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BEGIN:VEVENT
SUMMARY:Sameer Murthy (Kings College London)
DTSTART;VALUE=DATE-TIME:20200526T120000Z
DTEND;VALUE=DATE-TIME:20200526T130000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/1
DESCRIPTION:Title: The growth of the 1/16-BPS index in N=4 Super Yang-Mills\nby Sam
eer Murthy (Kings College London) as part of CERN String Seminars\n\n\nAbs
tract\nI will discuss the superconformal index that counts states preservi
ng two supercharges in N=4 SYM\, and more generally in N=1 SCFTs\, on $S^3
$. This index is captured by a unitary matrix model with purely double tra
ce operators in the action. The AdS/CFT correspondence predicts that the i
ndex should have exponential growth at large charges and large N\, corresp
onding to the 1/16-BPS black hole (BH) in AdS5. I will present analytical
and numerical analyses of the matrix model which clearly show this expecte
d BH growth. In particular\, I will introduce a deformation of the matrix
model which allows us to solve it at large-N. The deformation has interest
ing relations with the Bloch-Wigner dilogarithm\, a function introduced by
number theorists. \nFinally\, using techniques from representation theory
\, I will show that the finite-N index actually interpolates between count
ing multi-gravitons at small charge and BHs at large charge.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Del Zotto
DTSTART;VALUE=DATE-TIME:20200616T120000Z
DTEND;VALUE=DATE-TIME:20200616T130000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/2
DESCRIPTION:Title: Higher form symmetries and M theory\nby Michele Del Zotto as par
t of CERN String Seminars\n\n\nAbstract\nWhat is the stringy origin of dis
crete higher form symmetries of quantum field theories? In this talk we wi
ll discuss the answer to this question in terms of defect groups from geom
etric engineering in M-theory. Flux non-commutativity in M-theory gives ri
se to (mixed) ’t Hooft anomalies for the defect group\, which constrains
the corresponding global structures of the associated quantum fields. Exa
mples of applications in various dimensions will be given\, with special e
mphasis on the case of 5d SCFTs.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Maloney
DTSTART;VALUE=DATE-TIME:20200623T140000Z
DTEND;VALUE=DATE-TIME:20200623T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/3
DESCRIPTION:Title: Gravity from Averaging CFTs\nby Alex Maloney as part of CERN Str
ing Seminars\n\n\nAbstract\nI will explore the idea that certain theories
of gravity in Anti-de\nSitter space are dual to an average over an ensembl
e of quantum\ntheories\, rather than to a specific quantum theory. I will
describe\nan average over Narain’s family of two-dimensional conformal
field\ntheories which describe free bosons on a torus\, and compute the\np
artition function using the Siegel-Weil formula. The result takes\nthe fo
rm of a sum over geometries as one would expect in a theory of\ngravity.
But the gravitational theory looks more like a Chern-Simons\ntheory than
like Einstein gravity.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Andriot
DTSTART;VALUE=DATE-TIME:20200707T130000Z
DTEND;VALUE=DATE-TIME:20200707T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/4
DESCRIPTION:Title: Do classical de Sitter string backgrounds exist?\nby David Andri
ot as part of CERN String Seminars\n\n\nAbstract\nA classical solution of
string theory with a 4d de Sitter space-time could provide a simple and we
ll-controlled setting to establish a connection to cosmological models. So
far however\, it has proven very difficult to find any example of such a
solution. As will be recalled\, attempts in this direction are plagued by
many no-go theorems\, or by the difficulty for concrete 10d supergravity s
olutions to fit in the classical stringy regime. This situation agrees wit
h the recent claims of de Sitter swampland conjectures. These conjectures
can actually be verified quantitatively\, with a surprisingly good agreeme
nt\, as will be shown. This may hint at a deep reason against classical de
Sitter background\, possibly to be found within the web of swampland conj
ectures\, and the relation to the distance conjecture will briefly be comm
ented on.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julian Sonner
DTSTART;VALUE=DATE-TIME:20200811T120000Z
DTEND;VALUE=DATE-TIME:20200811T130000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/5
DESCRIPTION:Title: Causal symmetry breaking: late time physics of holographic quantum c
haos\nby Julian Sonner as part of CERN String Seminars\n\n\nAbstract\n
Quantum chaotic systems are often defined via the assertion that their spe
ctral statistics coincides with\, or is well approximated by\, random matr
ix theory. In this talk I will explain how the universal content of random
matrix theory emerges as the consequence of a simple symmetry-breaking pr
inciple and its associated Goldstone modes. Within AdS/CFT this gives a un
