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BEGIN:VEVENT
SUMMARY:Aristomenis Donos (Durham University)
DTSTART:20200512T111500Z
DTEND:20200512T121500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/1
DESCRIPTION:Title: Vortex Lattices From Holography\nby Aristomenis Donos (Durham
University) as part of CCTP HEP Seminars\n\n\nAbstract\nVortices are fasci
nating stable configurations of electric currents that occur in the broken
phase of superconductors. Based on an effective field theory approach\, A
brikosov argued that when the force between them is repulsive\, stable per
iodic configurations can form. In my talk I will consider similar construc
tions for superfluids away from the critical temperature. Moreover\, I wil
l discuss how known field theories can exhibit phases which are not captur
ed by Abrikosov's considerations.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dimitrios Giataganas (NKUA)
DTSTART:20200519T111500Z
DTEND:20200519T121500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/2
DESCRIPTION:Title: Anisotropic holography\nby Dimitrios Giataganas (NKUA) as part
of CCTP HEP Seminars\n\n\nAbstract\nStrongly coupled anisotropic systems
have significantly richer structure than the isotropic ones. This is espec
ially evident in the transport coefficients and in the phase diagram of an
isotropic theories. We discuss such holographic theories\, we comment on t
heir observables and demonstrate how the isotropic universal relations are
violated in presence of anisotropies. We also propose c-function candidat
es for the anisotropic RG flows and show that their monotonicity is not an
y more guaranteed by the energy conditions but depends on the theory chara
cteristics.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Achilleas Porfyriadis (Harvard University)
DTSTART:20200526T131500Z
DTEND:20200526T141500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/3
DESCRIPTION:Title: The connection problem for AdS2\nby Achilleas Porfyriadis (Har
vard University) as part of CCTP HEP Seminars\n\n\nAbstract\nI will talk a
bout the problem of extending anti-de Sitter solutions away from the near-
horizon region of (near-)extreme black holes and connecting them with solu
tions in the black holes far asymptotically flat region. In Part I of the
talk I will present analytic solutions to the connection problem for coupl
ed gravitational and electromagnetic perturbations of AdS2xS2 and near-AdS
2xS2 in the extreme and near-extreme Reissner-Nordstrom black holes\, resp
ectively. In Part II of the talk I will discuss a calculation of backreact
ion in AdS2. In this calculation\, an AdS2xS2 throat geometry reacts to a
perturbation by a scalar field in such a way that\, with leaky boundary co
nditions\, it maintains its connection to the far asymptotically flat regi
on of the black hole.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefanos Kousvos (UOC)
DTSTART:20200528T111500Z
DTEND:20200528T121500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/4
DESCRIPTION:Title: Bootstrapping theories with $O(m)\\times O(n)$ global symmetry in
three dimensions\nby Stefanos Kousvos (UOC) as part of CCTP HEP Semina
rs\n\n\nAbstract\nI will discuss recent work performed with Johan Henrikss
on and Andreas Stergiou studying O(m)xO(n) conformal field theories in thr
ee dimensions. Motivated by phase transitions in three-dimensional systems
\, as well as open theoretical questions\, we will focus on the $O(2)\\tim
es O(n)$ case. We study different values of $n$\, for $n$ sufficiently lar
ge we find excellent agreement with large $n$ predictions for scaling dime
nsions of operators. For $n=3$ we find closed isolated regions (islands) i
n parameter space that do not correspond to the ordinary fixed points of t
he $d=4-e$ expansion\, we attribute these regions of parameter space to fi
xed points conjectured to arise due to resummations of perturbative beta f
unctions.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jelle Hartong (University of Edinburg)
DTSTART:20200602T101500Z
DTEND:20200602T111500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/5
DESCRIPTION:Title: Dynamics of Fluids without Boost Symmetries\nby Jelle Hartong
(University of Edinburg) as part of CCTP HEP Seminars\n\n\nAbstract\nStand
ard textbook treatments of fluid dynamics assume the presence of a boost s
ymmetry. This is either a Galilean boost symmetry or a Lorentzian one and
leads to the Navier-Stokes equations or their relativistic counterpart. It
