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BEGIN:VEVENT
SUMMARY:Sameer Murthy (Kings College London)
DTSTART:20200526T120000Z
DTEND:20200526T130000Z
DTSTAMP:20260422T212528Z
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:20200616T120000Z
DTEND:20200616T130000Z
DTSTAMP:20260422T212528Z
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:20200623T140000Z
DTEND:20200623T150000Z
DTSTAMP:20260422T212528Z
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:20200707T130000Z
DTEND:20200707T140000Z
DTSTAMP:20260422T212528Z
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:20200811T120000Z
DTEND:20200811T130000Z
DTSTAMP:20260422T212528Z
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:20200922T140000Z
DTEND:20200922T160000Z
DTSTAMP:20260422T212528Z
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:20200929T120000Z
DTEND:20200929T140000Z
DTSTAMP:20260422T212528Z
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:20201006T120000Z
DTEND:20201006T140000Z
DTSTAMP:20260422T212528Z
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:20201020T140000Z
DTEND:20201020T160000Z
DTSTAMP:20260422T212528Z
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:20201013T130000Z
DTEND:20201013T140000Z
DTSTAMP:20260422T212528Z
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:20201027T130000Z
DTEND:20201027T150000Z
DTSTAMP:20260422T212528Z
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:20201110T160000Z
DTEND:20201110T180000Z
DTSTAMP:20260422T212528Z
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:20201117T100000Z
DTEND:20201117T120000Z
DTSTAMP:20260422T212528Z
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:20201124T130000Z
DTEND:20201124T150000Z
DTSTAMP:20260422T212528Z
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:20201201T130000Z
DTEND:20201201T150000Z
DTSTAMP:20260422T212528Z
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:20201208T150000Z
DTEND:20201208T170000Z
DTSTAMP:20260422T212528Z
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:20201215T150000Z
DTEND:20201215T170000Z
DTSTAMP:20260422T212528Z
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:20210112T130000Z
DTEND:20210112T150000Z
DTSTAMP:20260422T212528Z
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:20210119T140000Z
DTEND:20210119T150000Z
DTSTAMP:20260422T212528Z
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:20210126T130000Z
DTEND:20210126T150000Z
DTSTAMP:20260422T212528Z
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:20210216T150000Z
DTEND:20210216T170000Z
DTSTAMP:20260422T212528Z
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:20210223T130000Z
DTEND:20210223T150000Z
DTSTAMP:20260422T212528Z
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:20210302T130000Z
DTEND:20210302T150000Z
DTSTAMP:20260422T212528Z
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:20210309T130000Z
DTEND:20210309T150000Z
DTSTAMP:20260422T212528Z
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:20210316T130000Z
DTEND:20210316T150000Z
DTSTAMP:20260422T212528Z
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:20210323T143000Z
DTEND:20210323T163000Z
DTSTAMP:20260422T212528Z
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:20210330T120000Z
DTEND:20210330T140000Z
DTSTAMP:20260422T212528Z
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:20210406T120000Z
DTEND:20210406T140000Z
DTSTAMP:20260422T212528Z
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:20210413T130000Z
DTEND:20210413T150000Z
DTSTAMP:20260422T212528Z
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:20210420T120000Z
DTEND:20210420T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/30
DESCRIPTION:Title: Wormholes from averaging over states\nby Ben Freivogel as part
of CERN String Seminars\n\n\nAbstract\nI will show that wormholes naturall
y arise as the gravity dual of an average over different states within a s
ingle conformal field theory. These wormholes give a simple way to diagnos
e how typical pure states differ from the thermal density matrix. Based o
n work to appear with D. Nikolakopoulou and A. Rotundo.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio Parra Martinez
DTSTART:20210427T140000Z
DTEND:20210427T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/31
DESCRIPTION:Title: Collider tools for classical gravity\nby Julio Parra Martinez a
s part of CERN String Seminars\n\n\nAbstract\nI will describe recent progr
ess in the program to apply tools originally developed for computing cross
sections in colliders to problems in classical general relativity. This e
ffort has recently produced state-of-the-art computations of quantities re
levant for current and future gravitational wave detectors\, such as the c
onservative two-body Hamiltonian at the fourth order in Newton’s constan
t\, G^4\, as well as the G^3 radiated energy in binary black hole encounte
rs and elliptical orbits. I will explain how these calculations were made
possible by leveraging on-shell techniques\, effective field theory\, mode
rn loop integration machinery and an improved understanding of the connect
ion between classical scattering amplitudes and the semiclassical on-shell
action.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Pate
DTSTART:20210504T130000Z
DTEND:20210504T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/32
DESCRIPTION:Title: Flatspace Holography: Celestial Amplitudes and Symmetries\nby M
onica Pate as part of CERN String Seminars\n\n\nAbstract\nThe identificati
on of quantum field theoretic soft theorems with constraints from infinite
-dimensional asymptotic symmetries offers exciting prospects for the devel
opment of flatspace holography. In four spacetime dimensions\, the asympto
tic symmetry group includes the local conformal (Virasoro) symmetry of two
dimensions\, motivating the proposal that 4D scattering is holographicall
y dual to a 2D conformal theory. Lorentz symmetry in four dimensions compr
ises the global part of the 2D conformal group of the dual. Celestial a
mplitudes which capture the scattering of particles in boost as opposed to
momentum eigenstates transform like correlation functions of primary oper
ators under 4D Lorentz transformations. I will describe how celestial am
plitudes admit a variety of other properties -- including an operator prod
uct expansion and rich symmetry algebra -- which are indicative of an unde
rlying two-dimensional holographic dual theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steve Shenker
DTSTART:20210511T150000Z
DTEND:20210511T170000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/33
DESCRIPTION:Title: Wormholes without averaging\nby Steve Shenker as part of CERN S
tring Seminars\n\n\nAbstract\nAfter averaging over fermion couplings\, SYK
has a collective field description that sometimes has “wormhole” solu
tions. We study the fate of these wormholes when the couplings are fixed.
Working mainly in a simple model\, we find that the wormhole saddles persi
st\, but that new saddles also appear elsewhere in the integration space
– “half-wormholes.” The wormhole contributions depend only weakly on
the specific choice of couplings\, while the half-wormhole contributions
are strongly sensitive. The half-wormholes are crucial for factorization o
f decoupled systems with fixed couplings\, but they vanish after averaging
\, leaving the non-factorizing wormhole behind. (Joint work with Phil S
aad\, Douglas Stanford and Shunyu Yao.)\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello
DTSTART:20210518T140000Z
DTEND:20210518T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/34
DESCRIPTION:Title: Four-dimensional integrability and twistors\nby Kevin Costello
as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Kolchmeyer
DTSTART:20210525T120000Z
DTEND:20210525T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/35
DESCRIPTION:Title: Dynamical End-of-the-world Branes in Jackiw-Teitelboim Gravity\
nby David Kolchmeyer as part of CERN String Seminars\n\n\nAbstract\nJackiw
-Teitelboim gravity with end-of-the-world (EoW) branes has been used to st
udy the black hole information problem. In this talk\, I consider dynamica
l EoW branes by summing over loops of branes in the Euclidean path integra
l. The UV divergences that arise are treated in the context of effective f
ield theory. The EoW branes make a contribution to the black hole entropy
that is consistent with a state-counting interpretation of the entropy. I
will also discuss how the effective field theory logic is mirrored in the
dual matrix model.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Suvrat Raju
DTSTART:20210928T120000Z
DTEND:20210928T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/36
DESCRIPTION:Title: Holography of Information and Massive Islands\nby Suvrat Raju a
s part of CERN String Seminars\n\n\nAbstract\nWe will review recent result
s that suggest that\, in any standard theory of quantum gravity\, informat
ion available on the bulk of a Cauchy slice must also be available near th
e boundary of the slice. These ideas indicate how holography should be
extended to four dimensional asymptotically flat spacetimes but they also
shed light on the origins of AdS/CFT. We contrast this picture with the pa
radigm of islands and argue that islands are consistent only in theories o
f massive gravity.\n\nReferences:\n1) "Holography from the Wheeler-DeWitt
equation"\nhttps://arxiv.org/abs/2107.14802 \n2) "Inconsistency of Islands
in Theories with Long-Range Gravity"\nhttps://arxiv.org/abs/2107.03390 \n
3) "Lessons from the Information Paradox" (review)\nhttps://arxiv.org/abs/
2012.05770\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen
DTSTART:20211005T120000Z
DTEND:20211005T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/37
DESCRIPTION:Title: D-instanton amplitudes in string theory\nby Ashoke Sen as part
of CERN String Seminars\n\n\nAbstract\nI shall review the problems in comp
