
w this classical contribution is evaluated and how the result is consisten
t\nwith recent observations of edge partition functions of gravitons on th
e 4-sphere. \nIf time permits\, we briefly discuss the time dependent beha
viour of entanglement entropy \nquantum quenches due to curvature excitati
ons.\n
LOCATION:https://researchseminars.org/talk/APCTPstring/24/
END:VEVENT
END:VCALENDAR