iversal framework to express correlations between ``different universes’
’\, even for individual theories rather than ensembles. I will Illustrat
e the bulk picture of this EFT using the example minimal string theory. I
will end by discussing the construction of the EFT of quantum chaos also i
n higher dimensional field theories\, as applicable for example for higher
-dimensional AdS/CFT dual pairs.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jordan Cotler
DTSTART;VALUE=DATE-TIME:20200922T140000Z
DTEND;VALUE=DATE-TIME:20200922T160000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/6
DESCRIPTION:Title: Euclidean Wormholes and Random CFT\nby Jordan Cotler as part of
CERN String Seminars\n\n\nAbstract\nWe will nonperturbatively compute the
path integral of 3D gravity with negative cosmological constant on spaces
which are topologically a torus times an interval. These are Euclidean wor
mholes\, which smoothly interpolate between two asymptotically Euclidean A
dS3 regions with torus boundary. The resulting amplitude encodes spectral
correlations between BTZ black hole microstates near threshold. The low-
energy limit of these correlations is precisely that of a double-scaled ra
ndom matrix ensemble with Virasoro symmetry. These findings suggest that i
f pure 3D gravity has a holographic dual\, then the dual is an ensemble wh
ich generalizes random matrix theory. We will also show that there are an
alogs of these 3D wormholes in higher dimensions and discuss their stabili
ty in pure Einstein gravity as well as string theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero
DTSTART;VALUE=DATE-TIME:20200929T120000Z
DTEND;VALUE=DATE-TIME:20200929T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/7
DESCRIPTION:Title: Cobordisms\, anomalies\, and the Swampland in d>6\nby Miguel Mon
tero as part of CERN String Seminars\n\n\nAbstract\nThe Swampland program
aims at constraining the EFTs that can be consistently coupled to quantum
gravity from general principles. In particular cases\, absence of global s
ymmetries can lead to strong constraints at low energies. In this talk I w
ill explain how and illustrate this in the particular context of supersymm
etric theories in d>6. In particular\, vanishing of certain cobordism clas
ses requires existence of singular defects\, which we call "I-folds". I-fo
ld compactifications can have anomalies\, rendering the theory inconsisten
t. In this way\, we find additional constraints in the rank of the gauge g
roup in d>6. In d>7\, our constraints are very restrictive\, and the only
solutions are precisely realized by the known string compactifications to
8d and 9d. This establishes the "String Lamppost Principle"\, the idea tha
t the only consistent quantum gravities are string compactifications\, in
d>7 on a generic point of the Coulomb branch. I will also briefly comment
on applications of these techniques to other interesting setups.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Dodelson
DTSTART;VALUE=DATE-TIME:20201006T120000Z
DTEND;VALUE=DATE-TIME:20201006T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/8
DESCRIPTION:Title: Singularities of thermal correlators at strong coupling\nby Matt
hew Dodelson as part of CERN String Seminars\n\n\nAbstract\nI will describ
e work in progress with Ooguri on the singularities of the two point funct
ion at finite temperature in a conformal field theory in more than two dim
ensions. At weak coupling the only singularity is on the light cone\, but
in the large N\, large lambda regime a new singularity emerges. This new s
ingularity corresponds to a null geodesic in the AdS/Schwarzschild black h
ole\, which may wrap the photon sphere many times. After deriving this res
ult\, I will discuss the resolution of these singularities by stringy tida
l effects at finite lambda. The basic tool I will use is to take the Penro
se limit around a given null geodesic\, and then use the solubility of the
string theory in this background. I will also discuss applications to rot
ating black holes.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Craig Lawrie
DTSTART;VALUE=DATE-TIME:20201020T140000Z
DTEND;VALUE=DATE-TIME:20201020T160000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/9
DESCRIPTION:Title: Integrability in 6D SCFTs\nby Craig Lawrie as part of CERN Strin
g Seminars\n\n\nAbstract\n6D superconformal field theories associated to l
ong generalized quivers have a large R-charge sector\; we find evidence th
at operator mixing in this sector is governed by a 1D spin chain Hamiltoni
an with operator scaling dimensions controlled by a perturbation series in
inverse powers of the R-charge. When the 6D SCFT is rank R (G\, G) confor
mal matter we study a class of operators where the mixing is controlled by
the integrable open Heisenberg XXX_s spin chain\, with the spin s dependi
ng on the particular ADE-type of G. I will review the construction of such
