BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Aristomenis Donos (Durham University)
DTSTART:20200512T111500Z
DTEND:20200512T121500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/1
DESCRIPTION:Title: Vortex Lattices From Holography\nby Aristomenis Donos (Durham Univers
ity) as part of CCTP HEP Seminars\n\n\nAbstract\nVortices are fascinating
stable configurations of electric currents that occur in the broken phase
of superconductors. Based on an effective field theory approach\, Abrikoso
v argued that when the force between them is repulsive\, stable periodic c
onfigurations can form. In my talk I will consider similar constructions f
or superfluids away from the critical temperature. Moreover\, I will discu
ss how known field theories can exhibit phases which are not captured by A
brikosov's considerations.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dimitrios Giataganas (NKUA)
DTSTART:20200519T111500Z
DTEND:20200519T121500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/2
DESCRIPTION:Title: Anisotropic holography\nby Dimitrios Giataganas (NKUA) as part of CCT
P HEP Seminars\n\n\nAbstract\nStrongly coupled anisotropic systems have si
gnificantly richer structure than the isotropic ones. This is especially e
vident in the transport coefficients and in the phase diagram of anisotrop
ic theories. We discuss such holographic theories\, we comment on their ob
servables and demonstrate how the isotropic universal relations are violat
ed in presence of anisotropies. We also propose c-function candidates for
the anisotropic RG flows and show that their monotonicity is not any more
guaranteed by the energy conditions but depends on the theory characterist
ics.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Achilleas Porfyriadis (Harvard University)
DTSTART:20200526T131500Z
DTEND:20200526T141500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/3
DESCRIPTION:Title: The connection problem for AdS2\nby Achilleas Porfyriadis (Harvard Un
iversity) as part of CCTP HEP Seminars\n\n\nAbstract\nI will talk about th
e problem of extending anti-de Sitter solutions away from the near-horizon
region of (near-)extreme black holes and connecting them with solutions i
n the black holes far asymptotically flat region. In Part I of the talk I
will present analytic solutions to the connection problem for coupled grav
itational and electromagnetic perturbations of AdS2xS2 and near-AdS2xS2 in
the extreme and near-extreme Reissner-Nordstrom black holes\, respectivel
y. In Part II of the talk I will discuss a calculation of backreaction in
AdS2. In this calculation\, an AdS2xS2 throat geometry reacts to a perturb
ation by a scalar field in such a way that\, with leaky boundary condition
s\, it maintains its connection to the far asymptotically flat region of t
he black hole.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefanos Kousvos (UOC)
DTSTART:20200528T111500Z
DTEND:20200528T121500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/4
DESCRIPTION:Title: Bootstrapping theories with $O(m)\\times O(n)$ global symmetry in three d
imensions\nby Stefanos Kousvos (UOC) as part of CCTP HEP Seminars\n\n\
nAbstract\nI will discuss recent work performed with Johan Henriksson and
Andreas Stergiou studying O(m)xO(n) conformal field theories in three dime
nsions. Motivated by phase transitions in three-dimensional systems\, as w
ell as open theoretical questions\, we will focus on the $O(2)\\times O(n)
$ case. We study different values of $n$\, for $n$ sufficiently large we f
ind excellent agreement with large $n$ predictions for scaling dimensions
of operators. For $n=3$ we find closed isolated regions (islands) in param
eter space that do not correspond to the ordinary fixed points of the $d=4
-e$ expansion\, we attribute these regions of parameter space to fixed poi
nts conjectured to arise due to resummations of perturbative beta function
s.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jelle Hartong (University of Edinburg)
DTSTART:20200602T101500Z
DTEND:20200602T111500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/5
DESCRIPTION:Title: Dynamics of Fluids without Boost Symmetries\nby Jelle Hartong (Univer
sity of Edinburg) as part of CCTP HEP Seminars\n\n\nAbstract\nStandard tex
tbook treatments of fluid dynamics assume the presence of a boost symmetry
. This is either a Galilean boost symmetry or a Lorentzian one and leads t
o the Navier-Stokes equations or their relativistic counterpart. It is how
ever not necessary to rely on a boost symmetry as one can treat velocity a
s the chemical potential associated with momentum conservation. In fact fo
r fluids moving through a medium one expects boost symmetries to be generi
cally broken. This includes the case of scale invariant Lifshitz fluids. I
n this talk I will present the general treatment of fluid dynamics without
boost symmetries and I will show that there can be 10 dissipative and 6 n
on-dissipative transport coefficients (of which 2 are hydrostatic and 4 ar
e not) for uncharged non-boost invariant fluid dynamics. Time permitting\,
I will discuss some general ideas regarding holographic realisations of n
on-boost invariant Lifshitz fluids.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihalis Dafermos (Cambridge and Princeton University)
DTSTART:20200609T101500Z
DTEND:20200609T111500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/6
DESCRIPTION:Title: Strong Cosmic Censorship versus Λ\nby Mihalis Dafermos (Cambridge an
d Princeton University) as part of CCTP HEP Seminars\n\n\nAbstract\nThe st
rong cosmic censorship conjecture is a fundamental open problem in classic
al general relativity\, first put forth by Roger Penrose in the early 70s.
This is essentially the question of whether general relativity is a deter
ministic theory. Perhaps the most exciting arena where the validity of the
conjecture is challenged is the interior of rotating black holes\, and th
ere has been a lot of work in the past 50 years in identifying mechanisms
ensuring that at least some formulation of the conjecture be true. It turn
s out that when a nonzero cosmological constant Λ is added to the Einstei
n equations\, these underlying mechanisms change in an unexpected way\, an
d the validity of the conjecture depends on a detailed understanding of su
btle aspects of black hole scattering theory\, surprisingly involving\, in
the case of negative Λ\, some number theory. Does strong cosmic censorsh
ip survive the challenge of non-zero Λ? This talk will try to address thi
s Question!\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Van Raamsdonk (University of British Columbia)
DTSTART:20200623T160000Z
DTEND:20200623T170000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/7
DESCRIPTION:Title: The holographic CFT masquerade\nby Mark Van Raamsdonk (University of
British Columbia) as part of CCTP HEP Seminars\n\n\nAbstract\nWe argue tha
t given holographic CFT1 in some state with a dual spacetime geometry M\,
and given some other holographic CFT2\, we can find states of CFT2 whose d
ual geometries closely approximate arbitrarily large causal patches of M\,
provided that CFT1 and CFT2 can be non-trivially coupled at an interface.