uting D-instanton\ncontribution to string amplitudes using the usual world
-sheet methods\, and\nrecent progress in overcoming these difficulties usi
ng insights from\nstring field theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dierigl\, Markus
DTSTART:20211012T120000Z
DTEND:20211012T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/38
DESCRIPTION:Title: The anomaly that was not meant IIB\nby Dierigl\, Markus as part
of CERN String Seminars\n\n\nAbstract\nIn this talk I will discuss possib
le quantum anomalies in the duality group of type IIB string theory. Quite
surprisingly\, these do not vanish\, which would signal an inconsistency
of F-theory. A subtle modification of the type IIB Chern-Simons term cance
ls the anomalies in a highly non-trivial way. However\, in principle there
are alternative ways to cancel the anomaly which might point towards the
existence of a discrete string theory landscape.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pietro Ferrero
DTSTART:20211019T120000Z
DTEND:20211019T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/39
DESCRIPTION:Title: Gluon scattering in AdS from CFT\nby Pietro Ferrero as part of
CERN String Seminars\n\n\nAbstract\nI will present a class of recently com
puted holographic correlators between half-BPS operators in a vast array o
f SCFTs with non-maximal superconformal symmetry in dimensions d=3\,4\,5\,
6. Via AdS/CFT\, these four-point functions are dual to gluon scattering a
mplitudes in AdS. Exploiting the notion of MRV limit I will show that\, at
tree level\, all such correlators are completely fixed by symmetries and
consistency conditions. Our results encode a wealth of novel CFT data and
exhibit various emergent structures\, including Parisi-Sourlas supersymmet
ry\, hidden conformal symmetry and color-kinematics duality.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Closset
DTSTART:20211026T120000Z
DTEND:20211026T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/40
DESCRIPTION:Title: The U-plane of rank-one 4d N=2 KK theories\nby Cyril Closset as
part of CERN String Seminars\n\n\nAbstract\nI will revisit the Seiberg-Wi
tten description of the Coulomb branch of rank-one 4d N=2 supersymmetric Q
FTs\, including aspects of the global symmetry\, from the point of view of
rational elliptic surfaces. This will include\, in particular\, a detaile
d study of the 5d superconformal field theories with E_n symmetry\, compac
tified on a circle. I will also sketch how to derive BPS quivers from that
perspective. Interesting modular properties of the SW geometries will pla
y a key role.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Faulkner
DTSTART:20211102T140000Z
DTEND:20211102T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/41
DESCRIPTION:Title: Reflected Entropy for Holography and Beyond\nby Tom Faulkner as
part of CERN String Seminars\n\n\nAbstract\nI will discuss a new quantum
information measure\, called reflected entropy\, that was originally disco
vered in holography. Reflected entropy goes beyond entanglement entropy in
its ability to constrain the patterns of entanglement and in holographic
theories allows one to move beyond probing minimal surfaces in the emergen
t bulk. I will then discuss more recent results on studying this quantity
in random tensor networks where similar dualities are discovered.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clifford Johnson
DTSTART:20211109T130000Z
DTEND:20211109T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/42
DESCRIPTION:Title: The Microstate Physics of JT gravity and Supergravity\nby Cliff
ord Johnson as part of CERN String Seminars\n\n\nAbstract\nMany key physic
al phenomena in JT gravity are only accessible if one goes beyond the topo
logical expansion to capture non-perturbative effects. This can be done ex
plicitly using random matrix models\, if formulated in such a way as to ex
tract non-perturbative physics. Such a framework\, developed previously fo
r JT by the Author\, is briefly reviewed in this talk. Then a new tool is
added: a particular Fredholm determinant. It allows for a surprisingly tho
rough excavation of the detailed microstate spectrum of a non-perturbative
completion of JT gravity and several super JT variants. This then allows
for the full quenched Free Energy to be computed for these models for the
first time\, completing the low temperature thermodynamics. Possible impli
cations for the spectrum of higher dimensional near extremal black holes a
re suggested.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Puhm
DTSTART:20211116T130000Z
DTEND:20211116T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/43
DESCRIPTION:Title: Towards flat space holography via diamonds on the celestial sphere<
/a>\nby Andrea Puhm as part of CERN String Seminars\n\n\nAbstract\nThe bas
ic observable of quantum gravity in asymptotically flat spacetimes is the
S-matrix. When recast in a basis of boost eigenstates scattering amplitude
s transform as conformal correlators of primary operators in the dual ''ce
lestial CFT''. This observation together with novel insights about the inf
rared aspects of gauge theory and gravity have reinvigorated attempts at a
holographic principle for flat space. Essential to building a holographic
dictionary is to understand the spectrum and the symmetries of the dual t
heory. I will describe recent progress in this direction. A natural langua
ge for describing the (conformally) soft sector of scattering is via celes
tial diamonds which encode the structure of global conformal multiplets an
d\, upon adding supersymmetry\, stack into a pyramid. They unify the discu
ssion of QFT soft theorems\, (asymptotic) symmetry generators and Goldston
e modes appearing in conformal dressings. Combining these ingredients I wi
ll end with some speculations on effective descriptions for the conformall
y soft sector of celestial CFT which captures the spontaneous (asymptotic)
symmetry breaking dynamics.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter
DTSTART:20211130T130000Z
DTEND:20211130T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/44
DESCRIPTION:Title: On S-Duality in N=4 SYM and Gravity\nby Eric Perlmutter as part
of CERN String Seminars\n\n\nAbstract\nFour-dimensional N=4 super-Yang-Mi
lls obeys S-duality. A new way to process this symmetry leads to strong co
nsequences for the CFT data and for the nature of holographic duality. Bas
ed on work with Scott Collier.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Nega
DTSTART:20211207T130000Z
DTEND:20211207T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/45
DESCRIPTION:Title: Calabi-Yau Manifolds and Feynman Integrals — The Family of Banana
Graphs\nby Christoph Nega as part of CERN String Seminars\n\n\nAbstra
ct\nIn this talk I will explain the relation between Calabi-Yau manifolds
and their mathematics and Feynman integral computations. We will see how c
oncepts from Calabi-Yau geometries and especially Calabi-Yau motives can b
e used to compute multi-loop Feynman integrals. This will be exemplified w
ith the so called banana graphs. First\, I will give a short introduction
to Feynman integrals and Calabi-Yau manifolds. Then we will see how the ma
thematics of Calabi-Yau manifolds (variations of Hodge structures\, Griffi
ths transversality\, \nΓ-class\, ...) constrain or even determine the cor
responding Feynman integrals\, here the banana graphs. Then I will also sh
ortly explain how the banana integrals can be solved in dimensional regula
rization in the equal- as well as in the generic-mass case. Finally\, I wi
ll make some remarks what we can in general learn from Calabi-Yau spaces i
n the context of Feynman integrals.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Beatrix Muehlmann
DTSTART:20211214T130000Z
DTEND:20211214T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/46
DESCRIPTION:Title: The semiclassical gravitational path integral and random matrices\nby Beatrix Muehlmann as part of CERN String Seminars\n\n\nAbstract\nIn
this talk I will discuss the genus expansion over compact Riemann surface
s of the semiclassical gravitational path integral in two spacetime dimens
ions coupled to one of the minimal models (2\,2m-1). In the semiclassical
limit we take m to infinity. Conjecturally this path integral allows for a
completion in terms of an integral over large random Hermitian matrices\,
known as a multicritical matrix integral. I will discuss the genus expans
ion of multicritical matrix integrals and relate invariant quantities stem
ming both from matrix as well as gravity calculations. Inspired by the pro
posal of Gibbons and Hawking relating the de Sitter entropy to a gravitati
onal path integral\, this setup paves a possible path toward a microscopic
picture of a two-dimensional de Sitter universe.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Hartman
DTSTART:20211221T130000Z
DTEND:20211221T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/47
DESCRIPTION:Title: Talk by Tom Hartman\nby Tom Hartman as part of CERN String Semi
nars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jens Eisert
DTSTART:20220111T130000Z
DTEND:20220111T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/48
DESCRIPTION:Title: Linear growth of quantum circuit complexity\nby Jens Eisert as
part of CERN String Seminars\n\n\nAbstract\nQuantifying quantum states' co
mplexity is a key problem in various subfields of science\, from quantum c
omputing to black-hole physics. In this talk\, we prove a prominent conjec
ture by Brown and Susskind about how random quantum circuits' complexity i
ncreases [1]. Consider constructing a unitary from Haar-random two-qubit q
uantum gates. Implementing the unitary exactly requires a circuit of some
minimal number of gates - the unitary's exact circuit complexity. We prove
that this complexity grows linearly in the number of random gates\, with
unit probability\, until saturating after exponentially many random gates.