is however not necessary to rely on a boost symmetry as one can treat vel
ocity as the chemical potential associated with momentum conservation. In
fact for fluids moving through a medium one expects boost symmetries to be
generically broken. This includes the case of scale invariant Lifshitz fl
uids. In 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 non-dissipative transport coefficients (of which 2 are hydrostatic a
nd 4 are not) for uncharged non-boost invariant fluid dynamics. Time permi
tting\, I will discuss some general ideas regarding holographic realisatio
ns of non-boost invariant Lifshitz fluids.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mihalis Dafermos (Cambridge and Princeton University)
DTSTART:20200609T101500Z
DTEND:20200609T111500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/6
DESCRIPTION:Title: Strong Cosmic Censorship versus Λ\nby Mihalis Dafermos (Cambr
idge and Princeton University) as part of CCTP HEP Seminars\n\n\nAbstract\
nThe strong cosmic censorship conjecture is a fundamental open problem in
classical general relativity\, first put forth by Roger Penrose in the ear
ly 70s. This is essentially the question of whether general relativity is
a deterministic theory. Perhaps the most exciting arena where the validity
of the conjecture is challenged is the interior of rotating black holes\,
and there has been a lot of work in the past 50 years in identifying mech
anisms ensuring that at least some formulation of the conjecture be true.
It turns out that when a nonzero cosmological constant Λ is added to the
Einstein equations\, these underlying mechanisms change in an unexpected w
ay\, and the validity of the conjecture depends on a detailed understandin
g of subtle aspects of black hole scattering theory\, surprisingly involvi
ng\, in the case of negative Λ\, some number theory. Does strong cosmic c
ensorship survive the challenge of non-zero Λ? This talk will try to addr
ess this Question!\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Van Raamsdonk (University of British Columbia)
DTSTART:20200623T160000Z
DTEND:20200623T170000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/7
DESCRIPTION:Title: The holographic CFT masquerade\nby Mark Van Raamsdonk (Univers
ity of British Columbia) as part of CCTP HEP Seminars\n\n\nAbstract\nWe ar
gue that given holographic CFT1 in some state with a dual spacetime geomet
ry M\, and given some other holographic CFT2\, we can find states of CFT2
whose dual geometries closely approximate arbitrarily large causal patches
of M\, provided that CFT1 and CFT2 can be non-trivially coupled at an int
erface. Our CFT2 states are ``dressed up as'' states of CFT1: they are obt
ained from the original CFT1 state by a regularized quench operator define
d using a Euclidean path-integral with an interface between CFT2 and CFT1.
Our results are consistent with the idea that the precise microscopic deg
rees of freedom and Hamiltonian of a holographic CFT are only important in
fixing the asymptotic behavior of a dual spacetime\, while the interior s
pacetime of a region spacelike separated from a boundary time slice is det
ermined by more universal properties (such as entanglement structure) of t
he quantum state at this time slice. Our picture requires that low-energy
gravitational theories related to CFTs that can be non-trivially coupled a
t an interface are part of the same non-perturbative theory of quantum gra
vity.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Moschidis (University of California Berkeley)
DTSTART:20200630T101500Z
DTEND:20200630T111500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/8
DESCRIPTION:Title: The instability of Anti-de Sitter spacetime\nby Georgios Mosch
idis (University of California Berkeley) as part of CCTP HEP Seminars\n\n\
nAbstract\nAccording to the AdS instability conjecture\, there exist arbit
rarily small perturbations to the initial data of AdS spacetime which\, un
der evolution by the vacuum Einstein equations with reflecting boundary co
nditions on conformal infinity\, lead to the formation of black holes afte
r sufficiently long time. To this day\, the question about the vacuum equa
tions remains open (and poorly understood). However\, during the last deca
de\, a large number of numerical and heuristic works have been dedicated t
o addressing the conjecture in the presence of matter fields allowing sphe
rically symmetric dynamics. In this talk\, I will review the progress achi
eved so far in addressing the AdS instability conjecture and I will presen