6D SCFTs and how to build the large R-charge operators from the individua
l conformal matter building blocks\, derive the integrable Hamiltonian cap
turing the operator mixing\, determine the anomalous dimensions of one cla
ss of operators\, and give a variety of future directions in which the put
ative integrable structure of 6D SCFTs can be tested and explored.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou
DTSTART;VALUE=DATE-TIME:20201013T130000Z
DTEND;VALUE=DATE-TIME:20201013T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/10
DESCRIPTION:Title: Inside the Hologram: The bulk observer's experience\nby Lampros
Lamprou as part of CERN String Seminars\n\n\nAbstract\n"I will present a
holographic framework for reconstructing the experience of bulk observers
in AdS/CFT. In particular\, I will show how to recover the proper time and
energy distribution measured along bulk worldlines\, directly in the CFT
via a universal\, background-independent prescription. For an observer fal
ling into an eternal AdS black hole\, the proposal resolves a conceptual p
uzzle raised by Marolf and Wall. Notably\, the prescription does not rely
on an external dynamical Hamiltonian or the AdS boundary conditions and is
\, therefore\, outlining a general framework for the emergence of time."\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Johanna Erdmenger
DTSTART;VALUE=DATE-TIME:20201027T130000Z
DTEND;VALUE=DATE-TIME:20201027T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/11
DESCRIPTION:Title: Resolving the modular flow for free fermions\nby Johanna Erdmen
ger as part of CERN String Seminars\n\n\nAbstract\nModular flow is a symme
try of the algebra of observables associated to spacetime regions. It has
played a key role in recent connections between information theory\, QFT
and gravity. However\, little is known about its explicit action beyond hi
ghly symmetric cases. The key new element presented in this talk is a new
formula for modular flows for free chiral fermions in 1+1 dimensions. This
is obtained from the resolvent\, a standard technique in complex analysis
. We present novel results -- not fixed by conformal symmetry -- for disjo
int regions on the plane\, cylinder and torus. Depending on temperature an
d boundary conditions\, these display different behaviour ranging from pur
ely local to non-local in relation to the mixing of operators at spacelike
separation. We also discuss the modular two-point function\, whose analy
tic structure is in precise agreement with the KMS condition that governs
modular evolution. The ready-to-use formulae presented may provide new ing
redients to explore the connection between spacetime and entanglement.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Blommaert
DTSTART;VALUE=DATE-TIME:20201110T160000Z
DTEND;VALUE=DATE-TIME:20201110T180000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/12
DESCRIPTION:Title: Dissecting the ensemble in JT gravity\nby Andreas Blommaert as
part of CERN String Seminars\n\n\nAbstract\nWe discuss the role of wormhol
es and branes in reconciling geometry with quantum mechanics\, based on re
cent developments in JT gravity\, an analytically solvable model of quantu
m gravity in two dimensions. First\, we will see how wormholes enable geom
etry to accurate capture averaged correlators of chaotic quantum systems.
Because these are averaged properties\, naively wormholes in gravitational
theories imply some ensemble interpretation of those theories. However\,
we will see that the geometrical description of individual quantum systems
involves not just wormholes\, but also some background branes. These bran
es encode the microstructure of some given quantum system in bulk geometry
and collapse the ensemble.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kazumi Okuyama
DTSTART;VALUE=DATE-TIME:20201117T100000Z
DTEND;VALUE=DATE-TIME:20201117T120000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/13
DESCRIPTION:Title: JT gravity and KdV equations\nby Kazumi Okuyama as part of CERN
String Seminars\n\n\nAbstract\nWe study the thermal partition function of
Jackiw-Teitelboim (JT)\ngravity using the matrix model description recent
ly found by Saad\,\nShenker and Stanford. We show that the partition funct
ion of JT\ngravity is written as the expectation value of a macroscopic lo
op\noperator in the old matrix model of 2d gravity in the background where
\ninfinitely many couplings are turned on in a specific way. Based on\nthi
s expression we develop a very efficient method of computing the\npartitio
n function in the genus expansion as well as in the low\ntemperature expan
sion by making use of the Korteweg-de Vries\nconstraints obeyed by the par
tition function. \nWe also generalize our analysis to the case of multi-b
oundary\ncorrelators with the help of the boundary creation operator. We\
nformulate a method of computing it up to any order and also find a\nunive
rsal form of the two-boundary correlator in terms of the error\nfunction.