Our proof is surprisingly short\, given the established difficulty of low
er-bounding the exact circuit complexity. Our strategy combines differenti
al topology and elementary algebraic geometry with an inductive constructi
on of Clifford circuits. We have a brief look at the role entanglement pla
ys here [2]. In a long outlook\, we will have a look at what could be call
ed a resource theory of quantum uncomplexity [3].\n\n[1] J. Haferkamp\, P.
Faist\, N. B. T. Kothakonda\, J. Eisert\, N. Yunger Halpern\, Linear grow
th of quantum circuit complexity\, arXiv:2106.05305\, Nature Physics\, in
press (2022).\n[2] J. Eisert\, Entangling power and quantum circuit comple
xity\, arXiv:2104.03332\, Physical Review Letters 127\, 020501 (2021).\n[3
] N. Yunger Halpern\, N. B. T. Kothakonda\, J. Haferkamp\, A. Munson\, J.
Eisert\, P. Faist\, Resource theory of quantum uncomplexity\, arXiv:2110.1
1371 (2021).\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Nardoni
DTSTART:20220118T100000Z
DTEND:20220118T120000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/49
DESCRIPTION:Title: From Seiberg-Witten Theory to Adjoint QCD\nby Emily Nardoni as
part of CERN String Seminars\n\n\nAbstract\nStandard lore suggests that fo
ur-dimensional SU(N) gauge theory with 2 massless adjoint Weyl fermions ("
adjoint QCD") flows to a phase with confinement and chiral symmetry breaki
ng. In this talk\, we will test and present new evidence for this lore. Ou
r strategy involves realizing adjoint QCD in the deep IR of a renormalizat
ion group flow descending from SU(N) Seiberg-Witten theory\, deformed by a
soft supersymmetry-breaking mass for its adjoint scalars. A crucial role
in the analysis is played by a dual Lagrangian that originates from the mu
lti-monopole points of Seiberg-Witten theory\, and which can be used to ex
plore the phase diagram as a function of the supersymmetry-breaking mass.
The semi-classical phases of this dual Lagrangian suggest that the softly
broken SU(N) theory traverses a sequence of phases\, separated by first-or
der transitions\, that interpolate between the Coulomb phase of Seiberg-Wi
tten theory and the confining\, chiral symmetry breaking phase expected fo
r adjoint QCD.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Javier Magan
DTSTART:20220125T130000Z
DTEND:20220125T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/50
DESCRIPTION:Title: A new look at completeness and generalized symmetries\nby Javie
r Magan as part of CERN String Seminars\n\n\nAbstract\nWe describe a gener
al principle of completeness in QFT. It asserts that the physical observab
le algebras produced by local degrees of freedom are the maximal ones comp
atible with causality. We elaborate on equivalent statements to this princ
iple such as the non-existence of generalized symmetries and the uniquenes
s of the net of algebras. For non-complete theories\, we explain how the e
xistence of generalized symmetries is unavoidable\, and further\, that the
y always come in dual pairs with precisely the same "size"\, measured by t
he Jones or algebraic index. Entropic order/disorder parameters can be def
ined that sense the dual pairs of generalized symmetries and satisfy a rel
ation dubbed the certainty principle\, due to its connection with the unce
rtainty principle in quantum mechanics. Using this new understanding we pr
ove a recent conjecture by Harlow and Ooguri concerning a universal formul
a for the charged density of states in QFT\, comment on relations with the
Weinberg-Witten theorem\, and argue against the existence of generalized
symmetries in the bulk of holographic theories.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin Kaidi
DTSTART:20220201T150000Z
DTEND:20220201T170000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/51
DESCRIPTION:Title: Kramers-Wannier-like duality defects in (3+1)d gauge theories\n
by Justin Kaidi as part of CERN String Seminars\n\n\nAbstract\nI will intr
oduce a class of non-invertible topological defects in (3+1)d gauge theori
es whose fusion rules are the higher-dimensional analogs of those of the K
ramers-Wannier defect in the (1+1)d critical Ising model. As in the lower-
dimensional case\, the presence of such non-invertible defects implies sel
f-duality under a particular gauging of the discrete (higher-form) symmetr
ies. I will illustrate this by means of the example of SO(3) Yang-Mills (Y
M) at θ=π\, as well as SU(2)N=4 SYM at τ=i.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Sharpe
DTSTART:20220208T130000Z
DTEND:20220208T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/52
DESCRIPTION:Title: An introduction to decomposition\nby Eric Sharpe as part of CER
N String Seminars\n\n\nAbstract\nIn this talk I will review work on 'decom
position\,' a property of 2d theories with 1-form symmetries and\, more ge
nerally\, d-dim'l theories with (d-1)-form symmetries. Decomposition is th
e observation that such quantum field theories are equivalent to ('decompo
se into’) disjoint unions of other QFTs\, known in this context as "univ
erses.”\n\nExamples include two-dimensional gauge theories and orbifolds
with matter invariant under a subgroup of the gauge group. Decomposition
explains and relates several physical properties of these theories -- for
example\, restrictions on allowed instantons arise as a "multiverse interf
erence effect" between contributions from constituent universes.\n\nFirst
worked out in 2006 as part of efforts to understand string propagation on
stacks\, decomposition has been the driver of a number of developments sin
ce. In the first half of this talk\, I will review decomposition\; in the
second half\, I will focus on the recent application to anomaly resolution
of Wang-Wen-Witten in two-dimensional orbifolds.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou
DTSTART:20220215T160000Z
DTEND:20220215T173000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/53
DESCRIPTION:Title: Falling inside holographic black holes\nby Lampros Lamprou as p
art of CERN String Seminars\n\n\nAbstract\nI will present a bulk reconstru
ction technique in AdS/CFT suitable for addressing a facet of the black ho
le information problem: how to unambiguously predict the results of measur
ements accessible to an infalling observer in the black hole interior. I w
ill explicitly apply the method in the AdS_2/SYK correspondence and commen
t on its generalizations.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elli Pomoni
DTSTART:20220222T130000Z
DTEND:20220222T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/54
DESCRIPTION:Title: Dynamical spin chains in 4D N = 2 SCFTs\nby Elli Pomoni as part
of CERN String Seminars\n\n\nAbstract\nIn this talk we will revisit the s
tudy of spin chains capturing the spectral problem of 4d N = 2 SCFTs in th
e planar limit. At one loop and in the quantum plane limit\, we will disco
ver a quasi-Hopf symmetry algebra\, defined by the R-matrix read off from
the superpotential. This implies that when orbifolding the N = 4 symmetry
algebra down to the N = 2 one and then marginaly deforming\, the broken ge
nerators are not lost\, but get upgraded to quantum generators. Thereafter
\, we will demonstrate that these chains are dynamical\, in the sense that
their Hamiltonian depends on a parameter which is dynamically determined
along the chain. At one loop we will show how to map the holomorphic SU(3)
scalar sector to a dynamical 15-vertex model\, which corresponds to an RS
OS model\, whose adjacency graph can be read off from the gauge theory qui
ver/brane tiling. One scalar SU(2) sub-sector is described by an alternati
ng nearest-neighbour Hamiltonian\, while another choice of SU(2) sub-secto
r leads to a dynamical dilute Temperley-Lieb model. These sectors have a c
ommon vacuum state\, around which the magnon dispersion relations are natu
rally uniformised by elliptic functions. For the example of the SU(N)xSU(N
) quiver theory we will study these dynamical chains by solving the one- a
nd two-magnon problems with the coordinate Bethe ansatz approach.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shamit Kachru
DTSTART:20220301T163000Z
DTEND:20220301T183000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/55
DESCRIPTION:Title: Fractons and D-branes\nby Shamit Kachru as part of CERN String
Seminars\n\n\nAbstract\nI discuss field theories of fractons\, with a focu
s on the role of foliated field theories and field theories with exotic sy
mmetry in their construction. I then turn to the realization\n— on syste
ms of branes in string theory\n— of several novel theories of this sort.
\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scott Collier
DTSTART:20220308T150000Z
DTEND:20220308T170000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/56
DESCRIPTION:Title: Bootstrapping boundaries and branes\nby Scott Collier as part o
f CERN String Seminars\n\n\nAbstract\nI will describe recent work with Dal
imil Mazac and Yifan Wang initiating the systematic bootstrap study of con
formal boundary conditions in 2d CFTs by investigation of the bootstrap eq
uation that arises from the open-closed consistency condition of the annul
us partition function with identical boundaries. We find that this deceivi
ngly simple bootstrap equation\, when combined with unitarity\, leads to s
urprisingly strong constraints on admissible boundary states. In particula
r\, we derive universal bounds on the tension (boundary entropy) of stable
boundary conditions\, which provide a rigorous diagnostic for potential D
-brane decays. We also find unique solutions to the bootstrap problem of s
table branes in a number of rational CFTs. Along the way\, we observe a cu
rious connection between the annulus bootstrap and the sphere packing prob
lem\, which is a natural extension of previous work on the modular bootstr
ap. We also derive bounds on the boundary entropy at large central charge.