t a rigorous proof of the instability in the setting of the spherically sy
mmetric Einstein--scalar field system. The proof will be based on the non-
linear interactions of special configurations of matter beams. The possibl
e extension of the main ideas to the vacuum case will also be discussed.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Panagiotis Betzios (University of Crete)
DTSTART:20200702T101500Z
DTEND:20200702T111500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/9
DESCRIPTION:Title: Liouville theory and Matrix models - A Wheeler DeWitt perspective<
/a>\nby Panagiotis Betzios (University of Crete) as part of CCTP HEP Semin
ars\n\n\nAbstract\nWe analyse the connections between the Wheeler DeWitt a
pproach for two dimensional quantum gravity and holography\, focusing main
ly in the case of Liouville theory coupled to c = 1 matter. Our motivation
is to understand whether some form of averaging is essential for the boun
dary theory\, if we wish to describe the bulk quantum gravity path integra
l of this two dimensional example. The analysis hence\, is in a spirit sim
ilar to the recent studies of Jackiw-Teitelboim (JT)-gravity. Macroscopic
loop operators define the asymptotic region on which the holographic bound
ary dual is expected to reside. Matrix quantum mechanics (MQM) and the ass
ociated double scaled fermionic field theory on the contrary\, is providin
g an explicit "unitary in superspace" description of the complete dynamics
of such two dimensional universes with matter\, including the effects of
topology change. If we try to associate a Hilbert space to a single bounda
ry dual\, it seems that it cannot contain all the information present in t
he non-perturbative bulk quantum gravity path integral and MQM.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constantin Bachas (ENS Paris)
DTSTART:20200714T100000Z
DTEND:20200714T110000Z
DTSTAMP:20260404T110915Z
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 desc
ribe the first gravitational calculation of the universal energy transmiss
ion and reflection coefficients of 2D conformal interfaces with holographi
c duals. The result is a monotonic function of the dual brane tension. It
is consistent with the ANEC bound (which is stricter than the positivity b
ound in the Euclidean theory).\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bzowski (University of Crete)
DTSTART:20200908T100000Z
DTEND:20200908T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/11
DESCRIPTION:Title: Toy models for AdS black holes\nby Adam Bzowski (University o
f Crete) as part of CCTP HEP Seminars\n\n\nAbstract\nI will present two si
mple toy models exhibiting properties associated with quantum black holes.
For the first model I will consider a quantum mechanical system of the do
uble well potential. The second model is obtained by coupling stress tenso
rs of the two CFTs living on the boundaries of the BTZ black hole. The com
mon theme of both systems is that the Hilbert space of states does not adm
it the usual factorization into a tensor product. Instead\, the semi-class
ical\, low-energy physics is emergent and can be reinterpreted in terms of
state-dependence.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Domenico Orlando (University of Torino)
DTSTART:20200915T100000Z
DTEND:20200915T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/12
DESCRIPTION:Title: Introduction to the large charge expansion\nby Domenico Orlan
do (University of Torino) as part of CCTP HEP Seminars\n\n\nAbstract\nWork
ing in sectors of large global charge leads to important simplifications w
hen studying strongly coupled CFTs. In this talk I will introduce the larg
e-charge expansion via the simple example of the O(2) model and apply it i
n a number of other situations displaying a richer structure\, such as non
-Abelian vector models\, supersymmetric N=2 systems and asymptotically saf
e theories.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anatoly Dymarsky (University of Kentucky)
DTSTART:20200922T100000Z
DTEND:20200922T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/13
DESCRIPTION:Title: Quantum codes\, lattices\, and conformal field theories\nby A
natoly Dymarsky (University of Kentucky) as part of CCTP HEP Seminars\n\n\
nAbstract\nThere is a deep relation between classical error-correcting\nco
des\, Euclidean lattices\, and chiral 2d CFTs. We show this relation\nexte
nds to include quantum codes\, Lorentzian lattices\, and non-chiral\nCFTs.