Using this result we are able to write down the analytic\nform of the spec
tral form factor in JT gravity and show how the ramp\nand plateau behavior
arises.\nThis talk is based on the work with Kazuhiro Sakai (arXiv:1911.0
1659\,arXiv:2004.07555)\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Levine
DTSTART;VALUE=DATE-TIME:20201124T130000Z
DTEND;VALUE=DATE-TIME:20201124T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/14
DESCRIPTION:Title: Seeing the Outermost Entanglement Wedge\nby Adam Levine as part
of CERN String Seminars\n\n\nAbstract\nWe study the problem of revealing
the entanglement wedge using simple operations. We ask what operation a se
miclassical observer can do to bring the entanglement wedge into causal co
ntact with the boundary\, via backreaction. In a generic perturbative clas
s of states\, we propose a unitary operation in the causal wedge whose bac
kreaction brings all of the previously causally inaccessible `peninsula' i
nto causal contact with the boundary. This class of cases includes entangl
ement wedges associated to boundary sub-regions that are unions of disjoin
t spherical caps\, and the protocol works to first order in the size of th
e peninsula. The unitary is closely related to the so-called Connes Cocycl
e flow\, which is a unitary that is both well-defined in QFT and localised
to a sub-region. Our construction requires a generalization of the work b
y Ceyhan & Faulkner to regions which are unions of disconnected spherical
caps. We argue that this cocycle should be thought of as naturally general
izing the non-local coupling introduced in the work of Gao\, Jafferis & Wa
ll. If time permits we will discuss forthcoming work which attempts at stu
dying the quantum extremal surface position for bulk theories duel to a su
b-maximally chaotic boundary theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lara Anderson
DTSTART;VALUE=DATE-TIME:20201201T130000Z
DTEND;VALUE=DATE-TIME:20201201T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/15
DESCRIPTION:Title: Topological Textures in Heterotic Theories\nby Lara Anderson as
part of CERN String Seminars\n\n\nAbstract\nIn this talk I will review th
e ways that compactifications of the heterotic string can be subject to co
nstraints on the matter couplings of the 4-dimensional effective theory th
at do not arise from gauge symmetries. Such "topological vanishings" have
the potential to be useful for the realization of certain mass hierarchies
(such as in the famous "mu problem") or dangerously restrictive on the ph
ysical theories. I will describe and compare several different ways that t
opological vanishings arise in heterotic theories and new results that ind
icate they may be a generic feature of such compactifications.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alfred Shapere
DTSTART;VALUE=DATE-TIME:20201208T150000Z
DTEND;VALUE=DATE-TIME:20201208T170000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/16
DESCRIPTION:Title: Quantum Error-Correcting Codes and Narain CFTs\nby Alfred Shape
re as part of CERN String Seminars\n\n\nAbstract\nThere is a rich web of c
onnections between classical error-correcting codes\, Euclidean lattices\,
and chiral conformal field theories. I will explain an analogous relation
ship between quantum error-correcting codes\, Lorentzian lattices\, and no
nchiral CFTs arising from toroidal compactifications of strings. Specifica
lly\, I will show how quantum stabilizer codes are embedded in the operato
r algebras of associated Narain CFTs. With respect to “code” CFTs\, th
e constraints of modular invariance reduce to simple algebraic equations.