Our CFT2 states are ``dressed up as'' states of CFT1: they are obtained f
rom the original CFT1 state by a regularized quench operator defined using
a Euclidean path-integral with an interface between CFT2 and CFT1. Our re
sults are consistent with the idea that the precise microscopic degrees of
freedom and Hamiltonian of a holographic CFT are only important in fixing
the asymptotic behavior of a dual spacetime\, while the interior spacetim
e of a region spacelike separated from a boundary time slice is determined
by more universal properties (such as entanglement structure) of the quan
tum state at this time slice. Our picture requires that low-energy gravita
tional theories related to CFTs that can be non-trivially coupled at an in
terface are part of the same non-perturbative theory of quantum gravity.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Moschidis (University of California Berkeley)
DTSTART:20200630T101500Z
DTEND:20200630T111500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/8
DESCRIPTION:Title: The instability of Anti-de Sitter spacetime\nby Georgios Moschidis (U
niversity of California Berkeley) as part of CCTP HEP Seminars\n\n\nAbstra
ct\nAccording to the AdS instability conjecture\, there exist arbitrarily
small perturbations to the initial data of AdS spacetime which\, under evo
lution by the vacuum Einstein equations with reflecting boundary condition
s on conformal infinity\, lead to the formation of black holes after suffi
ciently long time. To this day\, the question about the vacuum equations r
emains open (and poorly understood). However\, during the last decade\, a
large number of numerical and heuristic works have been dedicated to addre
ssing the conjecture in the presence of matter fields allowing spherically
symmetric dynamics. In this talk\, I will review the progress achieved so
far in addressing the AdS instability conjecture and I will present a rig
orous proof of the instability in the setting of the spherically symmetric
Einstein--scalar field system. The proof will be based on the non-linear
interactions of special configurations of matter beams. The possible exten
sion of the main ideas to the vacuum case will also be discussed.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Panagiotis Betzios (University of Crete)
DTSTART:20200702T101500Z
DTEND:20200702T111500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/9
DESCRIPTION:Title: Liouville theory and Matrix models - A Wheeler DeWitt perspective\nby
Panagiotis Betzios (University of Crete) as part of CCTP HEP Seminars\n\n
\nAbstract\nWe analyse the connections between the Wheeler DeWitt approach
for two dimensional quantum gravity and holography\, focusing mainly in t
he case of Liouville theory coupled to c = 1 matter. Our motivation is to
understand whether some form of averaging is essential for the boundary th
eory\, if we wish to describe the bulk quantum gravity path integral of th
is two dimensional example. The analysis hence\, is in a spirit similar to
the recent studies of Jackiw-Teitelboim (JT)-gravity. Macroscopic loop op
erators define the asymptotic region on which the holographic boundary dua
l is expected to reside. Matrix quantum mechanics (MQM) and the associated
double scaled fermionic field theory on the contrary\, is providing an ex
plicit "unitary in superspace" description of the complete dynamics of suc
h two dimensional universes with matter\, including the effects of topolog
y change. If we try to associate a Hilbert space to a single boundary dual
\, it seems that it cannot contain all the information present in the non-
perturbative bulk quantum gravity path integral and MQM.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constantin Bachas (ENS Paris)
DTSTART:20200714T100000Z
DTEND:20200714T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/10
DESCRIPTION:Title: Energy transmission at holographic interfaces\nby Constantin Bachas
(ENS Paris) as part of CCTP HEP Seminars\n\n\nAbstract\nI will describe th
e first gravitational calculation of the universal energy transmission and
reflection coefficients of 2D conformal interfaces with holographic duals
. The result is a monotonic function of the dual brane tension. It is cons
istent with the ANEC bound (which is stricter than the positivity bound in
the Euclidean theory).\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bzowski (University of Crete)
DTSTART:20200908T100000Z
DTEND:20200908T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/11
DESCRIPTION:Title: Toy models for AdS black holes\nby Adam Bzowski (University of Crete
) as part of CCTP HEP Seminars\n\n\nAbstract\nI will present two simple to
y models exhibiting properties associated with quantum black holes. For th
e first model I will consider a quantum mechanical system of the double we
ll potential. The second model is obtained by coupling stress tensors of t
he two CFTs living on the boundaries of the BTZ black hole. The common the
me of both systems is that the Hilbert space of states does not admit the
usual factorization into a tensor product. Instead\, the semi-classical\,
low-energy physics is emergent and can be reinterpreted in terms of state-
dependence.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Domenico Orlando (University of Torino)
DTSTART:20200915T100000Z
DTEND:20200915T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/12
DESCRIPTION:Title: Introduction to the large charge expansion\nby Domenico Orlando (Uni
versity of Torino) as part of CCTP HEP Seminars\n\n\nAbstract\nWorking in
sectors of large global charge leads to important simplifications when stu
dying strongly coupled CFTs. In this talk I will introduce the large-charg
e expansion via the simple example of the O(2) model and apply it in a num
ber of other situations displaying a richer structure\, such as non-Abelia
n vector models\, supersymmetric N=2 systems and asymptotically safe theor
ies.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anatoly Dymarsky (University of Kentucky)
DTSTART:20200922T100000Z
DTEND:20200922T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/13
DESCRIPTION:Title: Quantum codes\, lattices\, and conformal field theories\nby Anatoly
Dymarsky (University of Kentucky) as part of CCTP HEP Seminars\n\n\nAbstra
ct\nThere is a deep relation between classical error-correcting\ncodes\, E
uclidean lattices\, and chiral 2d CFTs. We show this relation\nextends to
include quantum codes\, Lorentzian lattices\, and non-chiral\nCFTs. The re
lation to quantum codes provides a simple way to solve\nmodular bootstrap
constraints and identify interesting examples of\nconformal theories. In p
articular we construct many examples of\nphysically distinct isospectral t
heories\, examples of "would-be" CFT\npartition function -- non-holomorphi
c functions satisfying all\nconstraints of the modular bootstrap\, yet not
associated with any\nknown CFT\, and find theory with the maximal spectra
l gap among all\nNarain CFTs with the central charge c=4. We also discuss
averaging\nover the ensemble of all CFTs associated with quantum codes\, a
nd its\npossible holographic interpretation. The talk is based on\narXiv:2
009.01236 and arXiv:2009.01244.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioannis Matthaiakakis (Julius-Maximilians-Universitaet Wuerzburg)
DTSTART:20200924T100000Z
DTEND:20200924T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/14
DESCRIPTION:Title: Turbulent hydrodynamics in strongly correlated Kagome materials\nby
Ioannis Matthaiakakis (Julius-Maximilians-Universitaet Wuerzburg) as part
