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BEGIN:VEVENT
SUMMARY:Sameer Murthy (Kings College London)
DTSTART:20200526T120000Z
DTEND:20200526T130000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/1
DESCRIPTION:Title: The growth of the 1/16-BPS index in N=4 Super Yang-Mills\
nby Sameer Murthy (Kings College London) as part of CERN String Seminars\n
\n\nAbstract\nI will discuss the superconformal index that counts states p
reserving 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 dou
ble trace operators in the action. The AdS/CFT correspondence predicts tha
t the index should have exponential growth at large charges and large N\,
corresponding to the 1/16-BPS black hole (BH) in AdS5. I will present anal
ytical and numerical analyses of the matrix model which clearly show this
expected 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 i
nteresting relations with the Bloch-Wigner dilogarithm\, a function introd
uced by number theorists. \nFinally\, using techniques from representation
theory\, I will show that the finite-N index actually interpolates betwee
n counting multi-gravitons at small charge and BHs at large charge.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michele Del Zotto
DTSTART:20200616T120000Z
DTEND:20200616T130000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/2
DESCRIPTION:Title: Higher form symmetries and M theory\nby Michele Del Zotto
as part of CERN String Seminars\n\n\nAbstract\nWhat is the stringy origin
of discrete higher form symmetries of quantum field theories? In this tal
k we will discuss the answer to this question in terms of defect groups fr
om geometric engineering in M-theory. Flux non-commutativity in M-theory g
ives rise to (mixed) ’t Hooft anomalies for the defect group\, which con
strains the corresponding global structures of the associated quantum fiel
ds. Examples of applications in various dimensions will be given\, with sp
ecial emphasis on the case of 5d SCFTs.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Maloney
DTSTART:20200623T140000Z
DTEND:20200623T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/3
DESCRIPTION:Title: Gravity from Averaging CFTs\nby Alex Maloney as part of C
ERN String Seminars\n\n\nAbstract\nI will explore the idea that certain th
eories of gravity in Anti-de\nSitter space are dual to an average over an
ensemble of quantum\ntheories\, rather than to a specific quantum theory.
I will describe\nan average over Narain’s family of two-dimensional con
formal field\ntheories which describe free bosons on a torus\, and compute
the\npartition function using the Siegel-Weil formula. The result takes\
nthe form of a sum over geometries as one would expect in a theory of\ngra
vity. But the gravitational theory looks more like a Chern-Simons\ntheor
y than like Einstein gravity.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Andriot
DTSTART:20200707T130000Z
DTEND:20200707T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/4
DESCRIPTION:Title: Do classical de Sitter string backgrounds exist?\nby Davi
d Andriot as part of CERN String Seminars\n\n\nAbstract\nA classical solut
ion of string theory with a 4d de Sitter space-time could provide a simple
and well-controlled setting to establish a connection to cosmological mod
els. 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 plag
ued by many no-go theorems\, or by the difficulty for concrete 10d supergr
avity solutions to fit in the classical stringy regime. This situation agr
ees with the recent claims of de Sitter swampland conjectures. These conje
ctures can actually be verified quantitatively\, with a surprisingly good
agreement\, as will be shown. This may hint at a deep reason against class
ical de Sitter background\, possibly to be found within the web of swampla
nd conjectures\, and the relation to the distance conjecture will briefly
be commented on.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julian Sonner
DTSTART:20200811T120000Z
DTEND:20200811T130000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/5
DESCRIPTION:Title: Causal symmetry breaking: late time physics of holographic qu
antum chaos\nby Julian Sonner as part of CERN String Seminars\n\n\nAbs
tract\nQuantum chaotic systems are often defined via the assertion that th
eir spectral statistics coincides with\, or is well approximated by\, rand
om matrix theory. In this talk I will explain how the universal content of
random matrix theory emerges as the consequence of a simple symmetry-brea
king principle and its associated Goldstone modes. Within AdS/CFT this giv
es a universal framework to express correlations between ``different unive
rses’’\, even for individual theories rather than ensembles. I will Il
lustrate the bulk picture of this EFT using the example minimal string the
ory. I will end by discussing the construction of the EFT of quantum chaos
also in higher dimensional field theories\, as applicable for example for
higher-dimensional AdS/CFT dual pairs.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jordan Cotler
DTSTART:20200922T140000Z
DTEND:20200922T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/6
DESCRIPTION:Title: Euclidean Wormholes and Random CFT\nby Jordan Cotler as p
art of CERN String Seminars\n\n\nAbstract\nWe will nonperturbatively compu
te the path integral of 3D gravity with negative cosmological constant on
spaces which are topologically a torus times an interval. These are Euclid
ean wormholes\, which smoothly interpolate between two asymptotically Eucl
idean AdS3 regions with torus boundary. The resulting amplitude encodes s
pectral correlations between BTZ black hole microstates near threshold. T
he low-energy limit of these correlations is precisely that of a double-sc
aled random matrix ensemble with Virasoro symmetry. These findings suggest
that if pure 3D gravity has a holographic dual\, then the dual is an ense
mble which generalizes random matrix theory. We will also show that there
are analogs of these 3D wormholes in higher dimensions and discuss their
stability in pure Einstein gravity as well as string theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero
DTSTART:20200929T120000Z
DTEND:20200929T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/7
DESCRIPTION:Title: Cobordisms\, anomalies\, and the Swampland in d>6\nby Mig
uel Montero as part of CERN String Seminars\n\n\nAbstract\nThe Swampland p
rogram aims at constraining the EFTs that can be consistently coupled to q
uantum gravity from general principles. In particular cases\, absence of g
lobal symmetries can lead to strong constraints at low energies. In this t
alk I will explain how and illustrate this in the particular context of su
persymmetric theories in d>6. In particular\, vanishing of certain cobordi
sm classes requires existence of singular defects\, which we call "I-folds
". I-fold compactifications can have anomalies\, rendering the theory inco
nsistent. In this way\, we find additional constraints in the rank of the
gauge group in d>6. In d>7\, our constraints are very restrictive\, and th
e only solutions are precisely realized by the known string compactificati
ons to 8d and 9d. This establishes the "String Lamppost Principle"\, the i
dea that the only consistent quantum gravities are string compactification
s\, in d>7 on a generic point of the Coulomb branch. I will also briefly c
omment on applications of these techniques to other interesting setups.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matthew Dodelson
DTSTART:20201006T120000Z
DTEND:20201006T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/8
DESCRIPTION:Title: Singularities of thermal correlators at strong coupling\n
by Matthew Dodelson as part of CERN String Seminars\n\n\nAbstract\nI will
describe work in progress with Ooguri on the singularities of the two poin
t function at finite temperature in a conformal field theory in more than
two dimensions. At weak coupling the only singularity is on the light cone
\, but in the large N\, large lambda regime a new singularity emerges. Thi
s new singularity corresponds to a null geodesic in the AdS/Schwarzschild
black hole\, which may wrap the photon sphere many times. After deriving t
his result\, I will discuss the resolution of these singularities by strin
gy tidal effects at finite lambda. The basic tool I will use is to take th
e Penrose limit around a given null geodesic\, and then use the solubility
of the string theory in this background. I will also discuss applications
to rotating black holes.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Craig Lawrie
DTSTART:20201020T140000Z
DTEND:20201020T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/9
DESCRIPTION:Title: Integrability in 6D SCFTs\nby Craig Lawrie as part of CER
N String Seminars\n\n\nAbstract\n6D superconformal field theories associat
ed to long generalized quivers have a large R-charge sector\; we find evid
ence that operator mixing in this sector is governed by a 1D spin chain Ha
miltonian with operator scaling dimensions controlled by a perturbation se
ries in inverse powers of the R-charge. When the 6D SCFT is rank R (G\, G)
conformal matter we study a class of operators where the mixing is contro
lled by the integrable open Heisenberg XXX_s spin chain\, with the spin s
depending 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 in
dividual conformal matter building blocks\, derive the integrable Hamilton
ian capturing the operator mixing\, determine the anomalous dimensions of
one class of operators\, and give a variety of future directions in which
the putative integrable structure of 6D SCFTs can be tested and explored.\
n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou
DTSTART:20201013T130000Z
DTEND:20201013T140000Z
DTSTAMP:20260404T093135Z
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 pre
sent a holographic framework for reconstructing the experience of bulk obs
ervers in AdS/CFT. In particular\, I will show how to recover the proper t
ime and energy distribution measured along bulk worldlines\, directly in t
he CFT via a universal\, background-independent prescription. For an obser
ver falling into an eternal AdS black hole\, the proposal resolves a conce
ptual puzzle raised by Marolf and Wall. Notably\, the prescription does no
t rely on an external dynamical Hamiltonian or the AdS boundary conditions
and is\, therefore\, outlining a general framework for the emergence of t
ime."\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Johanna Erdmenger
DTSTART:20201027T130000Z
DTEND:20201027T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/11
DESCRIPTION:Title: Resolving the modular flow for free fermions\nby Johanna
Erdmenger as part of CERN String Seminars\n\n\nAbstract\nModular flow is
a symmetry 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 be
yond highly symmetric cases. The key new element presented in this talk is
a new formula for modular flows for free chiral fermions in 1+1 dimension
s. This is obtained from the resolvent\, a standard technique in complex a
nalysis. We present novel results -- not fixed by conformal symmetry -- fo
r disjoint regions on the plane\, cylinder and torus. Depending on tempera
ture and boundary conditions\, these display different behaviour ranging f
rom purely local to non-local in relation to the mixing of operators at sp
acelike separation. We also discuss the modular two-point function\, whos
e analytic structure is in precise agreement with the KMS condition that g
overns modular evolution. The ready-to-use formulae presented may provide
new ingredients to explore the connection between spacetime and entangleme
nt.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Blommaert
DTSTART:20201110T160000Z
DTEND:20201110T180000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/12
DESCRIPTION:Title: Dissecting the ensemble in JT gravity\nby Andreas Blomma
ert as part of CERN String Seminars\n\n\nAbstract\nWe discuss the role of
wormholes and branes in reconciling geometry with quantum mechanics\, base
d on recent developments in JT gravity\, an analytically solvable model of
quantum gravity in two dimensions. First\, we will see how wormholes enab
le geometry to accurate capture averaged correlators of chaotic quantum sy
stems. Because these are averaged properties\, naively wormholes in gravit
ational theories imply some ensemble interpretation of those theories. How