These potentially have implications for end-of-the-world branes in pure g
ravity on AdS_3.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Heckman
DTSTART:20220315T130000Z
DTEND:20220315T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/57
DESCRIPTION:Title: Top Down Approach to Ensemble Averaging\nby Jonathan Heckman as
part of CERN String Seminars\n\n\nAbstract\nEnsemble averaging in quantum
field theory is a well-defined procedure which is also of much recent int
erest in the context of the AdS/CFT correspondence. In this talk we presen
t a stringy realization of quantum field theory ensembles in D ≤ 4 space
time dimensions. This provides a UV completion of a recent proposal of Mar
olf and Maxfield that there is a high-dimensional Hilbert space for baby u
niverses\, but one that is compatible with the proposed Swampland constrai
nts of McNamara and Vafa. We identify two ways in which our construction b
reaks down\, one of which is sensitive to short distance effects\, and one
which is an entropic effect for objects with a large number of microstate
s. The construction thus provides an explicit set of counterexamples to th
e claim that holography can be fully decoupled from top down consideration
s.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Caputa
DTSTART:20220322T130000Z
DTEND:20220322T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/58
DESCRIPTION:Title: Krylov complexity for operators and states\nby Paweł Caputa as
part of CERN String Seminars\n\n\nAbstract\nI will discuss a recent notio
n of complexity in quantum systems called Krylov complexity. After definin
g it for operators as well as for states\, I will present some results whi
ch test this interesting new probe in different many-body systems. This ta
lk will be based on arXiv: 2109.03824\, 2110.10519 and 2202.06957.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomasevic
DTSTART:20220329T120000Z
DTEND:20220329T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/59
DESCRIPTION:Title: Black tsunamis and naked singularities in AdS\nby Marija Tomase
vic as part of CERN String Seminars\n\n\nAbstract\nWe study the evolution
of the Gregory-Laflamme instability for black strings in global AdS spacet
ime\, and investigate the CFT dual of the formation of a bulk naked singul
arity. Using an effective theory in the large D limit\, we uncover a rich
variety of dynamical behaviour\, depending on the thickness of the string
and on initial perturbations. These include: large inflows of horizon gene
rators from the asymptotic boundary (a `black tsunami')\; a pinch-off of t
he horizon that likely reveals a naked singularity\; and competition betwe
en these two behaviours\, such as a nakedly singular pinch-off that subseq
uently gets covered by a black tsunami. The holographic dual describes dif
ferent patterns of heat flow due to the Hawking radiation of two black hol
es placed at the antipodes of a spherical universe. We also present a mode
l that describes\, in any D\, the burst in the holographic stress-energy t
ensor when the signal from a bulk self-similar naked singularity reaches t
he boundary. The model shows that the shear components of the boundary str
ess diverge in finite time\, while the energy density and pressures from t
he burst vanish.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gustavo Joaquin Turiaci
DTSTART:20220405T140000Z
DTEND:20220405T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/60
DESCRIPTION:Title: Nearly BPS black holes and the spectrum of N=4 Yang Mills\nby G
ustavo Joaquin Turiaci as part of CERN String Seminars\n\n\nAbstract\nWe w
ill discuss quantum corrections in the gravitational path integral around
nearly 1/16-BPS black holes in asymptotically AdS5 x S5 space\, dual to he
avy operators in N=4 SYM. These quantum corrections come from a version of
the N=2 super-Schwarzian theory which captures the breaking of the SU(1\,
1|1) near horizon symmetry at finite temperature and chemical potential. U
sing this approach\, holography predicts the presence of a gap between the
BPS black holes and the lightest near-BPS black holes\, and the spectrum
of near-BPS states that lie above this gap. We will also discuss stringy a
nd non-perturbative corrections that can affect the black hole spectrum.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manus Visser
DTSTART:20220412T120000Z
DTEND:20220412T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/61
DESCRIPTION:Title: De Sitter Entropy and the Gravitational Path Integral\nby Manus
Visser as part of CERN String Seminars\n\n\nAbstract\nGibbons and Hawking
famously derived the de Sitter horizon entropy from the Euclidean gravita
tional path integral in the saddle point approximation. In this talk we ex
tend this result in two different ways. First\, we compute the entropy of
de Sitter black holes from the on-shell Euclidean action\, and take their
contributions in the gravitational path integral into account using the fo
rmalism of constrained instantons. We use this to calculate the pair creat
ion rate of arbitrary mass black holes in de Sitter space. Second\, in two
-dimensional de Sitter space we show how the generalized entropy can be ob
tained from an on-shell action for semiclassical dilaton gravity in the mi
crocanonical ensemble. Minimizing the action yields extremizing the genera
lized entropy\, consistent with the island formula.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorrit Kruthoff
DTSTART:20220419T143000Z
DTEND:20220419T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/62
DESCRIPTION:Title: Higher spin JT gravity and a matrix model dual\nby Jorrit Kruth
off as part of CERN String Seminars\n\n\nAbstract\nIn this talk I will pro
pose and discuss a generalization of the Saad-Shenker-Stanford duality bet
ween matrix models and JT gravity to the case in which the bulk includes h
igher spin fields. Using an PSL(N\,R) BF theory we compute the disk and ge
neralization of the trumpet partition function in this theory. Using an ap
propriate subspace of the moduli space of flat PSL(N\,R) connections on a
Riemann surface Σ we propose a recipe for computing the cylinder contribu
tion. This gives a 𝑇𝑁−1 behaviour at late times 𝑇\, signaling a
deviation from conventional random matrix theory. To account for this dev
iation\, we propose that the bulk theory is dual to a matrix model consist
ing of N-1 commuting matrices associated to the N-1 conserved charges in t
he boundary theory. Due to its modified eigenvalue repulsion\, the spectra
l two-point function reproduces the late time gravitational answer.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claire Zukowski
DTSTART:20220503T120000Z
DTEND:20220503T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/63
DESCRIPTION:Title: Virasoro Entanglement Berry Phases\nby Claire Zukowski as part
of CERN String Seminars\n\n\nAbstract\nI will describe the parallel transp
ort of modular Hamiltonians encoding entanglement properties of a state. T
he Berry curvature associated to state-changing parallel transport is the
Kirillov-Kostant symplectic form on an associated coadjoint orbit\, one wh
ich differs appreciably from known Virasoro orbits. I will show that the b
oundary parallel transport process computes a bulk symplectic form for a E
uclidean geometry obtained from the backreaction of a cosmic brane\, with
Dirichlet boundary conditions at the location of the brane. This construct
ion gives a definition for the symplectic form on an entanglement wedge.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dan Roberts
DTSTART:20220510T120000Z
DTEND:20220510T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/64
DESCRIPTION:Title: The Principles of Deep Learning Theory\nby Dan Roberts as part
of CERN String Seminars\n\n\nAbstract\nDeep learning is an exciting approa
ch to modern artificial intelligence based on artificial neural networks.