of CCTP HEP Seminars\n\n\nAbstract\nIn recent years a lot of interest has
been directed towards realizing strongly-coupled electronic fluids. This i
nterest is partly because a stronger coupling enables the transition to th
e hydrodynamic regime and partly because of the novel transport phenomena
such a fluid promises. Strongly-coupled fluids are also a natural and fert
ile ground for testing and refining our understanding of AdS/CFT and holog
raphy in general. In this talk\, I will first show that Kagome materials w
ith a relativistic spectrum are a compelling platform for realizing strong
ly-coupled fluids. Then\, I will employ holography to estimate their ratio
of shear viscosity to entropy density. With that estimate at hand\, I wil
l finally argue that strongly-coupled Kagome fluids put for the first time
non-linear hydrodynamic phenomena such as turbulence within experimental
reach.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Stergiou (Los Alamos National Laboratory)
DTSTART:20201006T140000Z
DTEND:20201006T150000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/15
DESCRIPTION:Title: Uncovering the Structure of the ε Expansion\nby Andreas Stergiou (L
os Alamos National Laboratory) as part of CCTP HEP Seminars\n\n\nAbstract\
nThe ε expansion was invented almost 50 years ago and has been used exten
sively ever since to quantitatively describe critical phenomena. Its most
famous applications are found in theories involving scalar fields in 4−
ε dimensions. In this talk\, we will be interested in the structure of th
e ε expansion of scalar field theories and the fixed points that can be o
btained within it. Our motivation is based on the goal of classifying conf
ormal field theories in d=3 dimensions. We will describe recently discover
ed universal constraints obtained within the framework of the ε expansion
\, focusing mostly on the 4−ε case although 3−ε will also be discuss
ed. It will be shown that a “heavy handed" way to search for fixed point
s yields a plethora of new fixed points that reveal aspects of the structu
re of the ε expansion and suggest that a classification of conformal fiel
d theories in d=3 is likely to be very non trivial. (Based on arXiv:1707.0
6165\, arXiv:1810.10541 and upcoming work with Hugh Osborn.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zohar Komargodski (Simons Center)
DTSTART:20201015T120000Z
DTEND:20201015T130000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/16
DESCRIPTION:Title: Symmetry\, Confinement and Naturalness\nby Zohar Komargodski (Simons
Center) as part of CCTP HEP Seminars\n\n\nAbstract\nWe will review the no
tion of extended symmetry and show how it can be applied for two dimension
al QCD. We will use extended symmetry to prove deconfinement and to comput
e the exact string tension when the quarks are light. Some interesting imp
lications for the naturalness of RG flows will be discussed as well.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Warner (Southern California University)
DTSTART:20200929T100000Z
DTEND:20200929T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/17
DESCRIPTION:Title: Tidal Trapping of Strings by Microstate Geometries\nby Nick Warner (
Southern California University) as part of CCTP HEP Seminars\n\n\nAbstract
\nI will describe the fate of a massless (or ultra-relativistic massive) s
tring probe propagating down the BTZ-like throat of a microstate geometry
in the D1-D5 system. Far down the throat\, the probe encounters large tida
l forces that stretch and excite the string. The excitations are limited b
y the very short transit time through the region of large tidal force\, le
ading to a controlled approximation to tidal stretching. The amount of str
etching is proportional to the incident energy\, and that it robs the prob
e of the kinetic energy it would need to travel back up the throat. As a c
onsequence\, the probe is effectively trapped far down the throat and\, th
rough repeated return passes\, scrambles into the ensemble of nearby micro
states. This tidal trapping can lead to weak gravitational echoes.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shai Chester (Weizmann Institute)
DTSTART:20201020T100000Z
DTEND:20201020T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/18
DESCRIPTION:Title: AdS/CFT at Finite String Coupling\nby Shai Chester (Weizmann Institu
te) as part of CCTP HEP Seminars\n\n\nAbstract\nWe study the N = 4 SU(N) s
uper-Yang-Mills stress tensor multiplet four-point function at large N and
finite complexified Yang-Mills coupling tau\, which is dual to the Type
IIB graviton correlator on AdS_5 × S^5 at large string length and finite
string coupling. The specific four-point functions we consider are integra
ted correlators obtained by taking various combinations of four derivative
s of m\, b\, and tau of the sphere free energy deformed by mass m and squa
shing parameter b\, which can be computed using supersymmetric localizatio
n. We show that at each order in 1/N\, these quantities can be written in
terms of modular invariants\, such as the well studied non-Holomorphic Eis
enstein series as well as some new generalizations thereof. These results
reproduce known features of the low-energy expansion of the four-graviton
amplitude in type IIB superstring theory in ten-dimensional flat space\, w
hich is the first check of AdS/CFT at finite string coupling\, and have in
teresting implications for the structure of the analogous expansion in AdS
_5 × S^5.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony (Weizmann Institute)
DTSTART:20201027T120000Z
DTEND:20201027T130000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/19
DESCRIPTION:Title: Little String Theory on Curved Manifolds\nby Ofer Aharony (Weizmann
Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nThis talk is based
on 1908.02642\, in collaboration with Evtikhiev and Feldman. After reviewi
ng Little String Theories (the decoupled theories on the worldvolume of N
NS5-branes) we will use their holographic duality to Type II string theory
in asymptotically linear dilaton backgrounds in order to study these theo
ries on curved space-times. We focus on backgrounds with a large number of
Killing vectors (namely\, products of maximally symmetric spaces)\, witho
ut requiring supersymmetry (we do not turn on any background fields except
the metric). Little String Theory is non-local so it is not obvious which
spaces it can be defined on\; we show that holography implies that the th
eory cannot be put on negatively curved spaces\, but only on spaces with z
ero or positive curvature. For example\, one cannot put Little String Theo
ry on a product of an anti-de Sitter space times another space\, without t
urning on extra background fields. On spaces with positive curvature\, suc
h as products of spheres\, we typically find (for large N) dual holographi
c backgrounds which are weakly coupled and weakly curved everywhere\, so t
hat they can be well-described by Type II supergravity. In some cases more
than one smooth solution exists for Little String Theory on the same spac
e\, and they all contribute to the partition function. We also study the t
hermodynamical properties of Little String Theory compactified on spheres\
, finding the leading correction to the Hagedorn behavior of the spectrum\
, which is different on curved space than on flat space.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou (University of British Columbia)
DTSTART:20201106T150000Z
DTEND:20201106T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/20
DESCRIPTION:Title: Inside the Hologram: The bulk observer's experience\nby Lampros Lamp