ever\, we will see that the geometrical description of individual quantum
systems involves not just wormholes\, but also some background branes. The
se branes encode the microstructure of some given quantum system in bulk g
eometry and collapse the ensemble.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kazumi Okuyama
DTSTART:20201117T100000Z
DTEND:20201117T120000Z
DTSTAMP:20260404T093135Z
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 func
tion of Jackiw-Teitelboim (JT)\ngravity using the matrix model description
recently found by Saad\,\nShenker and Stanford. We show that the partitio
n function of JT\ngravity is written as the expectation value of a macrosc
opic loop\noperator in the old matrix model of 2d gravity in the backgroun
d where\ninfinitely many couplings are turned on in a specific way. Based
on\nthis expression we develop a very efficient method of computing the\np
artition function in the genus expansion as well as in the low\ntemperatur
e expansion by making use of the Korteweg-de Vries\nconstraints obeyed by
the partition function. \nWe also generalize our analysis to the case of
multi-boundary\ncorrelators with the help of the boundary creation operato
r. We\nformulate a method of computing it up to any order and also find a
\nuniversal form of the two-boundary correlator in terms of the error\nfun
ction. Using this result we are able to write down the analytic\nform of t
he spectral form factor in JT gravity and show how the ramp\nand plateau b
ehavior arises.\nThis talk is based on the work with Kazuhiro Sakai (arXiv
:1911.01659\,arXiv:2004.07555)\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Levine
DTSTART:20201124T130000Z
DTEND:20201124T150000Z
DTSTAMP:20260404T093135Z
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 rev
ealing the entanglement wedge using simple operations. We ask what operati
on a semiclassical observer can do to bring the entanglement wedge into ca
usal contact with the boundary\, via backreaction. In a generic perturbati
ve class of states\, we propose a unitary operation in the causal wedge wh
ose backreaction brings all of the previously causally inaccessible `penin
sula' into causal contact with the boundary. This class of cases includes
entanglement wedges associated to boundary sub-regions that are unions of
disjoint spherical caps\, and the protocol works to first order in the siz
e of the peninsula. The unitary is closely related to the so-called Connes
Cocycle flow\, which is a unitary that is both well-defined in QFT and lo
calised to a sub-region. Our construction requires a generalization of the
work by Ceyhan & Faulkner to regions which are unions of disconnected sph
erical caps. We argue that this cocycle should be thought of as naturally
generalizing the non-local coupling introduced in the work of Gao\, Jaffer
is & Wall. If time permits we will discuss forthcoming work which attempts
at studying the quantum extremal surface position for bulk theories duel
to a sub-maximally chaotic boundary theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lara Anderson
DTSTART:20201201T130000Z
DTEND:20201201T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/15
DESCRIPTION:Title: Topological Textures in Heterotic Theories\nby Lara Ande
rson as part of CERN String Seminars\n\n\nAbstract\nIn this talk I will re
view the ways that compactifications of the heterotic string can be subjec
t to constraints on the matter couplings of the 4-dimensional effective th
eory that do not arise from gauge symmetries. Such "topological vanishings
" have the potential to be useful for the realization of certain mass hier
archies (such as in the famous "mu problem") or dangerously restrictive on
the physical theories. I will describe and compare several different ways
that topological vanishings arise in heterotic theories and new results t
hat indicate they may be a generic feature of such compactifications.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alfred Shapere
DTSTART:20201208T150000Z
DTEND:20201208T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/16
DESCRIPTION:Title: Quantum Error-Correcting Codes and Narain CFTs\nby Alfre
d Shapere as part of CERN String Seminars\n\n\nAbstract\nThere is a rich w
eb of connections between classical error-correcting codes\, Euclidean lat
tices\, and chiral conformal field theories. I will explain an analogous r
elationship between quantum error-correcting codes\, Lorentzian lattices\,
and nonchiral CFTs arising from toroidal compactifications of strings. Sp
ecifically\, I will show how quantum stabilizer codes are embedded in the
operator algebras of associated Narain CFTs. With respect to “code” CF
Ts\, the constraints of modular invariance reduce to simple algebraic equa
tions. Solving these equations provides many examples of physically distin
ct CFTs with the same spectrum\; we also find many solutions that do not c
orrespond 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 in general\, a solution of the bootstrap equations implies neither t
he existence nor the uniqueness of a corresponding CFT.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Natalie Paquette
DTSTART:20201215T150000Z
DTEND:20201215T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/17
DESCRIPTION:Title: Twisted holography & Koszul duality\nby Natalie Paquette
as part of CERN String Seminars\n\n\nAbstract\nIn this talk we discuss th
e problem of coupling quantum field theories to topological line defects a
nd explain that it is governed by a central mathematical notion called Kos
zul duality for associative algebras. We then propose an analogous physica
l definition of Koszul duality for chiral algebras. We will explain that i
n the context 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://stable.researchseminars.org/talk/CERNStringSem/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabrizio del Monte
DTSTART:20210112T130000Z
DTEND:20210112T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/18
DESCRIPTION:Title: BPS quivers of five-dimensional SCFTs\, Topological Strings
and q-Painlevé equations\nby Fabrizio del Monte as part of CERN Strin
g Seminars\n\n\nAbstract\nFive-dimensional SCFTs arise from M-theory compa
ctified on local (toric) Calabi-Yau threefolds. These theories are intrins
ically non-lagrangian\, although they often exhibit a low-energy gauge the
ory phase\, and their BPS states can be constructed as branes wrapping top
ologically nontrivial cycles in the Calabi-Yau geometry. In this talk I wi
ll show how to extract detailed information about the BPS sector of these
theories by the introduction of an associated graph\, called a quiver. The
quiver defines a discrete integrable system\, whose discrete time evoluti
on allows on the one hand to study the BPS particle spectrum of the theory
\, on the other hand to derive difference equations satisfied by its parti
tion function.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kantaro Ohmori
DTSTART:20210119T140000Z
DTEND:20210119T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/19
DESCRIPTION:Title: Categorical Symmetry in 1+1 dimensions\nby Kantaro Ohmor
i as part of CERN String Seminars\n\n\nAbstract\nGlobal symmetry plays a c
rucial role in the study of QFT. Recently\, various generalizations of the
concept of global symmetry has been proposed. In the talks I would like t
o discuss the notion called “categorical symmetry”\, or various other
names\, particularly in 1+1 dimensions. Such a “symmetry” lacks its in
verse\, and described by the mathematical concept of a fusion category\, i
nstead of a group. Physically it refers to the collection of all the topol
ogical line defects exists in the 2d QFT. A “categorical symmetry” is
preserved along an RG flow\, as an ordinary symmetry and its ’t Hooft an
omaly does\, which is crucial in its applications. It sometimes admits the
notion of “gauging”\, too.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Horacio Casini
DTSTART:20210126T130000Z
DTEND:20210126T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/20
DESCRIPTION:Title: Entropic order parameters for symmetries in QFT\nby Hora
cio Casini as part of CERN String Seminars\n\n\nAbstract\nIn QFT there is
an algebra of operators attached to any spacetime region. Simple degradati
ons of the most harmonious possible relation between algebras and regions
are shown to encode generalized symmetries. Nets of algebras with these sy
mmetries allow for a non uniqueness of the algebras that can be assigned t
o a given region. This non uniqueness suggests a simple geometrical order
parameter in terms of a relative entropy. These satisfy a ''certainty rela
tion'' connecting the statistics of the order and disorder parameters for
complementary regions. We describe how the lore about phases of theories w
ith generalized symmetries is seen in this new picture.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Ilesiu
DTSTART:20210216T150000Z
DTEND:20210216T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/21
DESCRIPTION:Title: The statistical mechanics of near-extremal and near-BPS blac
k holes\nby Luca Ilesiu as part of CERN String Seminars\n\n\nAbstract\
nAn important open question in black hole thermodynamics is about the exis
tence of a "mass gap" between an extremal black hole and the lightest near
-extremal state within a sector of fixed charge. In this talk\, I will dis
cuss how to reliably compute the partition function of 4d Reissner-Nordstr
om near-extremal black holes at temperature scales comparable to the conje
ctured gap. I will show that the density of states at fixed charge does no
t exhibit a gap in the simplest gravitational non-supersymmetric theories\
; rather\, at the expected gap energy scale\, we see a continuum of states
whose meaning we will extensively discuss. Finally\, I will present a sim
ilar computation for nearly-BPS black holes in 4d N=2 supergravity. As opp
osed to their non-supersymmetric counterparts\, such black holes do in fac
t exhibit a gap consistent with various string theory predictions.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony
DTSTART:20210223T130000Z
DTEND:20210223T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/22
DESCRIPTION:Title: A derivation of AdS/CFT for vector models\nby Ofer Aharo
ny as part of CERN String Seminars\n\n\nAbstract\nAfter discussing what it
means to derive the AdS/CFT correspondence\, I will describe our attempts
(in collaboration with Shai Chester and Erez Urbach\, 2011.06328) to make
this correspondence explicit in the simplest case of the U(N) vector mode
l. We explicitly 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 integr
al over fields (including massless high-spin fields) living on (d+1)-dimen
sional anti-de Sitter space. Inspired by de Mello Koch\, Jevicki\, Suzuki
and Yoon and earlier work\, we first rewrite the vector models in terms of
bi-local fields\, then expand these fields in eigenmodes of the conformal
group\, and finally map these eigenmodes to those of fields on anti-de Si
tter space. Our results provide an explicit (non-local) action for a high-
spin theory on anti-de Sitter space\, which is presumably equivalent in th
e large N limit to Vasiliev's classical high-spin gravity theory (with som
e specific gauge-fixing to a fixed background)\, but which can be used als
o for loop computations. Our mapping is explicit within the 1/N expansion\
, but in principle can be extended also to finite N theories\, where extra
constraints on products of bulk fields need to be taken into account.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Toldo
DTSTART:20210302T130000Z
DTEND:20210302T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/23
DESCRIPTION:Title: Rotating black holes in Anti-de Sitter and updates on the se
arch for 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 focus mainly on the gravitational part. After reviewing the known so
lutions\, I will describe how to construct two classes of stationary BPS c
onfigurations in theories of four-dimensional supergravity with uplift to
M-theory. In the second part of my talk I will discuss work in progress th
at investigates the existence of stable and metastable black hole bound st
ates at finite chemical potentials in global AdS spacetime\, in the probe
approximation. Time permitting\, I will finally discuss the relevance of t