Solving these equations provides many examples of physically distinct CFTs
with the same spectrum\; we also find many solutions that do not correspo
nd to any code CFT\, and likely do not correspond to any CFT at all. This
exposes a crucial limitation of the conformal bootstrap program – that i
n general\, a solution of the bootstrap equations implies neither the exis
tence nor the uniqueness of a corresponding CFT.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Natalie Paquette
DTSTART;VALUE=DATE-TIME:20201215T150000Z
DTEND;VALUE=DATE-TIME:20201215T170000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/17
DESCRIPTION:Title: Twisted holography & Koszul duality\nby Natalie Paquette as par
t of CERN String Seminars\n\n\nAbstract\nIn this talk we discuss the probl
em of coupling quantum field theories to topological line defects and expl
ain that it is governed by a central mathematical notion called Koszul dua
lity for associative algebras. We then propose an analogous physical defin
ition of Koszul duality for chiral algebras. We will explain that in the c
ontext of (a twisted version of) AdS(3)/CFT(2)\, in which a chiral algebra
naturally arises in the CFT(2)\, a deformation of this version of Koszul
duality can be used to compute algebra OPEs. This talk is based on work in
collaboration with K. Costello.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabrizio del Monte
DTSTART;VALUE=DATE-TIME:20210112T130000Z
DTEND;VALUE=DATE-TIME:20210112T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/18
DESCRIPTION:Title: BPS quivers of five-dimensional SCFTs\, Topological Strings and q-P
ainlevé equations\nby Fabrizio del Monte as part of CERN String Semin
ars\n\n\nAbstract\nFive-dimensional SCFTs arise from M-theory compactified
on local (toric) Calabi-Yau threefolds. These theories are intrinsically
non-lagrangian\, although they often exhibit a low-energy gauge theory pha
se\, and their BPS states can be constructed as branes wrapping topologica
lly nontrivial cycles in the Calabi-Yau geometry. In this talk I will show
how to extract detailed information about the BPS sector of these theorie
s by the introduction of an associated graph\, called a quiver. The quiver
defines a discrete integrable system\, whose discrete time evolution allo
ws on the one hand to study the BPS particle spectrum of the theory\, on t
he other hand to derive difference equations satisfied by its partition fu
nction.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kantaro Ohmori
DTSTART;VALUE=DATE-TIME:20210119T140000Z
DTEND;VALUE=DATE-TIME:20210119T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/19
DESCRIPTION:Title: Categorical Symmetry in 1+1 dimensions\nby Kantaro Ohmori as pa
rt of CERN String Seminars\n\n\nAbstract\nGlobal symmetry plays a crucial
role in the study of QFT. Recently\, various generalizations of the concep
t of global symmetry has been proposed. In the talks I would like to discu
ss the notion called “categorical symmetry”\, or various other names\,
particularly in 1+1 dimensions. Such a “symmetry” lacks its inverse\,
and described by the mathematical concept of a fusion category\, instead
of a group. Physically it refers to the collection of all the topological
line defects exists in the 2d QFT. A “categorical symmetry” is preserv
ed along an RG flow\, as an ordinary symmetry and its ’t Hooft anomaly d
oes\, which is crucial in its applications. It sometimes admits the notion
of “gauging”\, too.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Horacio Casini
DTSTART;VALUE=DATE-TIME:20210126T130000Z
DTEND;VALUE=DATE-TIME:20210126T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/20
DESCRIPTION:Title: Entropic order parameters for symmetries in QFT\nby Horacio Cas
ini as part of CERN String Seminars\n\n\nAbstract\nIn QFT there is an alge
bra of operators attached to any spacetime region. Simple degradations of
the most harmonious possible relation between algebras and regions are sho
wn to encode generalized symmetries. Nets of algebras with these symmetrie
s allow for a non uniqueness of the algebras that can be assigned to a giv
en region. This non uniqueness suggests a simple geometrical order paramet
er in terms of a relative entropy. These satisfy a ''certainty relation''
connecting the statistics of the order and disorder parameters for complem
entary regions. We describe how the lore about phases of theories with gen
eralized symmetries is seen in this new picture.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Ilesiu
DTSTART;VALUE=DATE-TIME:20210216T150000Z
DTEND;VALUE=DATE-TIME:20210216T170000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/21
DESCRIPTION:Title: The statistical mechanics of near-extremal and near-BPS black holes
\nby Luca Ilesiu as part of CERN String Seminars\n\n\nAbstract\nAn imp
ortant open question in black hole thermodynamics is about the existence o
f a "mass gap" between an extremal black hole and the lightest near-extrem