rou (University of British Columbia) as part of CCTP HEP Seminars\n\n\nAbs
tract\nI will present a holographic framework for reconstructing the exper
ience of bulk observers in AdS/CFT. In particular\, I will show how to rec
over the proper time and energy distribution measured along bulk worldline
s\, directly in the CFT via a universal\, background-independent prescript
ion. For an observer falling into an eternal AdS black hole\, the proposal
resolves a conceptual puzzle raised by Marolf and Wall. Notably\, the pre
scription does not rely on an external dynamical Hamiltonian or the AdS bo
undary conditions and is\, therefore\, outlining a general framework for t
he emergence of time\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Meltzer (Caltech)
DTSTART:20201013T140000Z
DTEND:20201013T150000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/23
DESCRIPTION:Title: The Inversion Formula and 3d CFTs\nby David Meltzer (Caltech) as par
t of CCTP HEP Seminars\n\n\nAbstract\nThe Lorentzian inversion formula pro
ves that CFT data is analytic in spin and that operators can be organized
on Regge trajectories. In this talk we investigate the leading Regge traje
ctories of the O(2) model using a combination of numerical and analytical
techniques. We find agreement between the two methods in various charge se
ctors of the O(2) CFT. Furthermore\, we find evidence that scalar operator
s lie on Regge trajectories and estimate the Regge intercept of the O(2) m
odel. Finally\, we use the analytic and numerical data to study non-Gaussi
anities in the charge-1 scalar four-point function.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexey Milekhin (Princeton University)
DTSTART:20201110T150000Z
DTEND:20201110T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/24
DESCRIPTION:Title: Humanly Traversable Wormholes\nby Alexey Milekhin (Princeton Univers
ity) as part of CCTP HEP Seminars\n\n\nAbstract\nIn my talk I will present
the construction of humanly traversable wormholes in four dimensions. The
construction is based on two magnetically charged black holes embedded in
to Randall-Sundrum model. In particular\, it does not need exotic matter o
r boundary conditions. It is a long wormhole that does not lead to causali
ty violations in the ambient space. I will explain why it is humanly trave
rsable and what could be the challenges for the travelling observer.\nThe
talk is based on arxiv.org/abs/2008.06618\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simon Caron Huot (McGill)
DTSTART:20201117T140000Z
DTEND:20201117T150000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/25
DESCRIPTION:Title: Gravity: the force from the UV\nby Simon Caron Huot (McGill) as part
of CCTP HEP Seminars\n\n\nAbstract\nDispersion relations are statements o
f causality. They give sum rules connecting infrared and ultraviolet physi
cs. While they originate in optics and quantum field theory\, I will argu
e that their 'true purpose' is gravity\, viewed as a low-energy effective
theory. This is due to the unique energy dependence of this force. I will
present ongoing work mapping out the space of consistent effective theori
es\, including recent results in scalar models (2011.02957)\, deriving a s
harp version of dimensional analysis scaling from causality.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefanos Aretakis (University of Toronto)
DTSTART:20201124T150000Z
DTEND:20201124T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/26
DESCRIPTION:Title: Asymptotics for the wave equation on black hole spacetimes\nby Stefa
nos Aretakis (University of Toronto) as part of CCTP HEP Seminars\n\n\nAbs
tract\nWe will present the precise late-time asymptotics for scalar fields
on both extremal and sub-extremal black holes including the full Reissner
-Nordstrom family and the subextremal Kerr family. Asymptotics for higher
angular modes will be presented for all cases. Applications in observation
al signatures will also be discussed. This work is joint with Y. Angelopou
los (Caltech) and D. Gajic (Cambridge)\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eliezer Rabinovici (Hebrew University of Jerusalem)
DTSTART:20201201T110000Z
DTEND:20201201T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/27
DESCRIPTION:Title: Quantum fluctuations and instantons\nby Eliezer Rabinovici (Hebrew U
niversity of Jerusalem) as part of CCTP HEP Seminars\n\n\nAbstract\nAfter
a review of Coleman's work on the fate of a false vacuum we turn to consid
er the decay involved in circumstances where the methods suggested by Cole
man run into difficulties. We find that in those cases quantum fluctuation
s play a crucial role. We suggest that for a certain range of parameters a
classical picture can be maintained. This involves identifying ultra-viol
et and infra-red cut offs whose value is induced by the parameters of the
potential. In the presence of these cutoffs one of Coleman's boundary cond
ition needs to be reconsidered. This allows to obtain a new class of O(N)
invariant solutions which lead to acceptable results for the decay constan
t of the false vacuum.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Tong (Cambridge University)
DTSTART:20201208T110000Z
DTEND:20201208T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/28
DESCRIPTION:Title: Comments on Chiral Fermions\nby David Tong (Cambridge University) as
part of CCTP HEP Seminars\n\n\nAbstract\nA well known piece of folklore s
ays that it's not possible to give fermions in a chiral gauge theory a mas
s without breaking the gauge symmetry. This folklore is wrong. I'll demons
trate this by showing how to give one generation of fermions in the Standa
rd Model a mass without breaking electroweak symmetry.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Myers (Perimeter Institute)
DTSTART:20201215T150000Z
DTEND:20201215T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/29
DESCRIPTION:Title: Quantum Extremal Islands Made Easy\nby Robert Myers (Perimeter Insti
tute) as part of CCTP HEP Seminars\n\n\nAbstract\nWe illustrate the appear
ance of quantum extremal islands in holographic setups in higher dimension
s. We emphasize the close parallel with the behaviour of holographic entan
glement entropy in more familiar settings.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Blaise Gouteraux (École Polytechnique)
DTSTART:20210108T110000Z
DTEND:20210108T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/30
DESCRIPTION:Title: Hydrodynamic diffusion and its breakdown near AdS2 fixed points\nby
Blaise Gouteraux (École Polytechnique) as part of CCTP HEP Seminars\n\n\n
Abstract\nHydrodynamics provides a universal description of interacting qu
antum field theories at sufficiently long times and wavelengths\, but brea
ks down at scales dependent on microscopic details of the theory. We use g
auge-gravity duality to investigate the breakdown of diffusive hydrodynami
cs in two low temperature states dual to black holes with AdS2 horizons. W
e find that the breakdown is characterized by a collision between the diff
usive pole of the retarded Green's function with a pole associated to the
AdS2 region of the geometry\, such that the local equilibration time is se
t by infra-red properties of the theory. The absolute values of the freque
ncy and wavevector at the collision (ωeq and keq) provide a natural chara
cterization of all the low temperature diffusivities D of the states via D
=ωeq/keq^2 where ωeq=2πΔT is set by the temperature T and the scaling
dimension Δ of an infra-red operator. We confirm that these relations are
also satisfied in an SYK chain model in the limit of strong interactions.