hese setups for describing glassy systems via holography.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Guerrieri
DTSTART:20210309T130000Z
DTEND:20210309T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/24
DESCRIPTION:Title: Where is String Theory?\nby Andrea Guerrieri as part of
CERN String Seminars\n\n\nAbstract\nIn the last few years the S-matrix Boo
tstrap provided precise quantitative bounds on the low energy Wilson coeff
icients compatible with causality\, crossing symmetry and unitarity for so
me class of EFTs describing low energy QCD dynamics. In this talk I will d
iscuss the first application of this formalism to quantum gravity theories
. I will focus on the first non universal correction to the flat space sca
ttering amplitude of 10 dimensional supergravity particles\, and compare t
he results with the String Theory predictions.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aninda Sinha
DTSTART:20210316T130000Z
DTEND:20210316T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/25
DESCRIPTION:Title: Quantum field theory and the Bieberbach conjecture\nby A
ninda Sinha as part of CERN String Seminars\n\n\nAbstract\nI will discuss
an intriguing correspondence between ingredients in geometric function the
ory related to the famous Bieberbach conjecture (de Branges' theorem) and
the non-perturbative crossing symmetric representation of 2-2 scattering a
mplitudes of identical scalars. I will point out two sided bounds on the a
mplitude as well as on certain Wilson coefficients that arise from this co
rrespondence.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yifan Wang
DTSTART:20210323T143000Z
DTEND:20210323T163000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/26
DESCRIPTION:Title: Defects and Anomalies in Quantum Field Theories\nby Yifa
n Wang as part of CERN String Seminars\n\n\nAbstract\nI will review some r
ecent developments in understanding the structure of anomalies in the pres
ence of defects in CFTs. The defect insertions lead to new 't Hooft anomal
ies and conformal anomalies on the defect worldvolume. The latter give ris
e to defect analogs of the c-theorem (a-theorem) which establish the monot
onicity of defect RG flows. With supersymmetry\, the defect conformal anom
alies are related to the 't Hooft anomalies for certain U(1) R-symmetry in
a simple way\, and can be determined non-perturbatively from an algebraic
procedure. In the talk I'll mostly focus on surface defects to be concret
e and comment on extensions and future directions towards the end.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sakura Schafer-Nameki
DTSTART:20210330T120000Z
DTEND:20210330T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/27
DESCRIPTION:Title: Higher Form symmetries in String Theory and Applications to
Confinement\nby Sakura Schafer-Nameki as part of CERN String Seminars\
n\n\nAbstract\nI will give an overview of recent developments in higher fo
rm symmetries in string theory\, in particular in geometric constructions
of QFTs. As an application I will discuss setups in string theory realizin
g confining vacua in the light of their 1-form symmetries.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Subham Dutta Chowdhury
DTSTART:20210406T120000Z
DTEND:20210406T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/28
DESCRIPTION:Title: Bounds on Regge growth of flat space scattering from bounds
on chaos\nby Subham Dutta Chowdhury as part of CERN String Seminars\n\
n\nAbstract\nWe study four-point functions of scalars\, conserved currents
\, and stress tensors in a conformal field theory\, generated by a local c
ontact term in the bulk dual description\, in two different causal configu
rations. The first of these is the standard Regge configuration in which t
he chaos bound applies. The second is the `causally scattering configurati
on' in which the correlator develops a bulk point singularity. We find an
expression for the coefficient of the bulk point singularity in terms of t
he 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 sc
attering sheet in terms of the Regge growth of this S matrix. We then demo
nstrate 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 cha
os bound\, which turns out to be violated unless the bulk flat space S mat
rix grows no faster than s^2 in the Regge limit. It follows that in the co
ntext of the AdS/CFT correspondence\, the chaos bound applied to the bound
ary field theory implies that the S matrices of the dual bulk scalars\, ga
uge fields\, and gravitons obey the Classical Regge Growth (CRG) conjectur
e.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dalimil Mazac
DTSTART:20210413T130000Z
DTEND:20210413T150000Z
DTSTAMP:20260404T093135Z
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
bounding higher derivative couplings in consistent weakly coupled gravitat
ional theories. The starting point will be general assumptions about analy
ticity and Regge growth of the S-matrix. Higher derivative couplings are e
xpected to be of order one in the units of the UV cutoff. Our approach jus
tifies this expectation and allows us to prove precise bounds on the order
one coefficients. I will explain that the notorious difficulties presente
d by the graviton pole can be overcome by measuring couplings at small imp
act parameter\, rather than in the forward limit. I will illustrate the me
thod in theories containing a massless scalar coupled to gravity\, and in
theories with maximal supersymmetry.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ben Freivogel
DTSTART:20210420T120000Z
DTEND:20210420T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/30
DESCRIPTION:Title: Wormholes from averaging over states\nby Ben Freivogel a
s part of CERN String Seminars\n\n\nAbstract\nI will show that wormholes n
aturally arise as the gravity dual of an average over different states wit
hin a single conformal field theory. These wormholes give a simple way to
diagnose how typical pure states differ from the thermal density matrix.
Based on work to appear with D. Nikolakopoulou and A. Rotundo.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Julio Parra Martinez
DTSTART:20210427T140000Z
DTEND:20210427T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/31
DESCRIPTION:Title: Collider tools for classical gravity\nby Julio Parra Mar
tinez as part of CERN String Seminars\n\n\nAbstract\nI will describe recen
t progress in the program to apply tools originally developed for computin
g cross sections in colliders to problems in classical general relativity.
This effort has recently produced state-of-the-art computations of quanti
ties relevant for current and future gravitational wave detectors\, such a
s the conservative two-body Hamiltonian at the fourth order in Newton’s
constant\, G^4\, as well as the G^3 radiated energy in binary black hole e
ncounters and elliptical orbits. I will explain how these calculations wer
e made possible by leveraging on-shell techniques\, effective field theory
\, modern loop integration machinery and an improved understanding of the
connection between classical scattering amplitudes and the semiclassical o
n-shell action.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Pate
DTSTART:20210504T130000Z
DTEND:20210504T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/32
DESCRIPTION:Title: Flatspace Holography: Celestial Amplitudes and Symmetries\nby Monica Pate as part of CERN String Seminars\n\n\nAbstract\nThe ident
ification of quantum field theoretic soft theorems with constraints from i
nfinite-dimensional asymptotic symmetries offers exciting prospects for th
e development of flatspace holography. In four spacetime dimensions\, the
asymptotic symmetry group includes the local conformal (Virasoro) symmetry
of two dimensions\, motivating the proposal that 4D scattering is hologra
phically dual to a 2D conformal theory. Lorentz symmetry in four dimension
s comprises the global part of the 2D conformal group of the dual. Cele
stial amplitudes which capture the scattering of particles in boost as opp
osed to momentum eigenstates transform like correlation functions of prima
ry operators under 4D Lorentz transformations. I will describe how celes
tial amplitudes admit a variety of other properties -- including an operat
or product expansion and rich symmetry algebra -- which are indicative of
an underlying two-dimensional holographic dual theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steve Shenker
DTSTART:20210511T150000Z
DTEND:20210511T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/33
DESCRIPTION:Title: Wormholes without averaging\nby Steve Shenker as part of
CERN String Seminars\n\n\nAbstract\nAfter averaging over fermion coupling
s\, SYK has a collective field description that sometimes has “wormhole
” solutions. We study the fate of these wormholes when the couplings are
fixed. Working mainly in a simple model\, we find that the wormhole saddl
es persist\, but that new saddles also appear elsewhere in the integration
space – “half-wormholes.” The wormhole contributions depend only we
akly on the specific choice of couplings\, while the half-wormhole contrib
utions are strongly sensitive. The half-wormholes are crucial for factoriz
ation of decoupled systems with fixed couplings\, but they vanish after av
eraging\, leaving the non-factorizing wormhole behind. (Joint work with
Phil Saad\, Douglas Stanford and Shunyu Yao.)\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello
DTSTART:20210518T140000Z
DTEND:20210518T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/34
DESCRIPTION:Title: Four-dimensional integrability and twistors\nby Kevin Co
stello as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Kolchmeyer
DTSTART:20210525T120000Z
DTEND:20210525T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/35
DESCRIPTION:Title: Dynamical End-of-the-world Branes in Jackiw-Teitelboim Gravi
ty\nby David Kolchmeyer as part of CERN String Seminars\n\n\nAbstract\
nJackiw-Teitelboim gravity with end-of-the-world (EoW) branes has been use
d to study the black hole information problem. In this talk\, I consider d
ynamical EoW branes by summing over loops of branes in the Euclidean path
integral. The UV divergences that arise are treated in the context of effe
ctive field theory. The EoW branes make a contribution to the black hole e
ntropy that is consistent with a state-counting interpretation of the entr
opy. I will also discuss how the effective field theory logic is mirrored
in the dual matrix model.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Suvrat Raju
DTSTART:20210928T120000Z
DTEND:20210928T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/36
DESCRIPTION:Title: Holography of Information and Massive Islands\nby Suvrat
Raju as part of CERN String Seminars\n\n\nAbstract\nWe will review recent
results that suggest that\, in any standard theory of quantum gravity\, i
nformation available on the bulk of a Cauchy slice must also be available
near the boundary of the slice. These ideas indicate how holography sho
uld be extended to four dimensional asymptotically flat spacetimes but the
y also shed light on the origins of AdS/CFT. We contrast this picture with
the paradigm of islands and argue that islands are consistent only in the
ories of 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/2107.0
3390 \n3) "Lessons from the Information Paradox" (review)\nhttps://arxiv.o
rg/abs/2012.05770\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ashoke Sen
DTSTART:20211005T120000Z
DTEND:20211005T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/37
DESCRIPTION:Title: D-instanton amplitudes in string theory\nby Ashoke Sen a
s part of CERN String Seminars\n\n\nAbstract\nI shall review the problems
in computing D-instanton\ncontribution to string amplitudes using the usua
l world-sheet methods\, and\nrecent progress in overcoming these difficult
ies using insights from\nstring field theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dierigl\, Markus
DTSTART:20211012T120000Z
DTEND:20211012T140000Z
DTSTAMP:20260404T093135Z
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
possible quantum anomalies in the duality group of type IIB string theory
. Quite surprisingly\, these do not vanish\, which would signal an inconsi
stency of F-theory. A subtle modification of the type IIB Chern-Simons ter
m cancels the anomalies in a highly non-trivial way. However\, in principl