The relation to quantum codes provides a simple way to solve\nmodular boo
tstrap constraints and identify interesting examples of\nconformal theorie
s. In particular we construct many examples of\nphysically distinct isospe
ctral theories\, examples of "would-be" CFT\npartition function -- non-hol
omorphic functions satisfying all\nconstraints of the modular bootstrap\,
yet not associated with any\nknown CFT\, and find theory with the maximal
spectral gap among all\nNarain CFTs with the central charge c=4. We also d
iscuss averaging\nover the ensemble of all CFTs associated with quantum co
des\, and its\npossible holographic interpretation. The talk is based on\n
arXiv:2009.01236 and arXiv:2009.01244.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioannis Matthaiakakis (Julius-Maximilians-Universitaet Wuerzburg)
DTSTART:20200924T100000Z
DTEND:20200924T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/14
DESCRIPTION:Title: Turbulent hydrodynamics in strongly correlated Kagome materials\nby Ioannis Matthaiakakis (Julius-Maximilians-Universitaet Wuerzburg) a
s part of CCTP HEP Seminars\n\n\nAbstract\nIn recent years a lot of intere
st has been directed towards realizing strongly-coupled electronic fluids.
This interest is partly because a stronger coupling enables the transitio
n to the hydrodynamic regime and partly because of the novel transport phe
nomena such a fluid promises. Strongly-coupled fluids are also a natural a
nd fertile ground for testing and refining our understanding of AdS/CFT an
d holography in general. In this talk\, I will first show that Kagome mate
rials with a relativistic spectrum are a compelling platform for realizing
strongly-coupled fluids. Then\, I will employ holography to estimate thei
r ratio of shear viscosity to entropy density. With that estimate at hand\
, I will finally argue that strongly-coupled Kagome fluids put for the fir
st time non-linear hydrodynamic phenomena such as turbulence within experi
mental reach.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andreas Stergiou (Los Alamos National Laboratory)
DTSTART:20201006T140000Z
DTEND:20201006T150000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/15
DESCRIPTION:Title: Uncovering the Structure of the ε Expansion\nby Andreas Ster
giou (Los Alamos National Laboratory) as part of CCTP HEP Seminars\n\n\nAb
stract\nThe ε expansion was invented almost 50 years ago and has been use
d extensively ever since to quantitatively describe critical phenomena. It
s most famous applications are found in theories involving scalar fields i
n 4−ε dimensions. In this talk\, we will be interested in the structure
of the ε expansion of scalar field theories and the fixed points that ca
n be obtained within it. Our motivation is based on the goal of classifyin
g conformal field theories in d=3 dimensions. We will describe recently di
scovered universal constraints obtained within the framework of the ε exp
ansion\, focusing mostly on the 4−ε case although 3−ε will also be d
iscussed. It will be shown that a “heavy handed" way to search for fixed
points yields a plethora of new fixed points that reveal aspects of the s
tructure of the ε expansion and suggest that a classification of conforma
l field theories in d=3 is likely to be very non trivial. (Based on arXiv:
1707.06165\, arXiv:1810.10541 and upcoming work with Hugh Osborn.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zohar Komargodski (Simons Center)
DTSTART:20201015T120000Z
DTEND:20201015T130000Z
DTSTAMP:20260404T110915Z
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 notion of extended symmetry and show how it can be applied for two di
mensional QCD. We will use extended symmetry to prove deconfinement and to
compute the exact string tension when the quarks are light. Some interest
ing implications for the naturalness of RG flows will be discussed as well
.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Warner (Southern California University)
DTSTART:20200929T100000Z
DTEND:20200929T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/17
DESCRIPTION:Title: Tidal Trapping of Strings by Microstate Geometries\nby Nick W
arner (Southern California University) as part of CCTP HEP Seminars\n\n\nA
bstract\nI will describe the fate of a massless (or ultra-relativistic mas
sive) string probe propagating down the BTZ-like throat of a microstate ge
ometry in the D1-D5 system. Far down the throat\, the probe encounters lar
ge tidal forces that stretch and excite the string. The excitations are li
mited by the very short transit time through the region of large tidal for
ce\, leading to a controlled approximation to tidal stretching. The amount
of stretching is proportional to the incident energy\, and that it robs t
he probe of the kinetic energy it would need to travel back up the throat.