The goal of this talk is to provide a blueprint — using tools from physi
cs — for theoretically analyzing deep neural networks of practical relev
ance. This task will encompass both understanding the statistics of initia
lized deep networks and determining the training dynamics of such an ensem
ble when learning from data. Borrowing from the "effective theory" framewo
rk of physics and developing a perturbative 1/n expansion around the limit
of infinite hidden-layer width\, we will find a principle of sparsity tha
t will let us describe effectively-deep networks of practical large-but-fi
nite-width networks.\n\nThis talk is based on a book\, "The Principles of
Deep Learning Theory\," co-authored with Sho Yaida and based on research a
lso in collaboration with Boris Hanin. It will be published this month by
Cambridge University Press.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pronobesh Maity
DTSTART:20220517T120000Z
DTEND:20220517T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/65
DESCRIPTION:Title: From Fields to Strings\nby Pronobesh Maity as part of CERN Stri
ng Seminars\n\n\nAbstract\nI will describe a mechanism to reorganize the F
eynman diagrams of a perturbative large N gauge theory into localized inte
grals over closed string moduli space using the Strebel parametrization of
the latter. This will be explicitly illustrated for free symmetric produc
t orbifold CFTs where holomorphic covering maps play a key role. After rec
asting these covering maps in terms of dual worldsheet twistor fields in
𝐴𝑑𝑆3\, it will be generalized for 𝐴𝑑𝑆5. Imposing approp
riate reality conditions\, I will discuss a proposed stringy incidence rel
ation. For correlators of free =4 SYM with special kinematics\, I will
then show an explicit construction of these twistor covering maps\, where
the regularized "Strebel area" of the worldsheet corresponding to these ma
ps\, reproduces the Feynman propagator.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Valentin Benedetti
DTSTART:20220628T120000Z
DTEND:20220628T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/67
DESCRIPTION:Title: Generalized symmetries and Noether's theorem in QFT\nby Valenti
n Benedetti as part of CERN String Seminars\n\n\nAbstract\nWe show that ge
neralized symmetries cannot be charged under a continuous global symmetry
having a Noether current. Further\, only non-compact generalized symmetrie
s can be charged under a continuous global symmetry. These results unravel
topological obstructions to the existence of a Noether current in QFT. We
discuss some examples\, including the free massless graviton. We use thes
e results to rederive Weinberg-Witten’s theorem within local QFT\, gener
alizing it to massless particles in arbitrary dimensions and representatio
ns of the Lorentz group. We end up discussing the conditions for the exist
ence of a Noether current\, dynamical aspects of QFT’s with non-compact
generalized symmetries\, scale vs conformal invariance and the Coleman-Man
dula theorem.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohsen Alishahiha
DTSTART:20220811T120000Z
DTEND:20220811T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/68
DESCRIPTION:Title: On Complexity Saturation for JT gravity with EOW brane\nby Mohs
en Alishahiha as part of CERN String Seminars\n\n\nAbstract\nWe consider t
he complexity of a single-sided AdS black hole as modelled by an end-of-th
e-world brane. We compute the complexity using a modified replica trick co
rresponding to the "quenched geodesic length" in JT gravity. The late time
behaviour of complexity shows a saturation to a constant value of order
𝑒𝑆0 following a period of linear growth. Furthermore\, we show that
our approach leads to an improved result for the variance of complexity\,
namely it being time-independent at late times.\n\nPlease note that there
will be no Zoom connection\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Diego Rodriguez-Gomez
DTSTART:20220809T120000Z
DTEND:20220809T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/69
DESCRIPTION:Title: Field theory defects through double scaling limits\nby Diego Ro
driguez-Gomez as part of CERN String Seminars\n\n\nAbstract\nDefect operat
ors in field theory are very interesting for a number of reasons. Drawing
inspiration from techniques which have been very recently applied to uncov
er interesting properties of sectors of operators with large charge under
a global symmetry\, we will study simple defects in the Wilson-Fisher fixe
d point near d=4\,6 dimensions. Combining with localization\, we will also
introduce a double-scaling limit for certain Wilson loops in N=2 supersym
metric theories in 4d which allows to make exact statements at finite N.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Silva
DTSTART:20220819T090000Z
DTEND:20220819T100000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/70
DESCRIPTION:Title: AdS Virasoro-Shapiro from dispersive sum rules\nby Joao Silva a
s part of CERN String Seminars\n\n\nAbstract\nWe consider the four-point c
orrelator of the stress-energy tensor in N=4 SYM\, to leading order in inv
erse powers of the central charge\, but including all order corrections in
1/lambda. This corresponds to the AdS version of the Virasoro-Shapiro amp
litude to all orders in the small alpha'/low energy expansion. Using dispe
rsion relations in Mellin space\, we derive an infinite set of sum rules.
These sum rules strongly constrain the form of the amplitude\, and determi
ne all coefficients in the low energy expansion in terms of the CFT data f
or heavy string operators\, in principle available from integrability. For
the first set of corrections to the flat space amplitude we find a unique
solution consistent with the results from integrability and localisation.
\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elias Kiritsis
DTSTART:20220829T120000Z
DTEND:20220829T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/71
DESCRIPTION:Title: Holographic QFTs on AdS\, wormholes and interfaces\nby Elias Ki
ritsis as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Avia Raviv-Moshe
DTSTART:20220906T130000Z
DTEND:20220906T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/72
DESCRIPTION:Title: Line Defects in CFTs: from Spin Impurities to Wilson Lines\nby
Avia Raviv-Moshe as part of CERN String Seminars\n\n\nAbstract\nIn this ta
lk\, we will consider line defects (one-dimensional defects) in CFTs. Such
systems are of relevance to various physical systems\, with applications
ranging from condensed matter physics to conformal gauge theories. I will
review some general properties of line defects in CFTs\, especially in the
context of RG flows on line defects\, where recent progress has been achi
eved. Then\, we will focus on two types of applications: models of spin im
purities and Wilson lines in conformal gauge theories.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Massimo Porrati
DTSTART:20220909T120000Z
DTEND:20220909T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/73
DESCRIPTION:Title: Partition Functions of Abelian Chern-Simons Theories on Handlebodie
s Partition Functions of Abelian Chern-Simons Theories on Handlebodies
\nby Massimo Porrati as part of CERN String Seminars\n\n\nAbstract\nThis t
alk reviews the use of radial quantization to compute Chern-Simons partiti
on functions on handlebodies of arbitrary genus. The partition function is
given by a particular transition amplitude between two states which are d
efined on the Riemann surfaces that define the (singular) foliation of the
handlebody. By requiring that the only singularities of the gauge field
inside the handlebody must be compatible with Wilson loop insertions\, we
find that the Wilson loop shifts the holonomy of the initial state. Togeth
er with an appropriate choice of normalization\, this procedure selects a
unique state in the Hilbert space obtained from a Kähler quantization of
the theory on the constant-radius Riemann surfaces. Radial quantization al
lows us to find the partition functions of Abelian Chern-Simons theories f
or handlebodies of arbitrary genus. For non-Abelian compact gauge groups\,
we show that our method reproduces the known partition function and Wilso
n loop VEVs at genus one.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shreya Vardhan
DTSTART:20220920T120000Z
DTEND:20220920T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/74
DESCRIPTION:Title: Non-isometric codes and effective field theory in the black hole in
terior\nby Shreya Vardhan as part of CERN String Seminars\n\n\nAbstrac
t\nI will argue that recent derivations of the Page curve for evaporating
black holes using the quantum extremal surface formula tell us that the bu
lk-to-boundary map at late times must be non-isometric. This implies that
a large set of states in the effective field theory Hilbert space of the b
lack hole interior do not exist in the fundamental description of the syst
em. Despite this\, I will show using a simple model that several features
of the effective field theory can be approximately preserved in the fundam
ental theory\, as long as we restrict to states and operators whose comple
xity is sub-exponential in the black hole entropy.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Venkatesa Chandrasekaran
DTSTART:20220927T120000Z
DTEND:20220927T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/75
DESCRIPTION:Title: Large N algebras and generalized entropy\nby Venkatesa Chandras
ekaran as part of CERN String Seminars\n\n\nAbstract\nI will discuss recen
t work on studying operator algebras in semiclassical gravity. In AdS/CFT\
, for two-sided black holes\, the large N limit of single-trace operators
in the boundary CFT results in a type III von Neumann algebra. Quantizing
the relative timeshift between the two boundaries and including this mode
in the algebra promotes it to type II\, which allows the von Neumann entro
py to be defined and calculated. I will first describe how this works for
semiclassical perturbations around the microcanonical TFD state\, and show
that the von Neumann entropy agrees with the generalized entropy of the b
lack hole. I will then apply the formalism to deSitter spacetime\, and dis
cuss implications for the entropy of the static patch.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Rudelius
DTSTART:20221004T120000Z
DTEND:20221004T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/76
DESCRIPTION:Title: Sharpening the Distance Conjecture in Diverse Dimensions\nby To
m Rudelius as part of CERN String Seminars\n\n\nAbstract\nThe Distance Con
jecture holds that any infinite-distance limit in the scalar field moduli
space of a consistent theory of quantum gravity must be accompanied by a t
ower of light particles whose masses scale exponentially with proper field
distance ||𝜙|| as 𝑚∼exp(−𝜆||𝜙||)\, where 𝜆 is order-on
e in Planck units. While the evidence for this conjecture is formidable\,
there is at present no consensus on which values of 𝜆 are allowed. In t
his talk\, I will propose a sharp lower bound on 𝜆 in 𝑑 spacetime di
mensions: 𝜆≥1/𝑑−2‾‾‾‾‾√. I will provide several line
s of evidence for this bound and discuss its implications for scalar field
potentials and cosmology.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Henry Lin
DTSTART:20221011T143000Z
DTEND:20221011T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/77
DESCRIPTION:Title: The bulk Hilbert space of double scaled SYK\nby Henry Lin as pa
rt of CERN String Seminars\n\n\nAbstract\nHow does the bulk Hilbert space
of quantum gravity emerge from a boundary theory? I take up this question
in the context of the SYK model in the double scaling limit. Berkooz et. a
l computed correlation functions in this model by summing chord diagrams.