e there are alternative ways to cancel the anomaly which might point towar
ds the existence of a discrete string theory landscape.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pietro Ferrero
DTSTART:20211019T120000Z
DTEND:20211019T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/39
DESCRIPTION:Title: Gluon scattering in AdS from CFT\nby Pietro Ferrero as p
art of CERN String Seminars\n\n\nAbstract\nI will present a class of recen
tly computed holographic correlators between half-BPS operators in a vast
array of SCFTs with non-maximal superconformal symmetry in dimensions d=3\
,4\,5\,6. Via AdS/CFT\, these four-point functions are dual to gluon scatt
ering amplitudes in AdS. Exploiting the notion of MRV limit I will show th
at\, at tree level\, all such correlators are completely fixed by symmetri
es and consistency conditions. Our results encode a wealth of novel CFT da
ta and exhibit various emergent structures\, including Parisi-Sourlas supe
rsymmetry\, hidden conformal symmetry and color-kinematics duality.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cyril Closset
DTSTART:20211026T120000Z
DTEND:20211026T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/40
DESCRIPTION:Title: The U-plane of rank-one 4d N=2 KK theories\nby Cyril Clo
sset as part of CERN String Seminars\n\n\nAbstract\nI will revisit the Sei
berg-Witten description of the Coulomb branch of rank-one 4d N=2 supersymm
etric QFTs\, including aspects of the global symmetry\, from the point of
view of rational elliptic surfaces. This will include\, in particular\, a
detailed study of the 5d superconformal field theories with E_n symmetry\,
compactified on a circle. I will also sketch how to derive BPS quivers fr
om that perspective. Interesting modular properties of the SW geometries w
ill play a key role.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Faulkner
DTSTART:20211102T140000Z
DTEND:20211102T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/41
DESCRIPTION:Title: Reflected Entropy for Holography and Beyond\nby Tom Faul
kner as part of CERN String Seminars\n\n\nAbstract\nI will discuss a new q
uantum information measure\, called reflected entropy\, that was originall
y discovered in holography. Reflected entropy goes beyond entanglement ent
ropy in its ability to constrain the patterns of entanglement and in holog
raphic theories allows one to move beyond probing minimal surfaces in the
emergent bulk. I will then discuss more recent results on studying this qu
antity in random tensor networks where similar dualities are discovered.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Clifford Johnson
DTSTART:20211109T130000Z
DTEND:20211109T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/42
DESCRIPTION:Title: The Microstate Physics of JT gravity and Supergravity\nb
y Clifford Johnson as part of CERN String Seminars\n\n\nAbstract\nMany key
physical phenomena in JT gravity are only accessible if one goes beyond t
he topological expansion to capture non-perturbative effects. This can be
done explicitly using random matrix models\, if formulated in such a way a
s to extract non-perturbative physics. Such a framework\, developed previo
usly for JT by the Author\, is briefly reviewed in this talk. Then a new t
ool is added: a particular Fredholm determinant. It allows for a surprisin
gly thorough excavation of the detailed microstate spectrum of a non-pertu
rbative completion of JT gravity and several super JT variants. This then
allows for the full quenched Free Energy to be computed for these models f
or the first time\, completing the low temperature thermodynamics. Possibl
e implications for the spectrum of higher dimensional near extremal black
holes are suggested.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Puhm
DTSTART:20211116T130000Z
DTEND:20211116T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/43
DESCRIPTION:Title: Towards flat space holography via diamonds on the celestial
sphere\nby Andrea Puhm as part of CERN String Seminars\n\n\nAbstract\n
The basic observable of quantum gravity in asymptotically flat spacetimes
is the S-matrix. When recast in a basis of boost eigenstates scattering am
plitudes transform as conformal correlators of primary operators in the du
al ''celestial CFT''. This observation together with novel insights about
the infrared aspects of gauge theory and gravity have reinvigorated attemp
ts at a holographic principle for flat space. Essential to building a holo
graphic dictionary is to understand the spectrum and the symmetries of the
dual theory. I will describe recent progress in this direction. A natural
language for describing the (conformally) soft sector of scattering is vi
a celestial diamonds which encode the structure of global conformal multip
lets and\, upon adding supersymmetry\, stack into a pyramid. They unify th
e discussion of QFT soft theorems\, (asymptotic) symmetry generators and G
oldstone modes appearing in conformal dressings. Combining these ingredien
ts I will end with some speculations on effective descriptions for the con
formally soft sector of celestial CFT which captures the spontaneous (asym
ptotic) symmetry breaking dynamics.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter
DTSTART:20211130T130000Z
DTEND:20211130T150000Z
DTSTAMP:20260404T093135Z
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-Mills obeys S-duality. A new way to process this symmetry leads to st
rong consequences for the CFT data and for the nature of holographic duali
ty. Based on work with Scott Collier.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Nega
DTSTART:20211207T130000Z
DTEND:20211207T150000Z
DTSTAMP:20260404T093135Z
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\
nAbstract\nIn this talk I will explain the relation between Calabi-Yau man
ifolds and their mathematics and Feynman integral computations. We will se
e how concepts from Calabi-Yau geometries and especially Calabi-Yau motive
s can be used to compute multi-loop Feynman integrals. This will be exempl
ified with the so called banana graphs. First\, I will give a short introd
uction to Feynman integrals and Calabi-Yau manifolds. Then we will see how
the mathematics of Calabi-Yau manifolds (variations of Hodge structures\,
Griffiths transversality\, \nΓ-class\, ...) constrain or even determine
the corresponding Feynman integrals\, here the banana graphs. Then I will
also shortly explain how the banana integrals can be solved in dimensional
regularization in the equal- as well as in the generic-mass case. Finally
\, I will make some remarks what we can in general learn from Calabi-Yau s
paces in the context of Feynman integrals.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Beatrix Muehlmann
DTSTART:20211214T130000Z
DTEND:20211214T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/46
DESCRIPTION:Title: The semiclassical gravitational path integral and random mat
rices\nby Beatrix Muehlmann as part of CERN String Seminars\n\n\nAbstr
act\nIn this talk I will discuss the genus expansion over compact Riemann
surfaces of the semiclassical gravitational path integral in two spacetime
dimensions coupled to one of the minimal models (2\,2m-1). In the semicla
ssical limit we take m to infinity. Conjecturally this path integral allow
s for a completion in terms of an integral over large random Hermitian mat
rices\, known as a multicritical matrix integral. I will discuss the genus
expansion of multicritical matrix integrals and relate invariant quantiti
es stemming both from matrix as well as gravity calculations. Inspired by
the proposal of Gibbons and Hawking relating the de Sitter entropy to a gr
avitational path integral\, this setup paves a possible path toward a micr
oscopic picture of a two-dimensional de Sitter universe.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Hartman
DTSTART:20211221T130000Z
DTEND:20211221T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/47
DESCRIPTION:Title: Talk by Tom Hartman\nby Tom Hartman as part of CERN Stri
ng Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jens Eisert
DTSTART:20220111T130000Z
DTEND:20220111T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/48
DESCRIPTION:Title: Linear growth of quantum circuit complexity\nby Jens Eis
ert as part of CERN String Seminars\n\n\nAbstract\nQuantifying quantum sta
tes' complexity is a key problem in various subfields of science\, from qu
antum computing to black-hole physics. In this talk\, we prove a prominent
conjecture by Brown and Susskind about how random quantum circuits' compl
exity increases [1]. Consider constructing a unitary from Haar-random two-
qubit quantum gates. Implementing the unitary exactly requires a circuit o
f some minimal number of gates - the unitary's exact circuit complexity. W
e 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 lower-bounding the exact circuit complexity. Our strategy combines dif
ferential topology and elementary algebraic geometry with an inductive con
struction of Clifford circuits. We have a brief look at the role entanglem
ent plays here [2]. In a long outlook\, we will have a look at what could
be called a resource theory of quantum uncomplexity [3].\n\n[1] J. Haferka
mp\, P. Faist\, N. B. T. Kothakonda\, J. Eisert\, N. Yunger Halpern\, Line
ar growth of quantum circuit complexity\, arXiv:2106.05305\, Nature Physic
s\, in press (2022).\n[2] J. Eisert\, Entangling power and quantum circuit
complexity\, arXiv:2104.03332\, Physical Review Letters 127\, 020501 (202
1).\n[3] N. Yunger Halpern\, N. B. T. Kothakonda\, J. Haferkamp\, A. Munso
n\, J. Eisert\, P. Faist\, Resource theory of quantum uncomplexity\, arXiv
:2110.11371 (2021).\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/48/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Nardoni
DTSTART:20220118T100000Z
DTEND:20220118T120000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/49
DESCRIPTION:Title: From Seiberg-Witten Theory to Adjoint QCD\nby Emily Nard
oni as part of CERN String Seminars\n\n\nAbstract\nStandard lore suggests
that four-dimensional SU(N) gauge theory with 2 massless adjoint Weyl ferm
ions ("adjoint QCD") flows to a phase with confinement and chiral symmetry
breaking. In this talk\, we will test and present new evidence for this l
ore. Our strategy involves realizing adjoint QCD in the deep IR of a renor
malization group flow descending from SU(N) Seiberg-Witten theory\, deform
ed by a soft supersymmetry-breaking mass for its adjoint scalars. A crucia
l role in the analysis is played by a dual Lagrangian that originates from
the multi-monopole points of Seiberg-Witten theory\, and which can be use
d to explore 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 f
irst-order transitions\, that interpolate between the Coulomb phase of Sei
berg-Witten theory and the confining\, chiral symmetry breaking phase expe
cted for adjoint QCD.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Javier Magan
DTSTART:20220125T130000Z
DTEND:20220125T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/50
DESCRIPTION:Title: A new look at completeness and generalized symmetries\nb
y Javier Magan as part of CERN String Seminars\n\n\nAbstract\nWe describe
a general principle of completeness in QFT. It asserts that the physical o
bservable algebras produced by local degrees of freedom are the maximal on
es compatible with causality. We elaborate on equivalent statements to thi
s principle such as the non-existence of generalized symmetries and the un
iqueness of the net of algebras. For non-complete theories\, we explain ho
w the existence of generalized symmetries is unavoidable\, and further\, t
hat they always come in dual pairs with precisely the same "size"\, measur
ed by the Jones or algebraic index. Entropic order/disorder parameters can
be defined that sense the dual pairs of generalized symmetries and satisf
y a relation dubbed the certainty principle\, due to its connection with t
he uncertainty principle in quantum mechanics. Using this new understandin
g we prove a recent conjecture by Harlow and Ooguri concerning a universal
formula for the charged density of states in QFT\, comment on relations w
ith the Weinberg-Witten theorem\, and argue against the existence of gener
alized symmetries in the bulk of holographic theories.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Justin Kaidi
DTSTART:20220201T150000Z