\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ben Craps (VUB)
DTSTART:20210112T110000Z
DTEND:20210112T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/31
DESCRIPTION:Title: Slow scrambling in extremal BTZ and microstate geometries\nby Ben Cr
aps (VUB) as part of CCTP HEP Seminars\n\n\nAbstract\nOut-of-time-order co
rrelators (OTOCs) that capture maximally chaotic properties of a black hol
e are determined by scattering processes near the horizon. This prompts th
e question to what extent OTOCs display chaotic behaviour in horizonless m
icrostate geometries. This question is complicated by the fact that Lyapun
ov growth of OTOCs requires nonzero temperature\, whereas constructions of
microstate geometries have been mostly restricted to extremal black holes
. We compute OTOCs for a class of extremal black holes\, namely maximally
rotating BTZ black holes\, and show that on average they display "slow scr
ambling"\, characterized by cubic (rather than exponential) growth. Superp
osed on this average power-law growth is a sawtooth pattern\, whose steep
parts correspond to brief periods of Lyapunov growth associated to the non
zero temperature of the right-moving degrees of freedom in a dual conforma
l field theory. Next we study the extent to which these OTOCs are modified
in certain "superstrata"\, horizonless microstate geometries correspondin
g to these black holes. Rather than an infinite throat ending on a horizon
\, these geometries have a very deep but finite throat ending in a cap. We
find that the superstrata display the same slow scrambling as maximally r
otating BTZ black holes\, except that for large enough time intervals the
growth of the OTOC is cut off by effects related to the cap region\, some
of which we evaluate explicitly.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wilke van der Schee (CERN)
DTSTART:20210119T110000Z
DTEND:20210119T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/32
DESCRIPTION:Title: Entanglement entropy in expanding spacetimes\nby Wilke van der Schee
(CERN) as part of CCTP HEP Seminars\n\n\nAbstract\nThis talk will be abou
t entanglement entropy in empty 4-dimensional de Sitter spacetime of a non
-conformal QFT [2011.08194]. I will first briefly describe the set-up and
show how a hydrodynamic plasma dilutes and falls out of equilibrium due to
expansion towards empty de Sitter spacetime. We track the evolutions of t
he event and apparent horizons\, showing in particular that the temperatur
e of the event horizon approaches the de Sitter temperature. Interestingly
\, in the empty setting we can show that extremal surfaces in the holograp
hic dual of spherical entangling regions on the boundary QFT probe beyond
the dual event horizon if and only if the entangling region is larger than
the cosmological horizon.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Penedones (EPFL)
DTSTART:20210126T110000Z
DTEND:20210126T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/33
DESCRIPTION:Title: Bootstrapping Quantum Field Theories\nby Joao Penedones (EPFL) as pa
rt of CCTP HEP Seminars\n\n\nAbstract\nI will review the recent revival of
the S-matrix Bootstrap program. In particular\, I will discuss the formul
ation that includes scattering amplitudes\, form factors and spectral dens
ities.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dieter Lust (Max-Planck Institute)
DTSTART:20210202T110000Z
DTEND:20210202T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/34
DESCRIPTION:Title: The swampland at large number of space-time dimensions\nby Dieter Lu
st (Max-Planck Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nWe d
iscuss some aspects of swampland constraints - especially the swampland di
stance conjecture - in a large number of space-time dimensions D. We analy
ze Kaluza-Klein (KK) states at large D and find that some KK spectra posse
ss an interesting dependence on D. On the basis of these observations we p
ropose a new large dimension conjecture. We apply it to KK states of compa
ctifications to anti-de Sitter backgrounds where it predicts an upper boun
d on the dimension of space-time as a function of its characteristic radiu
s. We also apply our conjecture to black hole spacetimes\, whose entropies
have a D-dependence very similar to that of the KK spectrum.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Georgoudis (IPhT Saclay)
DTSTART:20210330T100000Z
DTEND:20210330T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/35
DESCRIPTION:Title: Supergravity Amplitudes on AdS5×S5 and their flat-space limit\nby A
lessandro Georgoudis (IPhT Saclay) as part of CCTP HEP Seminars\n\n\nAbstr
act\nWe will study the four point function of the superconformal primary o
f the stress-tensor multiplet in four dimensional N=4 Super Yang Mills\, a
t large 't Hooft coupling and in a large N expansion. This observable is h
olographically dual to four graviton amplitudes in type IIB supergravity o
n AdS5×S5. We first will construct the most trascendental piece of the co
rrelator at any order in a large N expansion. They are determined only by
leading order CFT data. By focusing on a specific limit\, we make connecti
on with the dual supergravity amplitude in flat space\, where such structu
res correspond to iterated s-cuts. We make several checks and we conjectur
e that the same interpretation holds for supergravity amplitudes on AdS5×
S5.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgi Dvali (Max Planck Institute)
DTSTART:20210209T110000Z
DTEND:20210209T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/36
DESCRIPTION:Title: S-matrix constraints on de Sitter and on black holes\nby Georgi Dval
i (Max Planck Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nWe di
scuss how the S-matrix formulation of quantum gravity/string theory exclud
es any sort of stable or a metastable de Sitter. The constraint is enforce
d by the phenomenon of quantum break-time. This has a number of observable
consequences both for early and late cosmology. In particular\, it exclud
es cosmological constant as part of the energy budget in the Universe. We
confront the quantum portraits of de Sitter and black holes and point out
similarities as well as fundamental differences.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bzowski (UOC)
DTSTART:20210216T110000Z
DTEND:20210216T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/37
DESCRIPTION:Title: Consistency of supersymmetric 't Hooft anomalies\nby Adam Bzowski (U
OC) as part of CCTP HEP Seminars\n\n\nAbstract\nWe consider recent claims