As a consequence\, the probe is effectively trapped far down the throat a
nd\, through repeated return passes\, scrambles into the ensemble of nearb
y microstates. This tidal trapping can lead to weak gravitational echoes.\
n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shai Chester (Weizmann Institute)
DTSTART:20201020T100000Z
DTEND:20201020T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/18
DESCRIPTION:Title: AdS/CFT at Finite String Coupling\nby Shai Chester (Weizmann
Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nWe study the N = 4
SU(N) super-Yang-Mills stress tensor multiplet four-point function at larg
e N and finite complexified Yang-Mills coupling tau\, which is dual to th
e 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
integrated correlators obtained by taking various combinations of four der
ivatives of m\, b\, and tau of the sphere free energy deformed by mass m a
nd squashing parameter b\, which can be computed using supersymmetric loca
lization. We show that at each order in 1/N\, these quantities can be writ
ten in terms of modular invariants\, such as the well studied non-Holomorp
hic Eisenstein series as well as some new generalizations thereof. These r
esults reproduce known features of the low-energy expansion of the four-gr
aviton amplitude in type IIB superstring theory in ten-dimensional flat sp
ace\, which is the first check of AdS/CFT at finite string coupling\, and
have interesting implications for the structure of the analogous expansion
in AdS_5 × S^5.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ofer Aharony (Weizmann Institute)
DTSTART:20201027T120000Z
DTEND:20201027T130000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/19
DESCRIPTION:Title: Little String Theory on Curved Manifolds\nby Ofer Aharony (We
izmann Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nThis talk is
based on 1908.02642\, in collaboration with Evtikhiev and Feldman. After
reviewing Little String Theories (the decoupled theories on the worldvolum
e of N NS5-branes) we will use their holographic duality to Type II string
theory in asymptotically linear dilaton backgrounds in order to study the
se theories on curved space-times. We focus on backgrounds with a large nu
mber of Killing vectors (namely\, products of maximally symmetric spaces)\
, without requiring supersymmetry (we do not turn on any background fields
except the metric). Little String Theory is non-local so it is not obviou
s which spaces it can be defined on\; we show that holography implies that
the theory cannot be put on negatively curved spaces\, but only on spaces
with zero or positive curvature. For example\, one cannot put Little Stri
ng Theory on a product of an anti-de Sitter space times another space\, wi
thout turning on extra background fields. On spaces with positive curvatur
e\, such as products of spheres\, we typically find (for large N) dual hol
ographic backgrounds which are weakly coupled and weakly curved everywhere
\, so that they can be well-described by Type II supergravity. In some cas
es more than one smooth solution exists for Little String Theory on the sa
me space\, and they all contribute to the partition function. We also stud
y the thermodynamical properties of Little String Theory compactified on s
pheres\, finding the leading correction to the Hagedorn behavior of the sp
ectrum\, which is different on curved space than on flat space.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou (University of British Columbia)
DTSTART:20201106T150000Z
DTEND:20201106T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/20
DESCRIPTION:Title: Inside the Hologram: The bulk observer's experience\nby Lampr
os Lamprou (University of British Columbia) as part of CCTP HEP Seminars\n
\n\nAbstract\nI will present a holographic framework for reconstructing th
e experience of bulk observers in AdS/CFT. In particular\, I will show how
to recover the proper time and energy distribution measured along bulk wo
rldlines\, directly in the CFT via a universal\, background-independent pr
escription. For an observer falling into an eternal AdS black hole\, the p
roposal resolves a conceptual puzzle raised by Marolf and Wall. Notably\,
the prescription does not rely on an external dynamical Hamiltonian or the
AdS boundary conditions and is\, therefore\, outlining a general framewor
k for the emergence of time\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Meltzer (Caltech)
DTSTART:20201013T140000Z
DTEND:20201013T150000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/23
DESCRIPTION:Title: The Inversion Formula and 3d CFTs\nby David Meltzer (Caltech)
as part of CCTP HEP Seminars\n\n\nAbstract\nThe Lorentzian inversion form
ula proves that CFT data is analytic in spin and that operators can be org