DTEND:20220201T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/51
DESCRIPTION:Title: Kramers-Wannier-like duality defects in (3+1)d gauge theorie
s\nby Justin Kaidi as part of CERN String Seminars\n\n\nAbstract\nI wi
ll introduce a class of non-invertible topological defects in (3+1)d gauge
theories whose fusion rules are the higher-dimensional analogs of those o
f the Kramers-Wannier defect in the (1+1)d critical Ising model. As in the
lower-dimensional case\, the presence of such non-invertible defects impl
ies self-duality under a particular gauging of the discrete (higher-form)
symmetries. I will illustrate this by means of the example of SO(3) Yang-M
ills (YM) at θ=π\, as well as SU(2)N=4 SYM at τ=i.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Sharpe
DTSTART:20220208T130000Z
DTEND:20220208T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/52
DESCRIPTION:Title: An introduction to decomposition\nby Eric Sharpe as part
of CERN String Seminars\n\n\nAbstract\nIn this talk I will review work on
'decomposition\,' a property of 2d theories with 1-form symmetries and\,
more generally\, d-dim'l theories with (d-1)-form symmetries. Decompositio
n is the observation that such quantum field theories are equivalent to ('
decompose into’) disjoint unions of other QFTs\, known in this context a
s "universes.”\n\nExamples include two-dimensional gauge theories and or
bifolds with matter invariant under a subgroup of the gauge group. Decompo
sition explains and relates several physical properties of these theories
-- for example\, restrictions on allowed instantons arise as a "multiverse
interference effect" between contributions from constituent universes.\n\
nFirst worked out in 2006 as part of efforts to understand string propagat
ion on stacks\, decomposition has been the driver of a number of developme
nts since. In the first half of this talk\, I will review decomposition\;
in the second half\, I will focus on the recent application to anomaly res
olution of Wang-Wen-Witten in two-dimensional orbifolds.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou
DTSTART:20220215T160000Z
DTEND:20220215T173000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/53
DESCRIPTION:Title: Falling inside holographic black holes\nby Lampros Lampr
ou as part of CERN String Seminars\n\n\nAbstract\nI will present a bulk re
construction technique in AdS/CFT suitable for addressing a facet of the b
lack hole information problem: how to unambiguously predict the results of
measurements accessible to an infalling observer in the black hole interi
or. I will explicitly apply the method in the AdS_2/SYK correspondence and
comment on its generalizations.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elli Pomoni
DTSTART:20220222T130000Z
DTEND:20220222T150000Z
DTSTAMP:20260404T093135Z
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 revisi
t the study of spin chains capturing the spectral problem of 4d N = 2 SCFT
s in the planar limit. At one loop and in the quantum plane limit\, we wil
l discover a quasi-Hopf symmetry algebra\, defined by the R-matrix read of
f from the superpotential. This implies that when orbifolding the N = 4 sy
mmetry algebra down to the N = 2 one and then marginaly deforming\, the br
oken generators are not lost\, but get upgraded to quantum generators. The
reafter\, we will demonstrate that these chains are dynamical\, in the sen
se that their Hamiltonian depends on a parameter which is dynamically dete
rmined along the chain. At one loop we will show how to map the holomorphi
c SU(3) scalar sector to a dynamical 15-vertex model\, which corresponds t
o an RSOS model\, whose adjacency graph can be read off from the gauge the
ory quiver/brane tiling. One scalar SU(2) sub-sector is described by an al
ternating nearest-neighbour Hamiltonian\, while another choice of SU(2) su
b-sector leads to a dynamical dilute Temperley-Lieb model. These sectors h
ave a common vacuum state\, around which the magnon dispersion relations a
re naturally 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- and two-magnon problems with the coordinate Bethe ansatz approach.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shamit Kachru
DTSTART:20220301T163000Z
DTEND:20220301T183000Z
DTSTAMP:20260404T093135Z
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 focus on the role of foliated field theories and field theories with ex
otic symmetry in their construction. I then turn to the realization\n— o
n systems of branes in string theory\n— of several novel theories of thi
s sort.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scott Collier
DTSTART:20220308T150000Z
DTEND:20220308T170000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/56
DESCRIPTION:Title: Bootstrapping boundaries and branes\nby Scott Collier as
part of CERN String Seminars\n\n\nAbstract\nI will describe recent work w
ith Dalimil Mazac and Yifan Wang initiating the systematic bootstrap study
of conformal boundary conditions in 2d CFTs by investigation of the boots
trap equation that arises from the open-closed consistency condition of th
e annulus partition function with identical boundaries. We find that this
deceivingly simple bootstrap equation\, when combined with unitarity\, lea
ds to surprisingly strong constraints on admissible boundary states. In pa
rticular\, we derive universal bounds on the tension (boundary entropy) of
stable boundary conditions\, which provide a rigorous diagnostic for pote
ntial D-brane decays. We also find unique solutions to the bootstrap probl
em of stable branes in a number of rational CFTs. Along the way\, we obser
ve a curious connection between the annulus bootstrap and the sphere packi
ng problem\, which is a natural extension of previous work on the modular
bootstrap. We also derive bounds on the boundary entropy at large central
charge. These potentially have implications for end-of-the-world branes in
pure gravity on AdS_3.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Heckman
DTSTART:20220315T130000Z
DTEND:20220315T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/57
DESCRIPTION:Title: Top Down Approach to Ensemble Averaging\nby Jonathan Hec
kman 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 rec
ent interest in the context of the AdS/CFT correspondence. In this talk we
present a stringy realization of quantum field theory ensembles in D ≤
4 spacetime dimensions. This provides a UV completion of a recent proposal
of Marolf and Maxfield that there is a high-dimensional Hilbert space for
baby universes\, but one that is compatible with the proposed Swampland c
onstraints of McNamara and Vafa. We identify two ways in which our constru
ction breaks down\, one of which is sensitive to short distance effects\,
and one which is an entropic effect for objects with a large number of mic
rostates. The construction thus provides an explicit set of counterexample
s to the claim that holography can be fully decoupled from top down consid
erations.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/57/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paweł Caputa
DTSTART:20220322T130000Z
DTEND:20220322T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/58
DESCRIPTION:Title: Krylov complexity for operators and states\nby Paweł Ca
puta as part of CERN String Seminars\n\n\nAbstract\nI will discuss a recen
t notion of complexity in quantum systems called Krylov complexity. After
defining it for operators as well as for states\, I will present some resu
lts which test this interesting new probe in different many-body systems.
This talk will be based on arXiv: 2109.03824\, 2110.10519 and 2202.06957.\
n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/58/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomasevic
DTSTART:20220329T120000Z
DTEND:20220329T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/59
DESCRIPTION:Title: Black tsunamis and naked singularities in AdS\nby Marija
Tomasevic as part of CERN String Seminars\n\n\nAbstract\nWe study the evo
lution of the Gregory-Laflamme instability for black strings in global AdS
spacetime\, and investigate the CFT dual of the formation of a bulk naked
singularity. 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 horiz
on generators from the asymptotic boundary (a `black tsunami')\; a pinch-o
ff of the horizon that likely reveals a naked singularity\; and competitio
n between these two behaviours\, such as a nakedly singular pinch-off that
subsequently gets covered by a black tsunami. The holographic dual descri
bes different patterns of heat flow due to the Hawking radiation of two bl
ack holes placed at the antipodes of a spherical universe. We also present
a model that describes\, in any D\, the burst in the holographic stress-e
nergy tensor when the signal from a bulk self-similar naked singularity re
aches the boundary. The model shows that the shear components of the bound
ary stress diverge in finite time\, while the energy density and pressures
from the burst vanish.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/59/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gustavo Joaquin Turiaci
DTSTART:20220405T140000Z
DTEND:20220405T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/60
DESCRIPTION:Title: Nearly BPS black holes and the spectrum of N=4 Yang Mills\nby Gustavo Joaquin Turiaci as part of CERN String Seminars\n\n\nAbstrac
t\nWe will discuss quantum corrections in the gravitational path integral
around nearly 1/16-BPS black holes in asymptotically AdS5 x S5 space\, dua
l to heavy operators in N=4 SYM. These quantum corrections come from a ver
sion 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 poten
tial. Using this approach\, holography predicts the presence of a gap betw
een the BPS black holes and the lightest near-BPS black holes\, and the sp
ectrum of near-BPS states that lie above this gap. We will also discuss st
ringy and non-perturbative corrections that can affect the black hole spec
trum.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/60/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Manus Visser
DTSTART:20220412T120000Z
DTEND:20220412T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/61
DESCRIPTION:Title: De Sitter Entropy and the Gravitational Path Integral\nb
y Manus Visser as part of CERN String Seminars\n\n\nAbstract\nGibbons and
Hawking famously derived the de Sitter horizon entropy from the Euclidean
gravitational path integral in the saddle point approximation. In this tal
k we extend this result in two different ways. First\, we compute the entr
opy of de Sitter black holes from the on-shell Euclidean action\, and take
their contributions in the gravitational path integral into account using
the formalism of constrained instantons. We use this to calculate the pai
r creation rate of arbitrary mass black holes in de Sitter space. Second\,
in two-dimensional de Sitter space we show how the generalized entropy ca
n be obtained from an on-shell action for semiclassical dilaton gravity in
the microcanonical ensemble. Minimizing the action yields extremizing the
generalized entropy\, consistent with the island formula.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/61/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorrit Kruthoff
DTSTART:20220419T143000Z
DTEND:20220419T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/62
DESCRIPTION:Title: Higher spin JT gravity and a matrix model dual\nby Jorri
t Kruthoff as part of CERN String Seminars\n\n\nAbstract\nIn this talk I w
ill propose and discuss a generalization of the Saad-Shenker-Stanford dual
ity between matrix models and JT gravity to the case in which the bulk inc
ludes higher spin fields. Using an PSL(N\,R) BF theory we compute the disk
and generalization of the trumpet partition function in this theory. Usin
g an appropriate subspace of the moduli space of flat PSL(N\,R) connection
s on a Riemann surface Σ we propose a recipe for computing the cylinder c
ontribution. This gives a 𝑇𝑁−1 behaviour at late times 𝑇\, sign
aling a deviation from conventional random matrix theory. To account for t
his deviation\, we propose that the bulk theory is dual to a matrix model
consisting of N-1 commuting matrices associated to the N-1 conserved charg
es in the boundary theory. Due to its modified eigenvalue repulsion\, the
spectral two-point function reproduces the late time gravitational answer.