that supersymmetry is anomalous in the presence of a R-symmetry anomaly. W
e revisit arguments that such an anomaly in supersymmetry can be removed a
nd write down an explicit counterterm that accomplishes it. Removal of the
supersymmetry anomaly requires enlarging the corresponding current multip
let. As a consequence the Ward identities for other symmetries that are al
ready anomalous acquire extra terms. This procedure can only be impeded wh
en the choice of current multiplet is forced. We show how Wess-Zumino cons
istency conditions are modified when the anomaly is removed. Finally we ch
eck that the modified Wess-Zumino consistency conditions are satisfied\, a
nd supersymmetry unbroken\, in an explicit one loop computation using Paul
i-Villars regulators. To this end we comment on how to use Pauli-Villars t
o regulate correlators of components of (super)current multiplets in a man
ifestly supersymmetric way.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Jepsen (Stony Brook)
DTSTART:20210309T150000Z
DTEND:20210309T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/38
DESCRIPTION:Title: Tensor Models and Limit Cycles\nby Christian Jepsen (Stony Brook) as
part of CCTP HEP Seminars\n\n\nAbstract\nMatrix and tensor models with U(
N) or O(N) symmetry offer a surprise on analytic continuation in N: the ex
istence of fixed points of the beta functions where the the coupling const
ants gi are real but the scaling dimensions\, as determined by the eigenva
lues of the Jacobian matrix ∂βi/∂gj\, are complex. When these complex
eigenvalues cross the imaginary axis\, a Hopf bifurcation takes place and
gives rise to a limit cycle in the RG flow. In this talk\, I will present
an overview of this phenomenon and present a number of examples.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikhail Shaposhnikov (EPFL Lausanne)
DTSTART:20210223T110000Z
DTEND:20210223T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/39
DESCRIPTION:Title: Einstein-Cartan gravity: Inflation\, Dark Matter and Electroweak Symmetr
y Breaking\nby Mikhail Shaposhnikov (EPFL Lausanne) as part of CCTP HE
P Seminars\n\n\nAbstract\nIt is well-known since the works of Utiyama and
Kibble that the gravitational force can be obtained by gauging the Lorentz
group\, which puts gravity on the same footing as the Standard Model fiel
ds. The resulting theory - Einstein-Cartan gravity - happens to be very in
teresting. First\, it incorporates Higgs inflation at energies below the o
nset of the strong-coupling of the theory. Second\, it contains a four-fer
mion interaction that originates from torsion associated with spin degrees
of freedom. This interaction leads to a novel universal mechanism for pro
ducing singlet fermions in the Early Universe. These fermions can play the
role of dark matter particles. Finally\, it may generate the electroweak
symmetry breaking by a non-perturbative gravitational effect.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter (Caltech)
DTSTART:20210316T110000Z
DTEND:20210316T120000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/40
DESCRIPTION:Title: A CFT Distance Conjecture\nby Eric Perlmutter (Caltech) as part of C
CTP HEP Seminars\n\n\nAbstract\nWe formulate conjectures relating the geom
etry of conformal manifolds to the spectrum of local operators in conforma
l field theories in d>2 spacetime dimensions. We focus on conformal manifo
lds with limiting points at infinite distance with respect to the Zamolodc
hikov metric. Our central conjecture is that all theories at infinite dist
ance possess an emergent higher-spin symmetry\, generated by an infinite t
ower of currents whose anomalous dimensions vanish exponentially in the di
stance. Our conjectures are related to the Distance Conjecture in the swam
pland program. We discuss the supporting evidence\, their holographic inte
rpretation\, and implications for superconformal field theories.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero (Harvard)
DTSTART:20210323T150000Z
DTEND:20210323T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/41
DESCRIPTION:Title: Chern-Weil global symmetries and completeness of the spectrum\nby Mi
guel Montero (Harvard) as part of CCTP HEP Seminars\n\n\nAbstract\nPerhaps
the oldest Swampland conjecture in the book is the absence of global symm
etries. I will describe the consequences of applying this conjecture to a
particular class of symmetries\, Chern-Weil symmetries\, that are ubiquito
us in string compactifications and which arise from powers of fieldstrengh
ts. I will explore the processes by which Chern-Weil symmetries may be bro
ken or gauged in effective field theory and string theory. This will allow
us to derive the existence of familiar features of string theory\, such a
s worldvolume degrees of freedom in branes. Another lore holds that absenc
e global symmetries in a quantum field theory is equivalent to having a co
mplete spectrum of charged states in the theory. I will discuss and make p
recise this connection\, and explain and how a particular version of it ca
n be proven in pure gauge theory with arbitrary (even disconnected) gauge
group.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Konstantinos Roumbedakis (Stony Brook)
DTSTART:20210406T150000Z
DTEND:20210406T160000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/42
DESCRIPTION:Title: Symmetries and Strings of adjoint QCD in two dimensions\nby Konstant
inos Roumbedakis (Stony Brook) as part of CCTP HEP Seminars\n\n\nAbstract\
nIn this talk\, we will review the notion of non-invertible symmetries and
we will study adjoint QCD in two dimensions. It turns out that this theor
y has a plethora of such symmetries which require deconfinement in the mas
sless case. When a mass or certain quartic interactions are tunrned on\, t
hese symmetries are broken and the theory confines. In addition\, we will
use these symmetries to calculate the string tension for small mass and ma
ke some comments about naturalness along the RG flow.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Karananas (Munich)
DTSTART:20210413T100000Z
DTEND:20210413T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/43
DESCRIPTION:Title: Spontaneous Conformal Symmetry Breaking in the Fishnet CFT\nby Georg
ios Karananas (Munich) as part of CCTP HEP Seminars\n\n\nAbstract\nQuantum
field theories with exact but spontaneously broken conformal invariance h
ave an intriguing feature: their vacuum energy is equal to zero. Up to now
\, the only known ultraviolet complete theories where conformal symmetry c
an be spontaneously broken were associated with supersymmetry\, with the m