By slicing open these chord diagrams\, I will explicitly construct the bul
k Hilbert space\; it resembles that of a lattice field theory where the le
ngth of the lattice is dynamical and determined by the chord number. Under
a calculable bulk-to-boundary map\, states of fixed chord number map to p
articular entangled 2-sided states with a corresponding size. This bulk re
construction is well-defined even when quantum gravity effects are importa
nt. Acting on the double scaled Hilbert space is a Type II_1 algebra of ob
servables\, which includes the Hamiltonian and matter operators. In the ap
propriate quantum Schwarzian limit\, we also identify the JT gravitational
algebra including the physical SL(2\,R) symmetry generators\, and obtain
explicit representations of the algebra using chord diagram techniques.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zahra Zahraee
DTSTART:20221018T120000Z
DTEND:20221018T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/78
DESCRIPTION:Title: Non-relativistic physics in AdS and its CFT dual\nby Zahra Zahr
aee as part of CERN String Seminars\n\n\nAbstract\nIn this talk we will di
scuss aspects of the non-relativistic two-body problems in AdS spacetime a
nd their CFT duals. Specifically\, we will define CFT correlation function
s that describe the NR dynamics in the bulk. We will then use them to unde
rstand the spectrum of double-twist operators as well as flat space scatt
ering.\n \nIn more detail\, we will see how the S-channel OPE expansion of
this correlator becomes the sum over states of the non-relativistic Hamil
tonian. We will then use this to understand the spectrum from quantum pert
urbation theory in the bulk. We will conclude this analysis by comparing o
ur result with the output from Lorentzian inversion formula. Lastly\, we
show how inserting an additional real time evolution in our correlator in
the flat space limit yields the usual scattering amplitude.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mr Ohad Mamroud
DTSTART:20221025T130000Z
DTEND:20221025T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/79
DESCRIPTION:Title: The Supersymmetric Index and its Holographic Interpretation\nby
Mr Ohad Mamroud as part of CERN String Seminars\n\n\nAbstract\nThe supers
ymmetric index of N=4 SU(N) Super Yang-Mills is a well studied quantity. I
n 2104.13932\, we analyzed it using the Bethe Ansatz approach\, expressed
it as a sum and concentrated on some family of contributions to it. In the
large N limit each term in this family corresponds to the contribution of
a different euclidean black hole to the partition function of the dual gr
avitational theory. By taking into account non-perturbative contributions
(wrapped D3-branes)\, we further showed a one to one match between the con
tributions of the gravitational saddles and this family of contributions t
o the index\, both at the perturbative and non-perturbative levels. I'll e
nd with some newer results\, concerning the form of these terms at finite
N\, and new solutions to the Bethe Ansatz equations (i.e. additional contr
ibutions to the index beyond the ones described in that paper).\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:José Calderón-Infante
DTSTART:20221101T130000Z
DTEND:20221101T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/80
DESCRIPTION:Title: Pushing the Limits of the Swampland Distance Conjecture\nby Jos
é Calderón-Infante as part of CERN String Seminars\n\n\nAbstract\nThe go
al of this talk is to push the limits of the Swampland Distance Conjecture
(SDC). This is one of the most relevant conjectures in the Swampland prog
ram\, whose aim is to identify the criteria that an effective field theory
must satisfy in order to be consistently coupled to quantum gravity. For
this purpose\, we study the SDC in two different contexts: Running solutio
ns and AdS/CFT.\n\nWe start by presenting a first example of running solut
ion and its interplay with the SDC. Inspired by this\, we propose that con
sistency of the SDC along the RG flow of the theory imposes constraints on
the potentials that are attainable in quantum gravity. By studying this c
onstraints\, a new formulation of this conjecture is elucidated: the Conve
x Hull SDC. We then move to another type of running solutions\, the so-cal
led dynamical cobordisms. They receive this name for being the spacetime r
ealization of cobordisms between different theories. We uncover some unive
rsal behavior for dynamical cobordisms to nothing\, and relate them to the
Distance\, Cobordism and asymptotic dS conjectures. Finally\, we turn our
attention to the SDC in the context of AdS/CFT. From the CFT perspective\
, this conjecture is naturally realized at weak coupling points in which s
ome sector decouples. We then perform some purely CFT analysis in the cont
ext of 4d \\mathcal{N}=2 theories. This provides the first piece of eviden
ce for the SDC beyond String Theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Florian Loebbert
DTSTART:20221122T130000Z
DTEND:20221122T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/81
DESCRIPTION:Title: Fishnet Integrals from Integrability and Geometry\nby Florian L
oebbert as part of CERN String Seminars\n\n\nAbstract\nThe computation of
Feynman integrals still represents a bottle neck for precision calculation
s in quantum field theory. Recent progress goes hand in hand with the unde
rstanding of new function classes and their mathematical structure. In thi
s talk we discuss the so-called fishnet integrals that represent an infini
te family of scalar Feynman integrals featuring integrable structures. In
particular we review the Yangian quantum group symmetry of these integrals
which extends the conformal spacetime symmetry of the associated fishnet
quantum field theories. We then focus on the specific case of fishnets in
two spacetime dimensions and argue that these integrals compute the quantu
m volumes of Calabi-Yau varieties. Here the Yangian provides a convenient
tool that yields the Picard-Fuchs differential equations for the Calabi-Ya
u periods\, while the geometry dictates the particular linear combination
of periods\, which furnishes the Feynman integrals.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefano Negro
DTSTART:20221129T103000Z
DTEND:20221129T113000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/82
DESCRIPTION:Title: Topological gauging and non-relevant deformations of Quantum Field
Theories\nby Stefano Negro as part of CERN String Seminars\n\n\nAbstra
ct\nn the last few years\, much attention has been devoted to the study of
a peculiar class of irrelevant deformations of 2-dimensional Quantum Fiel
d Theories\, known as “Solvable Irrelevant Deformations”. The poster c
hild of these is the celebrated “TTbar deformation”. They display unus
ual properties in the UV\, which can be described exactly\, their irreleva
nt nature notwithstanding. For this reason they represent a sensible exten
sion of Quantum Field Theory beyond the Wilsonian paradigm and have attrac
ted a considerable attention from the high energy theory community. The pr
operty of being solvable is shared with a wider class of deformations\, co
nstructed out of pairs of conserved currents. In general these are margina
l deformations\, thus presenting very different UV properties. Nonetheless
their structures are similar to the TTbar ones\, hinting at the existence
of a universal description.\n \nIn this talk I will present a very genera
l framework that accommodates both solvable irrelevant and solvable margin
al deformations\, which amounts to a “topological gauging” of the symm
etries of the system. Through simple path integral computations\, I will r
ecover the main features of these theories and show their equivalence to T
ST and Yang-Baxter deformations. For the case of TTbar\, the topological g
auging perspective explains the previously not understood relation to fiel
d theory in non-commutative Minkowski space-time and to the centrally exte
nded Poincaré algebra.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/82/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alvaro Herraez
DTSTART:20221201T130000Z
DTEND:20221201T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/83
DESCRIPTION:Title: The Emergence Proposal in Quantum Gravity and the Species Scale
\nby Alvaro Herraez as part of CERN String Seminars\n\n\nAbstract\nThe Eme
rgence Proposal claims that in Quantum Gravity the kinetic terms of the fi
elds in the IR can be understood as emergent from integrating out (infinit
e) towers of particles up to the QG cutoff. After introducing this proposa
l in the context of the Swampland Program and its relation to the Distance
and Weak Gravity Conjectures\, I will explain why it is natural to identi
fy this QG cutoff with the Species Scale\, motivating it by direct computa
tion in the presence of the relevant towers. Then\, I will present evidenc
e for this proposal by directly studying how it is realized in different s
tring theory setups\, where the kinetic terms of scalars\, p-forms and eve
n scalar potentials can be shown to be consistent with emergence after int
egrating out such towers.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter
DTSTART:20221206T130000Z
DTEND:20221206T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/84
DESCRIPTION:Title: Large p from SL(2\,Z)\nby Eric Perlmutter as part of CERN Strin
g Seminars\n\n\nAbstract\nWe present formulas for a family of integrated c
orrelators in 4d maximally supersymmetric SU(N) super Yang-Mills theory\,
labeled by arbitrary rank N and arbitrary SU(4) charge p. This gives rise
to exact results at large charge\, for any rank N and complexified gauge c
oupling \\tau (including various double-scaling limits). We discuss featur
es of this expansion\, and contrast with known results for extremal two-po
int functions in superconformal QCD. Our computations are greatly facilita