\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/62/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claire Zukowski
DTSTART:20220503T120000Z
DTEND:20220503T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/63
DESCRIPTION:Title: Virasoro Entanglement Berry Phases\nby Claire Zukowski a
s part of CERN String Seminars\n\n\nAbstract\nI will describe the parallel
transport of modular Hamiltonians encoding entanglement properties of a s
tate. The Berry curvature associated to state-changing parallel transport
is the Kirillov-Kostant symplectic form on an associated coadjoint orbit\,
one which differs appreciably from known Virasoro orbits. I will show tha
t the boundary parallel transport process computes a bulk symplectic form
for a Euclidean geometry obtained from the backreaction of a cosmic brane\
, with Dirichlet boundary conditions at the location of the brane. This co
nstruction gives a definition for the symplectic form on an entanglement w
edge.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/63/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dan Roberts
DTSTART:20220510T120000Z
DTEND:20220510T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/64
DESCRIPTION:Title: The Principles of Deep Learning Theory\nby Dan Roberts a
s part of CERN String Seminars\n\n\nAbstract\nDeep learning is an exciting
approach to modern artificial intelligence based on artificial neural net
works. The goal of this talk is to provide a blueprint — using tools fro
m physics — for theoretically analyzing deep neural networks of practica
l relevance. This task will encompass both understanding the statistics of
initialized deep networks and determining the training dynamics of such a
n ensemble when learning from data. Borrowing from the "effective theory"
framework of physics and developing a perturbative 1/n expansion around th
e limit of infinite hidden-layer width\, we will find a principle of spars
ity that will let us describe effectively-deep networks of practical large
-but-finite-width networks.\n\nThis talk is based on a book\, "The Princip
les of Deep Learning Theory\," co-authored with Sho Yaida and based on res
earch also in collaboration with Boris Hanin. It will be published this mo
nth by Cambridge University Press.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/64/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pronobesh Maity
DTSTART:20220517T120000Z
DTEND:20220517T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/65
DESCRIPTION:Title: From Fields to Strings\nby Pronobesh Maity as part of CE
RN String Seminars\n\n\nAbstract\nI will describe a mechanism to reorganiz
e the Feynman diagrams of a perturbative large N gauge theory into localiz
ed integrals over closed string moduli space using the Strebel parametriza
tion of the latter. This will be explicitly illustrated for free symmetric
product orbifold CFTs where holomorphic covering maps play a key role. Af
ter recasting these covering maps in terms of dual worldsheet twistor fiel
ds in 𝐴𝑑𝑆3\, it will be generalized for 𝐴𝑑𝑆5. Imposing
appropriate reality conditions\, I will discuss a proposed stringy inciden
ce relation. 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 th
ese maps\, reproduces the Feynman propagator.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/65/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Valentin Benedetti
DTSTART:20220628T120000Z
DTEND:20220628T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/67
DESCRIPTION:Title: Generalized symmetries and Noether's theorem in QFT\nby
Valentin Benedetti as part of CERN String Seminars\n\n\nAbstract\nWe show
that generalized symmetries cannot be charged under a continuous global sy
mmetry having a Noether current. Further\, only non-compact generalized sy
mmetries 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 u
se these results to rederive Weinberg-Witten’s theorem within local QFT\
, generalizing it to massless particles in arbitrary dimensions and repres
entations of the Lorentz group. We end up discussing the conditions for th
e existence of a Noether current\, dynamical aspects of QFT’s with non-c
ompact generalized symmetries\, scale vs conformal invariance and the Cole
man-Mandula theorem.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/67/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohsen Alishahiha
DTSTART:20220811T120000Z
DTEND:20220811T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/68
DESCRIPTION:Title: On Complexity Saturation for JT gravity with EOW brane\n
by Mohsen Alishahiha as part of CERN String Seminars\n\n\nAbstract\nWe con
sider the complexity of a single-sided AdS black hole as modelled by an en
d-of-the-world brane. We compute the complexity using a modified replica t
rick corresponding to the "quenched geodesic length" in JT gravity. The la
te 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 complex
ity\, namely it being time-independent at late times.\n\nPlease note that
there will be no Zoom connection\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/68/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Diego Rodriguez-Gomez
DTSTART:20220809T120000Z
DTEND:20220809T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/69
DESCRIPTION:Title: Field theory defects through double scaling limits\nby D
iego Rodriguez-Gomez as part of CERN String Seminars\n\n\nAbstract\nDefect
operators in field theory are very interesting for a number of reasons. D
rawing inspiration from techniques which have been very recently applied t
o uncover interesting properties of sectors of operators with large charge
under a global symmetry\, we will study simple defects in the Wilson-Fish
er fixed point near d=4\,6 dimensions. Combining with localization\, we wi
ll also introduce a double-scaling limit for certain Wilson loops in N=2 s
upersymmetric theories in 4d which allows to make exact statements at fini
te N.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/69/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Silva
DTSTART:20220819T090000Z
DTEND:20220819T100000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/70
DESCRIPTION:Title: AdS Virasoro-Shapiro from dispersive sum rules\nby Joao
Silva as part of CERN String Seminars\n\n\nAbstract\nWe consider the four-
point correlator of the stress-energy tensor in N=4 SYM\, to leading order
in inverse powers of the central charge\, but including all order correct
ions in 1/lambda. This corresponds to the AdS version of the Virasoro-Shap
iro amplitude to all orders in the small alpha'/low energy expansion. Usin
g dispersion relations in Mellin space\, we derive an infinite set of sum
rules. These sum rules strongly constrain the form of the amplitude\, and
determine all coefficients in the low energy expansion in terms of the CFT
data for heavy string operators\, in principle available from integrabili
ty. For the first set of corrections to the flat space amplitude we find a
unique solution consistent with the results from integrability and locali
sation.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/70/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elias Kiritsis
DTSTART:20220829T120000Z
DTEND:20220829T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/71
DESCRIPTION:Title: Holographic QFTs on AdS\, wormholes and interfaces\nby E
lias Kiritsis as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/71/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Avia Raviv-Moshe
DTSTART:20220906T130000Z
DTEND:20220906T150000Z
DTSTAMP:20260404T093135Z
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 talk\, we will consider line defects (one-dimensional defects) in CFT
s. Such systems are of relevance to various physical systems\, with applic
ations 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 be
en achieved. Then\, we will focus on two types of applications: models of
spin impurities and Wilson lines in conformal gauge theories.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/72/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Massimo Porrati
DTSTART:20220909T120000Z
DTEND:20220909T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/73
DESCRIPTION:Title: Partition Functions of Abelian Chern-Simons Theories on Hand
lebodies Partition Functions of Abelian Chern-Simons Theories on Handlebod
ies\nby Massimo Porrati as part of CERN String Seminars\n\n\nAbstract\
nThis talk reviews the use of radial quantization to compute Chern-Simons
partition functions on handlebodies of arbitrary genus. The partition func
tion is given by a particular transition amplitude between two states whic
h are defined 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 insertion
s\, we find that the Wilson loop shifts the holonomy of the initial state.
Together with an appropriate choice of normalization\, this procedure sel
ects a unique state in the Hilbert space obtained from a Kähler quantizat
ion of the theory on the constant-radius Riemann surfaces. Radial quantiza
tion allows us to find the partition functions of Abelian Chern-Simons the
ories for handlebodies of arbitrary genus. For non-Abelian compact gauge g
roups\, we show that our method reproduces the known partition function an
d Wilson loop VEVs at genus one.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/73/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shreya Vardhan
DTSTART:20220920T120000Z
DTEND:20220920T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/74
DESCRIPTION:Title: Non-isometric codes and effective field theory in the black
hole interior\nby Shreya Vardhan as part of CERN String Seminars\n\n\n
Abstract\nI will argue that recent derivations of the Page curve for evapo
rating black holes using the quantum extremal surface formula tell us that
the bulk-to-boundary map at late times must be non-isometric. This implie
s that a large set of states in the effective field theory Hilbert space o
f the black hole interior do not exist in the fundamental description of t
he system. Despite this\, I will show using a simple model that several fe
atures of the effective field theory can be approximately preserved in the
fundamental theory\, as long as we restrict to states and operators whose
complexity is sub-exponential in the black hole entropy.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/74/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Venkatesa Chandrasekaran
DTSTART:20220927T120000Z
DTEND:20220927T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/75
DESCRIPTION:Title: Large N algebras and generalized entropy\nby Venkatesa C
handrasekaran as part of CERN String Seminars\n\n\nAbstract\nI will discus
s recent work on studying operator algebras in semiclassical gravity. In A
dS/CFT\, for two-sided black holes\, the large N limit of single-trace ope
rators in the boundary CFT results in a type III von Neumann algebra. Quan
tizing the relative timeshift between the two boundaries and including thi
s mode in the algebra promotes it to type II\, which allows the von Neuman
n entropy to be defined and calculated. I will first describe how this wor
ks for semiclassical perturbations around the microcanonical TFD state\, a
nd show that the von Neumann entropy agrees with the generalized entropy o
f the black hole. I will then apply the formalism to deSitter spacetime\,
and discuss implications for the entropy of the static patch.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/75/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tom Rudelius
DTSTART:20221004T120000Z
DTEND:20221004T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/76
DESCRIPTION:Title: Sharpening the Distance Conjecture in Diverse Dimensions
\nby Tom Rudelius as part of CERN String Seminars\n\n\nAbstract\nThe Dista
nce Conjecture holds that any infinite-distance limit in the scalar field
moduli space of a consistent theory of quantum gravity must be accompanied
by a tower of light particles whose masses scale exponentially with prope
r field distance ||𝜙|| as 𝑚∼exp(−𝜆||𝜙||)\, where 𝜆 is o
rder-one in Planck units. While the evidence for this conjecture is formid
able\, there is at present no consensus on which values of 𝜆 are allowe
d. In this talk\, I will propose a sharp lower bound on 𝜆 in 𝑑 space
time dimensions: 𝜆≥1/𝑑−2‾‾‾‾‾√. I will provide sever
al lines of evidence for this bound and discuss its implications for scala
r field potentials and cosmology.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/76/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Henry Lin
DTSTART:20221011T143000Z
DTEND:20221011T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/77
DESCRIPTION:Title: The bulk Hilbert space of double scaled SYK\nby Henry Li
n as part 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 qu
estion in the context of the SYK model in the double scaling limit. Berkoo
z et. al computed correlation functions in this model by summing chord dia
grams. By slicing open these chord diagrams\, I will explicitly construct
the bulk Hilbert space\; it resembles that of a lattice field theory where
the length of the lattice is dynamical and determined by the chord number
. Under a calculable bulk-to-boundary map\, states of fixed chord number m
ap to particular entangled 2-sided states with a corresponding size. This
bulk reconstruction is well-defined even when quantum gravity effects are
important. Acting on the double scaled Hilbert space is a Type II_1 algebr
a of observables\, which includes the Hamiltonian and matter operators. In
the appropriate quantum Schwarzian limit\, we also identify the JT gravit
ational algebra including the physical SL(2\,R) symmetry generators\, and
obtain explicit representations of the algebra using chord diagram techniq
ues.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/77/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zahra Zahraee
DTSTART:20221018T120000Z
DTEND:20221018T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/78
DESCRIPTION:Title: Non-relativistic physics in AdS and its CFT dual\nby Zah
ra Zahraee as part of CERN String Seminars\n\n\nAbstract\nIn this talk we
will discuss aspects of the non-relativistic two-body problems in AdS spac
etime and their CFT duals. Specifically\, we will define CFT correlation f
unctions that describe the NR dynamics in the bulk. We will then use them
to understand the spectrum of double-twist operators as well as flat spac
e scattering.\n \nIn more detail\, we will see how the S-channel OPE expan
sion of this correlator becomes the sum over states of the non-relativisti
c Hamiltonian. We will then use this to understand the spectrum from quant
um perturbation theory in the bulk. We will conclude this analysis by comp
aring our result with the output from Lorentzian inversion formula. Lastl
y\, we show how inserting an additional real time evolution in our correla
tor in the flat space limit yields the usual scattering amplitude.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/78/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mr Ohad Mamroud
DTSTART:20221025T130000Z
DTEND:20221025T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/79
DESCRIPTION:Title: The Supersymmetric Index and its Holographic Interpretation<
/a>\nby Mr Ohad Mamroud as part of CERN String Seminars\n\n\nAbstract\nThe
supersymmetric index of N=4 SU(N) Super Yang-Mills is a well studied quan
tity. In 2104.13932\, we analyzed it using the Bethe Ansatz approach\, exp
ressed 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 contribu
tion of a different euclidean black hole to the partition function of the
dual gravitational theory. By taking into account non-perturbative contrib
utions (wrapped D3-branes)\, we further showed a one to one match between
the contributions of the gravitational saddles and this family of contribu
tions to the index\, both at the perturbative and non-perturbative levels.