ost prominent example being the N =4 SYM. Interestingly\, its non-supersym
metric descendant\, the "Fishnet theory\," supports at the classical level
a rich set of flat directions along which conformal symmetry is spontaneo
usly broken. At least perturbatively\, some of these vacua survive in the
full quantum theory - in the planar limit - without any finetuning. As a r
esult\, the vacuum energy vanishes along these flat directions\, providing
the first non-supersymmetric example of a four-dimensional quantum field
theory with "natural" breaking of conformal symmetry.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Papathanasiou (DESY)
DTSTART:20210504T100000Z
DTEND:20210504T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/44
DESCRIPTION:Title: Cluster Algebras for Feynman Integrals\nby Georgios Papathanasiou (D
ESY) as part of CCTP HEP Seminars\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Riccardo Rattazzi (EPFL)
DTSTART:20210511T100000Z
DTEND:20210511T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/45
DESCRIPTION:Title: The quantum mechanics of a perfect fluid\nby Riccardo Rattazzi (EPFL
) as part of CCTP HEP Seminars\n\n\nAbstract\nFinite density systems can b
e described by effective field\ntheories with non-linearly realized space-
time symmetries\,\nwhose construction resembles that of the QCD chiral lag
rangian. Also\nbased on that similarity\, one would expect the\nconstructi
on to work equally well classically and quantum mechanically.\nWhile that
is true for superfluids and solids\,\none instead finds that for genuine f
luids things are made more\ncomplicated by the unusual dynamics of their t
ransverse\nmodes\, which are not described by a Fock space. Focussing on
the\nincompressible limit in 2+1 dimensions\, I illustrate how a consisten
t\nquantum mechanical description of a perfect fluid can be obtained by\nu
sing the known equivalence between the area preserving diffeomorfism \ngr
oup in 2D and $SU(N)$ with $N\\to \\infty$.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shiraz Minwalla (TIFR)
DTSTART:20210420T100000Z
DTEND:20210420T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/46
DESCRIPTION:by Shiraz Minwalla (TIFR) as part of CCTP HEP Seminars\n\nAbst
ract: TBA\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gui Pimentel (Amsterdam)
DTSTART:20210427T130000Z
DTEND:20210427T140000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/47
DESCRIPTION:Title: Decoding and bootstrapping cosmological fluctuations\nby Gui Pimente
l (Amsterdam) as part of CCTP HEP Seminars\n\n\nAbstract\nI will review ou
r current understanding of the initial conditions of the universe\, and de
scribe what information is available from current and future measurements
of cosmological correlation functions. Then I will describe a new method t
o compute and constrain the possible shapes of those correlation functions
\, assuming they were generated during inflation. This ``cosmological boot
strap" draws inspiration from the modern scattering amplitudes program in
flat space\, as well as the conformal bootstrap of phase transitions. Afte
r discussing primordial scalar fluctuations\, I will also explain how the
consistent propagation of gravitational waves imposes further constraints
on the structure of spinning primordial correlators.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Zhiboedov (CERN)
DTSTART:20210518T100000Z
DTEND:20210518T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/49
DESCRIPTION:Title: Probing gravitational EFTs with the four-graviton amplitude\nby Alex
ander Zhiboedov (CERN) as part of CCTP HEP Seminars\n\n\nAbstract\nWe disc
uss constraints from perturbative unitarity and\ncrossing on the leading c
ontributions of the higher-dimension operators\nto the four-graviton ampli
tude in four spacetime dimensions. We focus on\nthe leading order effect d
ue to exchange by massive degrees of freedom\nwhich makes the amplitudes o
f interest IR finite. To test the\nconstraints we obtain nontrivial effect
ive field theory data by\ncomputing and taking the large mass expansion of
the one-loop\nminimally-coupled four-graviton amplitude with massive part
icles up to\nspin 2 circulating in the loop. Remarkably\, the leading EFT
corrections\nto Einstein gravity of physical theories\, both string theory
and QFT\ncoupled to gravity\, end up in minuscule islands which are much
smaller\nthan what is suggested by the generic bounds obtained from consis
tency\nof the 2-2 graviton scattering amplitude. We discuss the underlying
\nmechanism for this phenomenon.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pawel Caputa (Warsaw)
DTSTART:20210525T100000Z
DTEND:20210525T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/50
DESCRIPTION:Title: Holographic Path Integral Optimization\nby Pawel Caputa (Warsaw) as
part of CCTP HEP Seminars\n\n\nAbstract\nI will talk about recent work on
understanding path integral optimization in CFTs holographically using Har
tle-Hawking wave functions in AdS. The talk will be based on arXiv: 2011.0
8188 [hep-th] and 2104.00010 [hep-th].\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Victor Gorbenko (Stanford)
DTSTART:20210601T100000Z
DTEND:20210601T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/51
DESCRIPTION:Title: Bra-ket wormholes in gravitationally prepared states\nby Victor Gorb
enko (Stanford) as part of CCTP HEP Seminars\n\n\nAbstract\nWe will discus
s two-dimensional toy-models of inflation in which the state of the univer
se is prepared by a gravitational path integral. As a first model\, we con
sider a state produced by Euclidean AdS_2 evolution followed by flat space
evolution. We use the fine grained entropy formula to explore the nature
of the state. We find that the naive hyperbolic space geometry (analog of
the Hartle-Hawking state) leads to a paradox. This is solved if we include
a geometry that connects the bra with the ket\, a bra-ket wormhole. The s
emiclassical Lorentzian interpretation leads to CFT state entangled with a
n expanding and collapsing Friedmann cosmology. I will then describe a sim
ilar model where the state is prepared by the dS_2 evolution and highlight
related puzzles.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Enrico Pajer (Cambridge)
DTSTART:20210608T100000Z
DTEND:20210608T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/52
DESCRIPTION:Title: A Timeless History of Time\nby Enrico Pajer (Cambridge) as part of C
CTP HEP Seminars\n\n\nAbstract\nCosmological observations give us the uniq