anized on Regge trajectories. In this talk we investigate the leading Regg
e trajectories of the O(2) model using a combination of numerical and anal
ytical techniques. We find agreement between the two methods in various ch
arge sectors of the O(2) CFT. Furthermore\, we find evidence that scalar o
perators lie on Regge trajectories and estimate the Regge intercept of the
O(2) model. Finally\, we use the analytic and numerical data to study non
-Gaussianities in the charge-1 scalar four-point function.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexey Milekhin (Princeton University)
DTSTART:20201110T150000Z
DTEND:20201110T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/24
DESCRIPTION:Title: Humanly Traversable Wormholes\nby Alexey Milekhin (Princeton
University) as part of CCTP HEP Seminars\n\n\nAbstract\nIn my talk I will
present the construction of humanly traversable wormholes in four dimensio
ns. The construction is based on two magnetically charged black holes embe
dded into Randall-Sundrum model. In particular\, it does not need exotic m
atter or boundary conditions. It is a long wormhole that does not lead to
causality violations in the ambient space. I will explain why it is humanl
y traversable and what could be the challenges for the travelling observer
.\nThe talk is based on arxiv.org/abs/2008.06618\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simon Caron Huot (McGill)
DTSTART:20201117T140000Z
DTEND:20201117T150000Z
DTSTAMP:20260404T110915Z
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 state
ments of causality. They give sum rules connecting infrared and ultraviole
t physics. While they originate in optics and quantum field theory\, I wi
ll argue that their 'true purpose' is gravity\, viewed as a low-energy eff
ective theory. This is due to the unique energy dependence of this force.
I will present ongoing work mapping out the space of consistent effective
theories\, including recent results in scalar models (2011.02957)\, deriv
ing a sharp version of dimensional analysis scaling from causality.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stefanos Aretakis (University of Toronto)
DTSTART:20201124T150000Z
DTEND:20201124T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/26
DESCRIPTION:Title: Asymptotics for the wave equation on black hole spacetimes\nb
y Stefanos Aretakis (University of Toronto) as part of CCTP HEP Seminars\n
\n\nAbstract\nWe will present the precise late-time asymptotics for scalar
fields on both extremal and sub-extremal black holes including the full R
eissner-Nordstrom family and the subextremal Kerr family. Asymptotics for
higher angular modes will be presented for all cases. Applications in obse
rvational signatures will also be discussed. This work is joint with Y. An
gelopoulos (Caltech) and D. Gajic (Cambridge)\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eliezer Rabinovici (Hebrew University of Jerusalem)
DTSTART:20201201T110000Z
DTEND:20201201T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/27
DESCRIPTION:Title: Quantum fluctuations and instantons\nby Eliezer Rabinovici (H
ebrew University 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
consider the decay involved in circumstances where the methods suggested
by Coleman run into difficulties. We find that in those cases quantum fluc
tuations play a crucial role. We suggest that for a certain range of param
eters a classical picture can be maintained. This involves identifying ult
ra-violet 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 bounda
ry condition needs to be reconsidered. This allows to obtain a new class o
f O(N) invariant solutions which lead to acceptable results for the decay
constant of the false vacuum.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Tong (Cambridge University)
DTSTART:20201208T110000Z
DTEND:20201208T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/28
DESCRIPTION:Title: Comments on Chiral Fermions\nby David Tong (Cambridge Univers
ity) as part of CCTP HEP Seminars\n\n\nAbstract\nA well known piece of fol
klore says that it's not possible to give fermions in a chiral gauge theor
y a mass without breaking the gauge symmetry. This folklore is wrong. I'll
demonstrate this by showing how to give one generation of fermions in the
Standard Model a mass without breaking electroweak symmetry.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robert Myers (Perimeter Institute)
DTSTART:20201215T150000Z
DTEND:20201215T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/29
DESCRIPTION:Title: Quantum Extremal Islands Made Easy\nby Robert Myers (Perimete
r Institute) as part of CCTP HEP Seminars\n\n\nAbstract\nWe illustrate the
appearance of quantum extremal islands in holographic setups in higher di