I'll end with some newer results\, concerning the form of these terms at
finite N\, and new solutions to the Bethe Ansatz equations (i.e. additiona
l contributions to the index beyond the ones described in that paper).\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/79/
END:VEVENT
BEGIN:VEVENT
SUMMARY:José Calderón-Infante
DTSTART:20221101T130000Z
DTEND:20221101T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/80
DESCRIPTION:Title: Pushing the Limits of the Swampland Distance Conjecture\
nby José Calderón-Infante as part of CERN String Seminars\n\n\nAbstract\
nThe goal of this talk is to push the limits of the Swampland Distance Con
jecture (SDC). This is one of the most relevant conjectures in the Swampla
nd program\, whose aim is to identify the criteria that an effective field
theory must satisfy in order to be consistently coupled to quantum gravit
y. For this purpose\, we study the SDC in two different contexts: Running
solutions and AdS/CFT.\n\nWe start by presenting a first example of runnin
g solution and its interplay with the SDC. Inspired by this\, we propose t
hat consistency of the SDC along the RG flow of the theory imposes constra
ints on the potentials that are attainable in quantum gravity. By studying
this constraints\, a new formulation of this conjecture is elucidated: th
e Convex Hull SDC. We then move to another type of running solutions\, the
so-called dynamical cobordisms. They receive this name for being the spac
etime realization of cobordisms between different theories. We uncover som
e universal behavior for dynamical cobordisms to nothing\, and relate them
to the Distance\, Cobordism and asymptotic dS conjectures. Finally\, we t
urn our attention to the SDC in the context of AdS/CFT. From the CFT persp
ective\, this conjecture is naturally realized at weak coupling points in
which some sector decouples. We then perform some purely CFT analysis in t
he context of 4d \\mathcal{N}=2 theories. This provides the first piece of
evidence for the SDC beyond String Theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/80/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Florian Loebbert
DTSTART:20221122T130000Z
DTEND:20221122T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/81
DESCRIPTION:Title: Fishnet Integrals from Integrability and Geometry\nby Fl
orian Loebbert as part of CERN String Seminars\n\n\nAbstract\nThe computat
ion of Feynman integrals still represents a bottle neck for precision calc
ulations in quantum field theory. Recent progress goes hand in hand with t
he understanding of new function classes and their mathematical structure.
In this talk we discuss the so-called fishnet integrals that represent an
infinite family of scalar Feynman integrals featuring integrable structur
es. In particular we review the Yangian quantum group symmetry of these in
tegrals which extends the conformal spacetime symmetry of the associated f
ishnet quantum field theories. We then focus on the specific case of fishn
ets in two spacetime dimensions and argue that these integrals compute the
quantum volumes of Calabi-Yau varieties. Here the Yangian provides a conv
enient tool that yields the Picard-Fuchs differential equations for the Ca
labi-Yau periods\, while the geometry dictates the particular linear combi
nation of periods\, which furnishes the Feynman integrals.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/81/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefano Negro
DTSTART:20221129T103000Z
DTEND:20221129T113000Z
DTSTAMP:20260404T093135Z
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\
nAbstract\nn the last few years\, much attention has been devoted to the s
tudy of a peculiar class of irrelevant deformations of 2-dimensional Quant
um Field Theories\, known as “Solvable Irrelevant Deformations”. The p
oster child of these is the celebrated “TTbar deformation”. They displ
ay unusual properties in the UV\, which can be described exactly\, their i
rrelevant nature notwithstanding. For this reason they represent a sensibl
e extension of Quantum Field Theory beyond the Wilsonian paradigm and have
attracted a considerable attention from the high energy theory community.
The property of being solvable is shared with a wider class of deformatio
ns\, constructed out of pairs of conserved currents. In general these are
marginal deformations\, thus presenting very different UV properties. None
theless their structures are similar to the TTbar ones\, hinting at the ex
istence of a universal description.\n \nIn this talk I will present a very
general framework that accommodates both solvable irrelevant and solvable
marginal deformations\, which amounts to a “topological gauging” of t
he symmetries of the system. Through simple path integral computations\, I
will recover the main features of these theories and show their equivalen
ce to TST and Yang-Baxter deformations. For the case of TTbar\, the topolo
gical gauging perspective explains the previously not understood relation
to field theory in non-commutative Minkowski space-time and to the central
ly extended Poincaré algebra.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/82/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alvaro Herraez
DTSTART:20221201T130000Z
DTEND:20221201T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/83
DESCRIPTION:Title: The Emergence Proposal in Quantum Gravity and the Species Sc
ale\nby Alvaro Herraez as part of CERN String Seminars\n\n\nAbstract\n
The Emergence Proposal claims that in Quantum Gravity the kinetic terms of
the fields in the IR can be understood as emergent from integrating out (
infinite) towers of particles up to the QG cutoff. After introducing this
proposal in the context of the Swampland Program and its relation to the D
istance and Weak Gravity Conjectures\, I will explain why it is natural to
identify this QG cutoff with the Species Scale\, motivating it by direct
computation in the presence of the relevant towers. Then\, I will present
evidence for this proposal by directly studying how it is realized in diff
erent string theory setups\, where the kinetic terms of scalars\, p-forms
and even scalar potentials can be shown to be consistent with emergence af
ter integrating out such towers.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/83/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter
DTSTART:20221206T130000Z
DTEND:20221206T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/84
DESCRIPTION:Title: Large p from SL(2\,Z)\nby Eric Perlmutter as part of CER
N String Seminars\n\n\nAbstract\nWe present formulas for a family of integ
rated correlators in 4d maximally supersymmetric SU(N) super Yang-Mills th
eory\, labeled by arbitrary rank N and arbitrary SU(4) charge p. This give
s rise to exact results at large charge\, for any rank N and complexified
gauge coupling \\tau (including various double-scaling limits). We discuss
features of this expansion\, and contrast with known results for extremal
two-point functions in superconformal QCD. Our computations are greatly f
acilitated by the use of SL(2\,Z) spectral theory.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/84/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Erik Tonni
DTSTART:20221213T130000Z
DTEND:20221213T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/85
DESCRIPTION:Title: Entanglement entropies for Lifshitz fermionic fields at fini
te density\nby Erik Tonni as part of CERN String Seminars\n\n\nAbstrac
t\nThe entanglement entropies of an interval for the free fermionic spinle
ss Schroedinger field theory at finite density and zero temperature are in
vestigated. The interval is either on the line or at the beginning of the
half line\, when either Neumann or Dirichlet boundary conditions are impos
ed at the origin. We show that the entanglement entropies are finite funct
ions of a dimensionless parameter proportional to the area of the rectangu
lar region in the phase space identified by the Fermi momentum and the len
gth of the interval. \nFor the interval on the line\, the entanglement en
tropy is a monotonically increasing function. Instead\, for the interval o
n the half line\, it displays an oscillatory behaviour related to the Frie
del oscillations of the mean particle density at the entangling point. \n
By employing the properties of the prolate spheroidal wave functions or th
e expansions of the tau functions of the kernels occurring in the spectral
problems\, determined by the two point function\, we find analytic expres
sions for the expansions of the entanglement entropies in the asymptotic r
egimes of small and large area of the rectangular phase space region. Exte
nding our analysis to a class of free fermionic Lifshitz models\, we find
that the parity of the Lifshitz exponent determines the properties of the
bipartite entanglement.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/85/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ji Hoon Lee
DTSTART:20230117T153000Z
DTEND:20230117T173000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/86
DESCRIPTION:Title: Computing bulk microstates\nby Ji Hoon Lee as part of CE
RN String 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 t
alk\, I present an exact formula that relates the BPS sectors of U(N) gaug
e theories and their string duals. The formula expresses the finite N supe
rconformal index of a U(N) gauge theory as a sum over stacks of bulk giant
graviton branes. I explain how to holographically construct the indices o
f bulk string/brane configurations by analyzing the modifications of deter
minant operators in gauge theory. Finally\, I discuss implications for bla
ck holes and the bulk BPS Hilbert space. Based on 2109.02545 and 2204.0928
6.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/86/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arjun Kar
DTSTART:20230124T153000Z
DTEND:20230124T173000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/87
DESCRIPTION:Title: A Celestial Matrix Model\nby Arjun Kar as part of CERN S
tring Seminars\n\n\nAbstract\nUnderstanding the proper formulation of AdS
holography in two spacetime dimensions has led to fascinating progress in
several directions. The main novel ingredient compared to higher dimensio
ns is that the asymptotic behavior of the metric is only "nearly'' AdS in
a certain precise sense. This difference allows for a very simple theory\
, Jackiw-Teitelboim gravity\, to have a non-perturbative completion as a H
ermitian 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-Ja
ckiw gravity\, to have a non-perturbative completion as a random matrix mo
del. We will discuss the Lorentzian and Euclidean formulations of this mo
del\, challenges in computing its non-perturbative scattering matrix\, and
which of its lessons are potentially applicable to four-dimensional celes
tial holography.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/87/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Murat Kologlu
DTSTART:20230131T153000Z
DTEND:20230131T173000Z
DTSTAMP:20260404T093135Z
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 asym
ptotic detector operators in weakly-coupled field theories. Detector opera
tors describe measurements that can be performed at future null infinity i
n a collider experiment. The set of detectors depends on the dynamics of t
he theory. In a conformal field theory\, detectors are identified with lig
ht-ray operators\, thus bearing a direct relation to the spectrum of the t
heory. I will discuss how to renormalize the infrared divergences of gener
al detector operators in perturbation theory\, leading to detector anomalo
us dimensions. Our formalism allows for the resolution of intersections of
Regge trajectories where nontrivial mixing occurs. Working with the Wilso
n-Fisher theory as an example\, I will present an explicit expression for
the Pomeron light-ray operator\, as well as an improved prediction for the
Regge intercept. Finally\, I will discuss novel “Reggeized scalar” tr
ajectories.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/88/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kristan Jensen
DTSTART:20230207T153000Z
DTEND:20230207T173000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/89
DESCRIPTION:Title: A precision test of averaging in AdS/CFT\nby Kristan Jen
sen as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/89/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiara Paletta
DTSTART:20230214T130000Z
DTEND:20230214T150000Z
DTSTAMP:20260404T093135Z
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://stable.researchseminars.org/talk/CERNStringSem/90/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Iliesiu
DTSTART:20230221T130000Z
DTEND:20230221T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/91
DESCRIPTION:Title: Black hole microstate counting from the gravitational path i
ntegral\nby Luca Iliesiu as part of CERN String Seminars\n\n\nAbstract
\nReproducing the integer count of black hole micro-states from the gravit
ational path integral is an important problem in quantum gravity. In this
paper\, we show that\, by using supersymmetric localization\, the gravitat
ional path integral for 1/16-BPS black holes in supergravity reproduces th
e index obtained in the string theory construction of such black holes\, i
ncluding all non-perturbatively suppressed geometries. A more refined argu
ment then shows that not only the black hole index but also the total numb
er of black hole microstates within an energy window above extremality tha
t is polynomially suppressed in the charges also matches this string theor
y index. To achieve such a match\, we compute the one-loop determinant ari
sing in the localization calculation for all N=2 supergravity supermultipl
ets in the N=8 gravity supermultiplet. Furthermore\, we carefully account
for the contribution of boundary zero-modes\, which can be seen as arising
from the zero-temperature limit of the N=4 super-Schwarzian\, and show th
at performing the exact path integral over such modes provides a critical
contribution needed for the match to be achieved.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/91/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luca Delacretaz
DTSTART:20230228T130000Z
DTEND:20230228T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/92
DESCRIPTION:Title: Nonlinear Effective Field Theory of Fermi Liquids\nby Lu
ca Delacretaz as part of CERN String Seminars\n\n\nAbstract\nLandau's theo
ry of Fermi liquids is a cornerstone of theoretical physics. I will show h
ow to formulate Fermi liquid theory as an effective field theory of bosoni
c degrees of freedom\, using the mathematical formalism of coadjoint orbit
s. While at the linear level\, this theory reduces to existing multidimens
ional bosonization approaches\, it necessarily features nonlinear correcti
ons that are fixed by the geometry of the Fermi surface. These are crucial
to reproduce nonlinear response\, such as higher-point functions of curre
nts. The effective field theory framework furthermore systematically param
etrizes corrections to Fermi liquid behavior\, and provides a computationa
lly advantageous approach for non-Fermi liquids -- strongly interacting fi
xed points obtained by deforming Fermi liquids with relevant interactions.