ue opportunity to\nprobe the fundamental laws of physics at very high ener
gies as well as\nthe perturbative regime of quantum gravity. Unfortunately
\, due to the\ncreativity of theorists and the paucity of data about the p
rimordial\nuniverse\, there is a huge number of models compatible with all
\nmeasurements\, featuring a wide variety of mechanisms\, symmetries\, and
\nspectra of particles.The reason can be traced back to the fact that we\n
don't observe the time evolution during inflation\, but only its final\nou
tcome.\n\nIn this talk I will report on the recent progress in developing
a\ncompletely new "bootstrap" approach to derive predictions from the very
\nearly universe that make no reference to time and the un-observable time
\nevolution. The bootstrap approach builds directly upon the fundamental\n
pillars of physics. In particular\, I will present the recent\nbreakthroug
hs in understanding the consequence of unitarity for\ncosmological correla
tors to all orders in perturbation theory\, as well\nas the footprint of (
bulk) locality. I will show how these principles\ncan be used to derive ma
ny classical and new inflationary predictions\nassociated with primordial
non-Gaussianity in a way that is both\ncomputationally simpler and concept
ually more transparent. This includes\na reconstruction formula that relat
es de Sitter correlators to\namplitudes for massless particles\, cosmologi
cal partial-energy recursion\nrelations and a "timeless" differential repr
esentation of the\nperturbative wavefunction. This approach makes no refer
ence to de Sitter\nboosts\, which are broken by a large amount in models t
hat predict large\nnon-Gaussianity.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kostas Skenderis (Southampton)
DTSTART:20210615T100000Z
DTEND:20210615T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/53
DESCRIPTION:Title: Holographic cosmology and the origin of time\nby Kostas Skenderis (S
outhampton) as part of CCTP HEP Seminars\n\n\nAbstract\nHolographic cosmol
ogy is a new framework for the very early universe\, the period usually as
sociated with inflation. In holographic cosmology the early Universe is de
scribed by a three dimensional QFT\, and cosmological evolution is mapped
to inverse RG flow. In this talk\, I will provide an overview of holograph
ic cosmology and then discuss recent work where lattice QFT methods are us
ed to compute the relevant QFT observables. In particular\, I will discuss
the IR structure of the dual QFT\, which is linked to the initial singula
rity in cosmology\, and show how non-perturbative dynamics resolve the IR
singularities present in perturbation theory\, thus providing a holographi
c resolution of the Big Bang singularity.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dam Son (Chicago)
DTSTART:20210622T140000Z
DTEND:20210622T150000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/54
DESCRIPTION:Title: Volume preserving diffeomorphism as a higher-rank gauge symmetry\nby
Dam Son (Chicago) as part of CCTP HEP Seminars\n\n\nAbstract\nRecently\,
theories with higher rank gauge symmetries are drawing attention in conden
sed matter physics. Such theories are thought to be related to the so-call
ed "fractons\," quasiparticles with limited mobility that appear in some l
attice models. We show that one version of such higher ranked symmetry can
be "nonlinearlized" into volume-preserving diffeomorphism. We demonstrate
that several condensed matter systems\, including the fractional quantum
Hall effect and ferromagnetism\, secretly possess this symmetry\, which sh
eds another light to some peculiar features of the quasiparticles in these
systems.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioanna Kourkoulou (Columbia)
DTSTART:20210629T140000Z
DTEND:20210629T150000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/55
DESCRIPTION:Title: Lorentz invariance in Framids as a potential technical analog of the CCP
\nby Ioanna Kourkoulou (Columbia) as part of CCTP HEP Seminars\n\n\nAb
stract\nThe Framid is a hypothetical system whose ground state\nspontaneou
sly breaks boost symmetry\, however its stress-energy tensor\nretains a Lo
rentz-invariant expectation value on the ground state\, as we\nverify expl
icitly to one-loop order. The mechanism enforcing this result\nis rather o
bscure\; in fact\, we think this puzzle is an interesting\ntechnical analo
g of the cosmological constant problem. I will describe\nour computations
that verify the Lorentz invariance of the expectation\nvalue in question\,
and how these yield the expected result only thanks\nto highly nontrivial
cancellations\, which are quite mysterious from the\nlow-energy effective
theory viewpoint.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Rizos (Ioannina U.)
DTSTART:20210706T100000Z
DTEND:20210706T110000Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/56
DESCRIPTION:Title: On nonsupersymmetric string models and the decompactification problem\nby John Rizos (Ioannina U.) as part of CCTP HEP Seminars\n\n\nAbstract\
nWe study 4d heterotic string compactifications exhibiting\nspontaneous su
persymmetry breaking via the Scherk–Schwarz mechanism\nassociated with t
wo large internal dimensions. We identify a class of\nmodels with fermion
–boson degeneracy that address some central issues in\nnonsupersymmetric
string phenomenology including the elimination of\ntachyons and dilaton t
adpoles and the suppression of the cosmological\nconstant. In addition\, w
e propose a novel solution to the\ndecompactification problem related to t
he cancellation of the linear\ngrowth of the gauge part of the thresholds
with a similar growth of the\nuniversal part.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dimitrios Patramanis (Warsaw)
DTSTART:20210727T101500Z
DTEND:20210727T111500Z
DTSTAMP:20260513T182056Z
UID:CCTP_HEP/57
DESCRIPTION:Title: A geometric perspective on the holographic Berry phase\nby Dimitrios
Patramanis (Warsaw) as part of CCTP HEP Seminars\n\n\nAbstract\nAfter bri
efly reviewing the notions of Berry's phase and\ncoadjoint orbits I will b
e explaining how these arise in a holographic\nsetup. Namely\, I will be t
alking about the modular Berry phase arising\nin AdS3/CFT2 and the prospec
ts of its generalization in the broader\ncontext of the Banados geometries
. To this end I will be discussing the\ndifferent tools and methods requir
ed to do so and attempt to highlight\ntheir utility in addressing both que
stions in holography and problems of\na more general nature.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/57/
END:VEVENT
END:VCALENDAR