mensions. We emphasize the close parallel with the behaviour of holographi
c entanglement entropy in more familiar settings.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Blaise Gouteraux (École Polytechnique)
DTSTART:20210108T110000Z
DTEND:20210108T120000Z
DTSTAMP:20260404T110915Z
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 Seminar
s\n\n\nAbstract\nHydrodynamics provides a universal description of interac
ting quantum field theories at sufficiently long times and wavelengths\, b
ut breaks down at scales dependent on microscopic details of the theory. W
e use gauge-gravity duality to investigate the breakdown of diffusive hydr
odynamics in two low temperature states dual to black holes with AdS2 hori
zons. We find that the breakdown is characterized by a collision between t
he diffusive pole of the retarded Green's function with a pole associated
to the AdS2 region of the geometry\, such that the local equilibration tim
e is set by infra-red properties of the theory. The absolute values of the
frequency and wavevector at the collision (ωeq and keq) provide a natura
l characterization of all the low temperature diffusivities D of the state
s via D=ωeq/keq^2 where ωeq=2πΔT is set by the temperature T and the s
caling dimension Δ of an infra-red operator. We confirm that these relati
ons are also satisfied in an SYK chain model in the limit of strong intera
ctions.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ben Craps (VUB)
DTSTART:20210112T110000Z
DTEND:20210112T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/31
DESCRIPTION:Title: Slow scrambling in extremal BTZ and microstate geometries\nby
Ben Craps (VUB) as part of CCTP HEP Seminars\n\n\nAbstract\nOut-of-time-o
rder correlators (OTOCs) that capture maximally chaotic properties of a bl
ack hole are determined by scattering processes near the horizon. This pro
mpts the question to what extent OTOCs display chaotic behaviour in horizo
nless microstate geometries. This question is complicated by the fact that
Lyapunov growth of OTOCs requires nonzero temperature\, whereas construct
ions of microstate geometries have been mostly restricted to extremal blac
k holes. We compute OTOCs for a class of extremal black holes\, namely max
imally rotating BTZ black holes\, and show that on average they display "s
low scrambling"\, characterized by cubic (rather than exponential) growth.
Superposed on this average power-law growth is a sawtooth pattern\, whose
steep parts correspond to brief periods of Lyapunov growth associated to
the nonzero temperature of the right-moving degrees of freedom in a dual c
onformal field theory. Next we study the extent to which these OTOCs are m
odified in certain "superstrata"\, horizonless microstate geometries corre
sponding 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 maxi
mally rotating BTZ black holes\, except that for large enough time interva
ls the growth of the OTOC is cut off by effects related to the cap region\
, some of which we evaluate explicitly.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Wilke van der Schee (CERN)
DTSTART:20210119T110000Z
DTEND:20210119T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/32
DESCRIPTION:Title: Entanglement entropy in expanding spacetimes\nby Wilke van de
r Schee (CERN) as part of CCTP HEP Seminars\n\n\nAbstract\nThis talk will
be about entanglement entropy in empty 4-dimensional de Sitter spacetime o
f 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 evolutio
ns of the event and apparent horizons\, showing in particular that the tem
perature of the event horizon approaches the de Sitter temperature. Intere
stingly\, in the empty setting we can show that extremal surfaces in the h
olographic dual of spherical entangling regions on the boundary QFT probe
beyond the dual event horizon if and only if the entangling region is larg
er than the cosmological horizon.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joao Penedones (EPFL)
DTSTART:20210126T110000Z
DTEND:20210126T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/33
DESCRIPTION:Title: Bootstrapping Quantum Field Theories\nby Joao Penedones (EPFL
) as part of CCTP HEP Seminars\n\n\nAbstract\nI will review the recent rev
ival of the S-matrix Bootstrap program. In particular\, I will discuss the
formulation that includes scattering amplitudes\, form factors and spectr
al densities.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dieter Lust (Max-Planck Institute)
DTSTART:20210202T110000Z
DTEND:20210202T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/34
DESCRIPTION:Title: The swampland at large number of space-time dimensions\nby Di
eter Lust (Max-Planck Institute) as part of CCTP HEP Seminars\n\n\nAbstrac
t\nWe discuss some aspects of swampland constraints - especially the swamp