al state within a sector of fixed charge. In this talk\, I will discuss ho
w to reliably compute the partition function of 4d Reissner-Nordstrom near
-extremal black holes at temperature scales comparable to the conjectured
gap. I will show that the density of states at fixed charge does not exhib
it a gap in the simplest gravitational non-supersymmetric theories\; rathe
r\, at the expected gap energy scale\, we see a continuum of states whose
meaning we will extensively discuss. Finally\, I will present a similar co
mputation for nearly-BPS black holes in 4d N=2 supergravity. As opposed to
their non-supersymmetric counterparts\, such black holes do in fact exhib
it a gap consistent with various string theory predictions.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony
DTSTART;VALUE=DATE-TIME:20210223T130000Z
DTEND;VALUE=DATE-TIME:20210223T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/22
DESCRIPTION:Title: A derivation of AdS/CFT for vector models\nby Ofer Aharony as p
art of CERN String Seminars\n\n\nAbstract\nAfter discussing what it means
to derive the AdS/CFT correspondence\, I will describe our attempts (in co
llaboration with Shai Chester and Erez Urbach\, 2011.06328) to make this c
orrespondence explicit in the simplest case of the U(N) vector model. We e
xplicitly rewrite the path integral for the free or critical U(N) (or O(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\, Jevicki\, Suzuki and Yoo
n and earlier work\, we first rewrite the vector models in terms of bi-loc
al fields\, then expand these fields in eigenmodes of the conformal group\
, and finally map these eigenmodes to those of fields on anti-de Sitter sp
ace. Our results provide an explicit (non-local) action for a high-spin th
eory on anti-de Sitter space\, which is presumably equivalent in the large
N limit to Vasiliev's classical high-spin gravity theory (with some speci
fic gauge-fixing to a fixed background)\, but which can be used also for l
oop computations. Our mapping is explicit within the 1/N expansion\, but i
n principle can be extended also to finite N theories\, where extra constr
aints on products of bulk fields need to be taken into account.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Toldo
DTSTART;VALUE=DATE-TIME:20210302T130000Z
DTEND;VALUE=DATE-TIME:20210302T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/23
DESCRIPTION:Title: Rotating black holes in Anti-de Sitter and updates on the search fo
r multicenter AdS4 black holes\nby Chiara Toldo as part of CERN String
Seminars\n\n\nAbstract\nIn this talk I will review recent progress on the
microstate counting for black holes in Anti-de Sitter spacetime. I will f
ocus mainly on the gravitational part. After reviewing the known solutions
\, I will describe how to construct two classes of stationary BPS configur
ations in theories of four-dimensional supergravity with uplift to M-theor
y. In the second part of my talk I will discuss work in progress that inve
stigates the existence of stable and metastable black hole bound states at
finite chemical potentials in global AdS spacetime\, in the probe approxi
mation. Time permitting\, I will finally discuss the relevance of these se
tups for describing glassy systems via holography.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Guerrieri
DTSTART;VALUE=DATE-TIME:20210309T130000Z
DTEND;VALUE=DATE-TIME:20210309T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/24
DESCRIPTION:Title: Where is String Theory?\nby Andrea Guerrieri as part of CERN St
ring Seminars\n\n\nAbstract\nIn the last few years the S-matrix Bootstrap
provided precise quantitative bounds on the low energy Wilson coefficients
compatible with causality\, crossing symmetry and unitarity for some clas
s of EFTs describing low energy QCD dynamics. In this talk I will discuss
the first application of this formalism to quantum gravity theories. I wil
l focus on the first non universal correction to the flat space scattering
amplitude of 10 dimensional supergravity particles\, and compare the resu
lts with the String Theory predictions.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aninda Sinha
DTSTART;VALUE=DATE-TIME:20210316T130000Z
DTEND;VALUE=DATE-TIME:20210316T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/25
DESCRIPTION:Title: Quantum field theory and the Bieberbach conjecture\nby Aninda S
inha as part of CERN String Seminars\n\n\nAbstract\nI will discuss an intr
iguing correspondence between ingredients in geometric function theory rel
ated to the famous Bieberbach conjecture (de Branges' theorem) and the non
-perturbative crossing symmetric representation of 2-2 scattering amplitud
es of identical scalars. I will point out two sided bounds on the amplitud
e as well as on certain Wilson coefficients that arise from this correspon
dence.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yifan Wang
DTSTART;VALUE=DATE-TIME:20210323T143000Z
DTEND;VALUE=DATE-TIME:20210323T163000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/26