\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/92/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marija Tomašević
DTSTART:20230307T130000Z
DTEND:20230307T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/93
DESCRIPTION:Title: Holographic duals of evaporating black holes\nby Marija
Tomašević as part of CERN String Seminars\n\n\nAbstract\nWe describe the
dynamical evaporation of a black hole as the classical evolution in time
of a black hole in an Anti-de Sitter braneworld. A bulk black hole whose h
orizon intersects the brane yields the classical bulk dual of a black hole
coupled to quantum conformal fields. The evaporation of this black hole h
appens when the bulk horizon slides off the brane\, making the horizon on
the brane shrink. We use a large-D effective theory of the bulk Einstein e
quations to solve the time evolution of these systems. With this method\,
we study the dual evaporation of a variety of black holes interacting with
colder radiation baths. We also obtain the dual of the collapse of hologr
aphic radiation to form a black hole on the brane.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/93/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Lupsasca
DTSTART:20230314T130000Z
DTEND:20230314T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/94
DESCRIPTION:Title: The Black Hole Photon Ring\nby Alex Lupsasca as part of
CERN String Seminars\n\n\nAbstract\nWhat does a black hole look like? The
first images of the supermassive black hole M87* display a bright ring enc
ircling the event horizon\, which appears as a dark patch in its surroundi
ng emission. But Einstein's theory of general relativity predicts that wit
hin this 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-ti
me geometry just outside its horizon. The photon ring carries an imprint o
f the strong gravity in this region and encodes fundamental properties of
the black hole (including\, for instance\, its quasinormal mode spectrum).
A measurement of this predicted (but not yet observed) ring could provide
a precise test of general relativity and will be the target of a NASA mis
sion proposed to fly within the next decade.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/94/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Stout
DTSTART:20230321T130000Z
DTEND:20230321T150000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/95
DESCRIPTION:Title: Infinite Distance Limits and Factorization\nby John Stou
t as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/95/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Timo Weigand
DTSTART:20230328T120000Z
DTEND:20230328T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/96
DESCRIPTION:Title: Quantum Gravity Bounds on 4D EFTs with Minimal Supersymmetry
\nby Timo Weigand as part of CERN String Seminars\n\n\nAbstract\nAccor
ding to the Swampland idea\, quantum gravity effects put severe constraint
s on effective field theories beyond the usual consistency conditions from
quantum field theory such as absence of gauge or gravitational anomalies.
In this talk\, we propose such constraints for four-dimensional N=1 super
gravities based on consistency of certain axionic\, or EFT\, strings. Thes
e are certain strings which are magnetically charged under the axionic com
ponents of the chiral N=1 superfields\; their existence follows from the
Completeness Conjecture in quantum gravity. The key observation is that an
omaly inflow from the four-dimensional theory to the string worldsheet ind
uces anomalies on the string which must be cancelled by local anomalies on
the string. This results in various quantisation conditions as well as bo
unds on the signs of axionic couplings in the supergravity\, including the
sign of the Gauss-Bonnet term\, and also bounds on the rank of the gauge
group in terms of these Gauss-Bonnet couplings. These constraints can rule
out supergravity theories which otherwise look perfectly healthy as effe
ctive field theories of quantum gravity. We also test the proposed constra
ints by comparing them with explicit string models\, in particular with F-
theory compactifications to four dimensions.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/96/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Beatrix Mühlmann
DTSTART:20230404T120000Z
DTEND:20230404T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/97
DESCRIPTION:Title: Matrix duality in twistor space\nby Beatrix Mühlmann as
part of CERN String Seminars\n\n\nAbstract\nIn this talk I consider loop
integrands for correlators of “master” operators in N=4 SYM. Loop int
egrands are Born-level correlators in the self-dual sector\nof N = 4 SYM\,
while master operators are determinant operators which serve as generatin
g functions of all single-trace half-BPS operators. \nWorking in twistor s
pace and using matrix duality I will reformulate these integrands in terms
of a matrix integral which also manifests a\n10 dimensional structure tha
t combines spacetime and R-charge symmetries.\n\nThis talk is based on wor
k in progress with S. Caron-Huot and F. Coronado.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/97/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jie Gu
DTSTART:20230411T090000Z
DTEND:20230411T110000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/98
DESCRIPTION:Title: TH String Theory Seminar\nby Jie Gu as part of CERN Stri
ng Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/98/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sunil Mukhi
DTSTART:20230425T120000Z
DTEND:20230425T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/99
DESCRIPTION:Title: Classification of Rational Conformal Field Theories With A S
ingle Critical Exponent\nby Sunil Mukhi as part of CERN String Seminar
s\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/99/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jacob McNamara
DTSTART:20230502T143000Z
DTEND:20230502T163000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/100
DESCRIPTION:Title: Reflections on Parity Breaking\nby Jacob McNamara as pa
rt of CERN String Seminars\n\n\nAbstract\nOne approach to the Strong CP Pr
oblem (known as Nelson-Barr models) is to assume that parity is a gauge sy
mmetry\, which is spontaneously broken in the world around us. In this tal
k\, I will argue that the domain walls formed from spontaneous parity brea
king are exactly stable. This stability can be understood as the result of
an unusual sort of conserved charge\, which has features in common with b
oth gauge charges and global charges. We will explain how these charges ar
e compatible with the expected absence of global symmetries in quantum gra
vity\, as well as their relationship with the Swampland Cobordism Conjectu
re.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/100/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tomáš Procházka
DTSTART:20230509T120000Z
DTEND:20230509T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/101
DESCRIPTION:Title: Bethe ansatz in 2d conformal field theory\nby Tomáš P
rocházka as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/101/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nathan Benjamin
DTSTART:20230516T143000Z
DTEND:20230516T163000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/102
DESCRIPTION:Title: The statistics of spins for CFTs\nby Nathan Benjamin as
part of CERN String Seminars\n\n\nAbstract\nI will discuss universal beha
vior of CFT data at high energies. In particular I will discuss universal
formulas for both the entropy and the three-point-functions of local opera
tors for d-dimensional CFT (d>2) as a function of energy and spin\, using
a technique called thermal effective field theory. This result can be thou
ght of as a higher-dimensional version of Cardy's formula for 2d CFTs. I w
ill also discuss holographic interpretations of this result. Based on work
to appear with J. Lee\, H. Ooguri\, and D. Simmons-Duffin.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/102/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sašo Grozdanov
DTSTART:20230523T120000Z
DTEND:20230523T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/103
DESCRIPTION:Title: Spectra\, reconstructions and pole-skipping\nby Sašo G
rozdanov as part of CERN String Seminars\n\n\nAbstract\nThe poles of two-p
oint functions in momentum space\, which can be computed and analysed usin
g holographic methods\, reveal various details of the physical properties
of spectra in QFTs. In thermal QFTs\, the lowest-energy (IR) gapless mode
is usually described by the theory of hydrodynamics. Assuming a known disp
ersion relation of only a single hydrodynamic mode\, I will discuss when a
nd how the reconstruction of the complete spectrum of physical excitations
is possible in the corresponding correlator. In particular\, I will demon
strate our recently developed constructive algorithm based on the theorems
of Darboux and Puiseux that allows for a reconstruction of all modes conn
ected by `level-crossings’ in the associated spectral curve\, from IR to
UV. In the second part of my talk\, I will introduce the phenomenon of po
le-skipping (formally\, a “0/0”) in such correlators and discuss how i
ts knowledge can itself be sufficient to reconstruct the entire spectrum.\
n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/103/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nima Lashkari
DTSTART:20230620T120000Z
DTEND:20230620T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/104
DESCRIPTION:Title: Information loss\, and emergent type III1 algebras in time<
/a>\nby Nima Lashkari as part of CERN String Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/104/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sumit Das
DTSTART:20230718T120000Z
DTEND:20230718T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/105
DESCRIPTION:Title: Entanglement of Internal Degrees of Freedom\, Finiteness an
d Holography\nby Sumit Das as part of CERN String Seminars\n\n\nAbstra
ct\nI will discuss notions of entanglement of internal degrees of freedom
in theories of large N matrices. Along with usual base space entanglement\
, this kind of entanglement (which do not pertain to a subregion of base s
pace) should play a key role in holography\, particularly in the emergence
of a smooth internal space in the bulk. One such notion is target space e
ntanglement\, which appears as entanglement of D branes in the bulk. For t
he c=1 Matrix Model we will show how the target space entanglement entropy
is perturbatively divergent\, but non-perturbatively finite. Yet another
notion relates to geometriztion of internal symmetries\, as in familiar ex
amples of holography n AdS X Y. We provide evidence that the entropy of t
his kind of entanglement is measured by Ryu-Takayanagi surfaces which are
smeared along the AdS directions\, and anchored on a subregion of the inte
rnal space Y.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/105/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony
DTSTART:20231009T140000Z
DTEND:20231009T160000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/106
DESCRIPTION:Title: Correlation functions in TT*-deformed conformal field theor
ies\nby Ofer Aharony as part of CERN String Seminars\n\nAbstract: TBA\
n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/106/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vasilis Niarchos
DTSTART:20231010T120000Z
DTEND:20231010T140000Z
DTSTAMP:20260404T093135Z
UID:CERNStringSem/107
DESCRIPTION:Title: Bootstrability with Improved Truncation Methods\nby Vas
ilis Niarchos as part of CERN String Seminars\n\n\nAbstract\nI will discus
s recent work on the numerical conformal bootstrap that modifies the scope
of the so-called truncation methods and improves their efficiency. I will
show how the proposed approach performs in the recently discussed context
of bootstrability for 1d defect CFTs on 1/2 BPS Wilson lines in 4d N=4 SY
M theory\, how it compares with the more standard linear functional method
and how different algorithms allow us to tackle the large-scale non-conve
x optimization problems that are involved in this method. Along the way\,
I will address the prospects of AI and Machine Learning in this particular
direction.\n
LOCATION:https://stable.researchseminars.org/talk/CERNStringSem/107/
END:VEVENT
END:VCALENDAR