ted by the use of SL(2\,Z) spectral theory.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Tonni
DTSTART:20221213T130000Z
DTEND:20221213T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/85
DESCRIPTION:Title: Entanglement entropies for Lifshitz fermionic fields at finite dens
ity\nby Erik Tonni as part of CERN String Seminars\n\n\nAbstract\nThe
entanglement entropies of an interval for the free fermionic spinless Schr
oedinger field theory at finite density and zero temperature are investiga
ted. The interval is either on the line or at the beginning of the half li
ne\, when either Neumann or Dirichlet boundary conditions are imposed at t
he origin. We show that the entanglement entropies are finite functions of
a dimensionless parameter proportional to the area of the rectangular reg
ion in the phase space identified by the Fermi momentum and the length of
the interval. \nFor the interval on the line\, the entanglement entropy i
s a monotonically increasing function. Instead\, for the interval on the h
alf line\, it displays an oscillatory behaviour related to the Friedel osc
illations of the mean particle density at the entangling point. \nBy empl
oying the properties of the prolate spheroidal wave functions or the expan
sions of the tau functions of the kernels occurring in the spectral proble
ms\, determined by the two point function\, we find analytic expressions f
or the expansions of the entanglement entropies in the asymptotic regimes
of small and large area of the rectangular phase space region. Extending o
ur analysis to a class of free fermionic Lifshitz models\, we find that th
e parity of the Lifshitz exponent determines the properties of the biparti
te entanglement.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/85/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ji Hoon Lee
DTSTART:20230117T153000Z
DTEND:20230117T173000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/86
DESCRIPTION:Title: Computing bulk microstates\nby Ji Hoon Lee as part of CERN Stri
ng Seminars\n\n\nAbstract\nA central question in AdS/CFT is how the string
degrees of freedom are organized in the dual gauge theory. In my talk\, I
present an exact formula that relates the BPS sectors of U(N) gauge theor
ies and their string duals. The formula expresses the finite N superconfor
mal index of a U(N) gauge theory as a sum over stacks of bulk giant gravit
on branes. I explain how to holographically construct the indices of bulk
string/brane configurations by analyzing the modifications of determinant
operators in gauge theory. Finally\, I discuss implications for black hole
s and the bulk BPS Hilbert space. Based on 2109.02545 and 2204.09286.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arjun Kar
DTSTART:20230124T153000Z
DTEND:20230124T173000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/87
DESCRIPTION:Title: A Celestial Matrix Model\nby Arjun Kar as part of CERN String S
eminars\n\n\nAbstract\nUnderstanding the proper formulation of AdS hologra
phy in two spacetime dimensions has led to fascinating progress in several
directions. The main novel ingredient compared to higher dimensions is t
hat the asymptotic behavior of the metric is only "nearly'' AdS in a certa
in precise sense. This difference allows for a very simple theory\, Jacki
w-Teitelboim gravity\, to have a non-perturbative completion as a Hermitia
n matrix model. In this talk\, we propose analogous modifications of the
flat space boundary conditions in two dimensional dilaton gravity. These
modifications allow a very simple theory\, which we call Cangemi-Jackiw gr
avity\, to have a non-perturbative completion as a random matrix model. W
e will discuss the Lorentzian and Euclidean formulations of this model\, c
hallenges in computing its non-perturbative scattering matrix\, and which
of its lessons are potentially applicable to four-dimensional celestial ho
lography.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Murat Kologlu
DTSTART:20230131T153000Z
DTEND:20230131T173000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/88
DESCRIPTION:Title: Quantum Detectorology\nby Murat Kologlu as part of CERN String
Seminars\n\n\nAbstract\nI will talk about recent work studying asymptotic
detector operators in weakly-coupled field theories. Detector operators de
scribe measurements that can be performed at future null infinity in a col
lider experiment. The set of detectors depends on the dynamics of the theo
ry. In a conformal field theory\, detectors are identified with light-ray
operators\, thus bearing a direct relation to the spectrum of the theory.
I will discuss how to renormalize the infrared divergences of general dete
ctor operators in perturbation theory\, leading to detector anomalous dime
nsions. Our formalism allows for the resolution of intersections of Regge
trajectories where nontrivial mixing occurs. Working with the Wilson-Fishe
r theory as an example\, I will present an explicit expression for the Pom
eron light-ray operator\, as well as an improved prediction for the Regge
intercept. Finally\, I will discuss novel “Reggeized scalar” trajector
ies.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kristan Jensen
DTSTART:20230207T153000Z
DTEND:20230207T173000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/89
DESCRIPTION:Title: A precision test of averaging in AdS/CFT\nby Kristan Jensen as
part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Paletta
DTSTART:20230214T130000Z
DTEND:20230214T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/90
DESCRIPTION:Title: Introduction to open quantum systems\nby Chiara Paletta as part
of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Iliesiu
DTSTART:20230221T130000Z
DTEND:20230221T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/91
DESCRIPTION:Title: Black hole microstate counting from the gravitational path integral
\nby Luca Iliesiu as part of CERN String Seminars\n\n\nAbstract\nRepro
ducing the integer count of black hole micro-states from the gravitational
path integral is an important problem in quantum gravity. In this paper\,
we show that\, by using supersymmetric localization\, the gravitational p
ath integral for 1/16-BPS black holes in supergravity reproduces the index
obtained in the string theory construction of such black holes\, includin
g all non-perturbatively suppressed geometries. A more refined argument th
en shows that not only the black hole index but also the total number of b
lack hole microstates within an energy window above extremality that is po
lynomially suppressed in the charges also matches this string theory index
. To achieve such a match\, we compute the one-loop determinant arising in
the localization calculation for all N=2 supergravity supermultiplets in
the N=8 gravity supermultiplet. Furthermore\, we carefully account for the
contribution of boundary zero-modes\, which can be seen as arising from t
he zero-temperature limit of the N=4 super-Schwarzian\, and show that perf
orming the exact path integral over such modes provides a critical contrib
ution needed for the match to be achieved.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Delacretaz
DTSTART:20230228T130000Z
DTEND:20230228T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/92
DESCRIPTION:Title: Nonlinear Effective Field Theory of Fermi Liquids\nby Luca Dela
cretaz as part of CERN String Seminars\n\n\nAbstract\nLandau's theory of F
ermi liquids is a cornerstone of theoretical physics. I will show how to f
ormulate Fermi liquid theory as an effective field theory of bosonic degre
es of freedom\, using the mathematical formalism of coadjoint orbits. Whil
e at the linear level\, this theory reduces to existing multidimensional b
osonization approaches\, it necessarily features nonlinear corrections tha
t are fixed by the geometry of the Fermi surface. These are crucial to rep
roduce nonlinear response\, such as higher-point functions of currents. Th
e effective field theory framework furthermore systematically parametrizes
corrections to Fermi liquid behavior\, and provides a computationally adv
antageous approach for non-Fermi liquids -- strongly interacting fixed poi
nts obtained by deforming Fermi liquids with relevant interactions.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/92/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomašević
DTSTART:20230307T130000Z
DTEND:20230307T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/93
DESCRIPTION:Title: Holographic duals of evaporating black holes\nby Marija Tomaše
vić as part of CERN String Seminars\n\n\nAbstract\nWe describe the dynami
cal evaporation of a black hole as the classical evolution in time of a bl
ack hole in an Anti-de Sitter braneworld. A bulk black hole whose horizon
intersects the brane yields the classical bulk dual of a black hole couple
d to quantum conformal fields. The evaporation of this black hole happens
when the bulk horizon slides off the brane\, making the horizon on the bra
ne shrink. We use a large-D effective theory of the bulk Einstein equation
s to solve the time evolution of these systems. With this method\, we stud
y the dual evaporation of a variety of black holes interacting with colder
radiation baths. We also obtain the dual of the collapse of holographic r
adiation to form a black hole on the brane.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Lupsasca
DTSTART:20230314T130000Z
DTEND:20230314T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/94
DESCRIPTION:Title: The Black Hole Photon Ring\nby Alex Lupsasca as part of CERN St
ring Seminars\n\n\nAbstract\nWhat does a black hole look like? The first i
mages of the supermassive black hole M87* display a bright ring encircling
the event horizon\, which appears as a dark patch in its surrounding emis
sion. But Einstein's theory of general relativity predicts that within thi
s image there also lies a thin "photon ring" consisting of multiple mirror
images of the main emission. These images arise from photons that orbited