DESCRIPTION:Title: Defects and Anomalies in Quantum Field Theories\nby Yifan Wang
as part of CERN String Seminars\n\n\nAbstract\nI will review some recent d
evelopments in understanding the structure of anomalies in the presence of
defects in CFTs. The defect insertions lead to new 't Hooft anomalies and
conformal anomalies on the defect worldvolume. The latter give rise to de
fect analogs of the c-theorem (a-theorem) which establish the monotonicity
of defect RG flows. With supersymmetry\, the defect conformal anomalies a
re related to the 't Hooft anomalies for certain U(1) R-symmetry in a simp
le way\, and can be determined non-perturbatively from an algebraic proced
ure. In the talk I'll mostly focus on surface defects to be concrete and c
omment on extensions and future directions towards the end.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sakura Schafer-Nameki
DTSTART;VALUE=DATE-TIME:20210330T120000Z
DTEND;VALUE=DATE-TIME:20210330T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/27
DESCRIPTION:Title: Higher Form symmetries in String Theory and Applications to Confine
ment\nby Sakura Schafer-Nameki as part of CERN String Seminars\n\n\nAb
stract\nI will give an overview of recent developments in higher form symm
etries in string theory\, in particular in geometric constructions of QFTs
. As an application I will discuss setups in string theory realizing confi
ning vacua in the light of their 1-form symmetries.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Subham Dutta Chowdhury
DTSTART;VALUE=DATE-TIME:20210406T120000Z
DTEND;VALUE=DATE-TIME:20210406T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/28
DESCRIPTION:Title: Bounds on Regge growth of flat space scattering from bounds on chao
s\nby Subham Dutta Chowdhury as part of CERN String Seminars\n\n\nAbst
ract\nWe study four-point functions of scalars\, conserved currents\, and
stress tensors in a conformal field theory\, generated by a local contact
term in the bulk dual description\, in two different causal configurations
. The first of these is the standard Regge configuration in which the chao
s bound applies. The second is the `causally scattering configuration' in
which the correlator develops a bulk point singularity. We find an express
ion for the coefficient of the bulk point singularity in terms of the bulk
S matrix of the bulk dual metric\, gauge fields and scalars\, and use it
to determine the Regge scaling of the correlator on the causally scatterin
g sheet in terms of the Regge growth of this S matrix. We then demonstrate
that the Regge scaling on this sheet is governed by the same power as in
the standard Regge configuration\, and so is constrained by the chaos boun
d\, which turns out to be violated unless the bulk flat space S matrix gro
ws no faster than s^2 in the Regge limit. It follows that in the context o
f the AdS/CFT correspondence\, the chaos bound applied to the boundary fie
ld theory implies that the S matrices of the dual bulk scalars\, gauge fie
lds\, and gravitons obey the Classical Regge Growth (CRG) conjecture.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dalimil Mazac
DTSTART;VALUE=DATE-TIME:20210413T130000Z
DTEND;VALUE=DATE-TIME:20210413T150000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/29
DESCRIPTION:Title: Sharp Boundaries for the Swampland\nby Dalimil Mazac as part of
CERN String Seminars\n\n\nAbstract\nI will discuss the problem of boundin
g higher derivative couplings in consistent weakly coupled gravitational t
heories. The starting point will be general assumptions about analyticity
and Regge growth of the S-matrix. Higher derivative couplings are expected
to be of order one in the units of the UV cutoff. Our approach justifies
this expectation and allows us to prove precise bounds on the order one co
efficients. I will explain that the notorious difficulties presented by th
e graviton pole can be overcome by measuring couplings at small impact par
ameter\, rather than in the forward limit. I will illustrate the method in
theories containing a massless scalar coupled to gravity\, and in theorie
s with maximal supersymmetry.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ben Freivogel
DTSTART;VALUE=DATE-TIME:20210420T120000Z
DTEND;VALUE=DATE-TIME:20210420T140000Z
DTSTAMP;VALUE=DATE-TIME:20210419T095636Z
UID:CERNStringSem/30
DESCRIPTION:Title: Wormholes from averaging over states\nby Ben Freivogel as part
of CERN String Seminars\n\nInteractive livestream: https://indico.cern.ch/
event/1019761/\n\nAbstract\nI will show that wormholes naturally arise as
the gravity dual of an average over different states within a single confo
rmal field theory. These wormholes give a simple way to diagnose how typic
al pure states differ from the thermal density matrix. Based on work to a
ppear with D. Nikolakopoulou and A. Rotundo.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/30/
URL:https://indico.cern.ch/event/1019761/
END:VEVENT
END:VCALENDAR