around the black hole multiple times\, probing the warped space-time geom
etry just outside its horizon. The photon ring carries an imprint of the s
trong gravity in this region and encodes fundamental properties of the bla
ck hole (including\, for instance\, its quasinormal mode spectrum). A meas
urement of this predicted (but not yet observed) ring could provide a prec
ise test of general relativity and will be the target of a NASA mission pr
oposed to fly within the next decade.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Stout
DTSTART:20230321T130000Z
DTEND:20230321T150000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/95
DESCRIPTION:Title: Infinite Distance Limits and Factorization\nby John Stout as pa
rt of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Timo Weigand
DTSTART:20230328T120000Z
DTEND:20230328T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/96
DESCRIPTION:Title: Quantum Gravity Bounds on 4D EFTs with Minimal Supersymmetry\nb
y Timo Weigand as part of CERN String Seminars\n\n\nAbstract\nAccording to
the Swampland idea\, quantum gravity effects put severe constraints on ef
fective field theories beyond the usual consistency conditions from quantu
m field theory such as absence of gauge or gravitational anomalies. In thi
s talk\, we propose such constraints for four-dimensional N=1 supergraviti
es based on consistency of certain axionic\, or EFT\, strings. These are c
ertain strings which are magnetically charged under the axionic components
of the chiral N=1 superfields\; their existence follows from the Complet
eness Conjecture in quantum gravity. The key observation is that anomaly i
nflow from the four-dimensional theory to the string worldsheet induces an
omalies on the string which must be cancelled by local anomalies on the st
ring. This results in various quantisation conditions as well as bounds on
the signs of axionic couplings in the supergravity\, including the sign o
f the Gauss-Bonnet term\, and also bounds on the rank of the gauge group i
n terms of these Gauss-Bonnet couplings. These constraints can rule out su
pergravity theories which otherwise look perfectly healthy as effective f
ield theories of quantum gravity. We also test the proposed constraints by
comparing them with explicit string models\, in particular with F-theory
compactifications to four dimensions.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Beatrix Mühlmann
DTSTART:20230404T120000Z
DTEND:20230404T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/97
DESCRIPTION:Title: Matrix duality in twistor space\nby Beatrix Mühlmann as part o
f CERN String Seminars\n\n\nAbstract\nIn this talk I consider loop integra
nds for correlators of “master” operators in N=4 SYM. Loop integrands
are Born-level correlators in the self-dual sector\nof N = 4 SYM\, while
master operators are determinant operators which serve as generating funct
ions of all single-trace half-BPS operators. \nWorking in twistor space an
d using matrix duality I will reformulate these integrands in terms of a m
atrix integral which also manifests a\n10 dimensional structure that combi
nes spacetime and R-charge symmetries.\n\nThis talk is based on work in pr
ogress with S. Caron-Huot and F. Coronado.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/97/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu
DTSTART:20230411T090000Z
DTEND:20230411T110000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/98
DESCRIPTION:Title: TH String Theory Seminar\nby Jie Gu as part of CERN String Semi
nars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sunil Mukhi
DTSTART:20230425T120000Z
DTEND:20230425T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/99
DESCRIPTION:Title: Classification of Rational Conformal Field Theories With A Single C
ritical Exponent\nby Sunil Mukhi as part of CERN String Seminars\n\nAb
stract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/99/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jacob McNamara
DTSTART:20230502T143000Z
DTEND:20230502T163000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/100
DESCRIPTION:Title: Reflections on Parity Breaking\nby Jacob McNamara as part of C
ERN String Seminars\n\n\nAbstract\nOne approach to the Strong CP Problem (
known as Nelson-Barr models) is to assume that parity is a gauge symmetry\
, which is spontaneously broken in the world around us. In this talk\, I w
ill argue that the domain walls formed from spontaneous parity breaking ar
e exactly stable. This stability can be understood as the result of an unu
sual sort of conserved charge\, which has features in common with both gau
ge charges and global charges. We will explain how these charges are compa
tible with the expected absence of global symmetries in quantum gravity\,
as well as their relationship with the Swampland Cobordism Conjecture.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomáš Procházka
DTSTART:20230509T120000Z
DTEND:20230509T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/101
DESCRIPTION:Title: Bethe ansatz in 2d conformal field theory\nby Tomáš Procház
ka as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin
DTSTART:20230516T143000Z
DTEND:20230516T163000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/102
DESCRIPTION:Title: The statistics of spins for CFTs\nby Nathan Benjamin as part o
f CERN String Seminars\n\n\nAbstract\nI will discuss universal behavior of
CFT data at high energies. In particular I will discuss universal formula
s for both the entropy and the three-point-functions of local operators fo
r d-dimensional CFT (d>2) as a function of energy and spin\, using a techn
ique called thermal effective field theory. This result can be thought of
as a higher-dimensional version of Cardy's formula for 2d CFTs. I will als
o discuss holographic interpretations of this result. Based on work to app
ear with J. Lee\, H. Ooguri\, and D. Simmons-Duffin.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sašo Grozdanov
DTSTART:20230523T120000Z
DTEND:20230523T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/103
DESCRIPTION:Title: Spectra\, reconstructions and pole-skipping\nby Sašo Grozdano
v as part of CERN String Seminars\n\n\nAbstract\nThe poles of two-point fu
nctions in momentum space\, which can be computed and analysed using holog
raphic methods\, reveal various details of the physical properties of spec
tra in QFTs. In thermal QFTs\, the lowest-energy (IR) gapless mode is usua
lly described by the theory of hydrodynamics. Assuming a known dispersion
relation of only a single hydrodynamic mode\, I will discuss when and how
the reconstruction of the complete spectrum of physical excitations is pos
sible in the corresponding correlator. In particular\, I will demonstrate
our recently developed constructive algorithm based on the theorems of Dar
boux and Puiseux that allows for a reconstruction of all modes connected b
y `level-crossings’ in the associated spectral curve\, from IR to UV. In
the second part of my talk\, I will introduce the phenomenon of pole-skip
ping (formally\, a “0/0”) in such correlators and discuss how its know
ledge can itself be sufficient to reconstruct the entire spectrum.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nima Lashkari
DTSTART:20230620T120000Z
DTEND:20230620T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/104
DESCRIPTION:Title: Information loss\, and emergent type III1 algebras in time\nby
Nima Lashkari as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sumit Das
DTSTART:20230718T120000Z
DTEND:20230718T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/105
DESCRIPTION:Title: Entanglement of Internal Degrees of Freedom\, Finiteness and Holog
raphy\nby Sumit Das as part of CERN String Seminars\n\n\nAbstract\nI w
ill discuss notions of entanglement of internal degrees of freedom in theo
ries of large N matrices. Along with usual base space entanglement\, this
kind of entanglement (which do not pertain to a subregion of base space) s
hould play a key role in holography\, particularly in the emergence of a s
mooth internal space in the bulk. One such notion is target space entangle
ment\, which appears as entanglement of D branes in the bulk. For the c=1
Matrix Model we will show how the target space entanglement entropy is per
turbatively divergent\, but non-perturbatively finite. Yet another notion
relates to geometriztion of internal symmetries\, as in familiar examples
of holography n AdS X Y. We provide evidence that the entropy of this kin
d of entanglement is measured by Ryu-Takayanagi surfaces which are smeared
along the AdS directions\, and anchored on a subregion of the internal sp
ace Y.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony
DTSTART:20231009T140000Z
DTEND:20231009T160000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/106
DESCRIPTION:Title: Correlation functions in TT*-deformed conformal field theories
\nby Ofer Aharony as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vasilis Niarchos
DTSTART:20231010T120000Z
DTEND:20231010T140000Z
DTSTAMP:20260422T212528Z
UID:CERNStringSem/107
DESCRIPTION:Title: Bootstrability with Improved Truncation Methods\nby Vasilis Ni
archos as part of CERN String Seminars\n\n\nAbstract\nI will discuss recen
t work on the numerical conformal bootstrap that modifies the scope of the
so-called truncation methods and improves their efficiency. I will show h
ow the proposed approach performs in the recently discussed context of boo
tstrability for 1d defect CFTs on 1/2 BPS Wilson lines in 4d N=4 SYM theor
y\, how it compares with the more standard linear functional method and ho
w different algorithms allow us to tackle the large-scale non-convex optim
ization problems that are involved in this method. Along the way\, I will
address the prospects of AI and Machine Learning in this particular direct
ion.\n
LOCATION:https://researchseminars.org/talk/CERNStringSem/107/
END:VEVENT
END:VCALENDAR