land distance conjecture - in a large number of space-time dimensions D. W
e analyze Kaluza-Klein (KK) states at large D and find that some KK spectr
a possess an interesting dependence on D. On the basis of these observatio
ns we propose a new large dimension conjecture. We apply it to KK states o
f compactifications to anti-de Sitter backgrounds where it predicts an upp
er bound on the dimension of space-time as a function of its characteristi
c radius. We also apply our conjecture to black hole spacetimes\, whose en
tropies have a D-dependence very similar to that of the KK spectrum.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alessandro Georgoudis (IPhT Saclay)
DTSTART:20210330T100000Z
DTEND:20210330T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/35
DESCRIPTION:Title: Supergravity Amplitudes on AdS5×S5 and their flat-space limit\nby Alessandro Georgoudis (IPhT Saclay) as part of CCTP HEP Seminars\n\n
\nAbstract\nWe will study the four point function of the superconformal pr
imary of the stress-tensor multiplet in four dimensional N=4 Super Yang Mi
lls\, at large 't Hooft coupling and in a large N expansion. This observab
le is holographically dual to four graviton amplitudes in type IIB supergr
avity on AdS5×S5. We first will construct the most trascendental piece of
the correlator at any order in a large N expansion. They are determined o
nly by leading order CFT data. By focusing on a specific limit\, we make c
onnection with the dual supergravity amplitude in flat space\, where such
structures correspond to iterated s-cuts. We make several checks and we co
njecture that the same interpretation holds for supergravity amplitudes on
AdS5×S5.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgi Dvali (Max Planck Institute)
DTSTART:20210209T110000Z
DTEND:20210209T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/36
DESCRIPTION:Title: S-matrix constraints on de Sitter and on black holes\nby Geor
gi Dvali (Max Planck Institute) as part of CCTP HEP Seminars\n\n\nAbstract
\nWe discuss how the S-matrix formulation of quantum gravity/string theory
excludes any sort of stable or a metastable de Sitter. The constraint is
enforced by the phenomenon of quantum break-time. This has a number of obs
ervable consequences both for early and late cosmology. In particular\, it
excludes cosmological constant as part of the energy budget in the Univer
se. We confront the quantum portraits of de Sitter and black holes and poi
nt out similarities as well as fundamental differences.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bzowski (UOC)
DTSTART:20210216T110000Z
DTEND:20210216T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/37
DESCRIPTION:Title: Consistency of supersymmetric 't Hooft anomalies\nby Adam Bzo
wski (UOC) as part of CCTP HEP Seminars\n\n\nAbstract\nWe consider recent
claims that supersymmetry is anomalous in the presence of a R-symmetry ano
maly. We revisit arguments that such an anomaly in supersymmetry can be re
moved and write down an explicit counterterm that accomplishes it. Removal
of the supersymmetry anomaly requires enlarging the corresponding current
multiplet. As a consequence the Ward identities for other symmetries that
are already anomalous acquire extra terms. This procedure can only be imp
eded when the choice of current multiplet is forced. We show how Wess-Zumi
no consistency conditions are modified when the anomaly is removed. Finall
y we check that the modified Wess-Zumino consistency conditions are satisf
ied\, and supersymmetry unbroken\, in an explicit one loop computation usi
ng Pauli-Villars regulators. To this end we comment on how to use Pauli-Vi
llars to regulate correlators of components of (super)current multiplets i
n a manifestly supersymmetric way.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian Jepsen (Stony Brook)
DTSTART:20210309T150000Z
DTEND:20210309T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/38
DESCRIPTION:Title: Tensor Models and Limit Cycles\nby Christian Jepsen (Stony Br
ook) 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 existence of fixed points of the beta functions where the the couplin
g constants gi are real but the scaling dimensions\, as determined by the
eigenvalues of the Jacobian matrix ∂βi/∂gj\, are complex. When these
complex eigenvalues cross the imaginary axis\, a Hopf bifurcation takes pl
ace 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://stable.researchseminars.org/talk/CCTP_HEP/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikhail Shaposhnikov (EPFL Lausanne)
DTSTART:20210223T110000Z
DTEND:20210223T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/39
DESCRIPTION:Title: Einstein-Cartan gravity: Inflation\, Dark Matter and Electroweak
Symmetry Breaking\nby Mikhail Shaposhnikov (EPFL Lausanne) as part of
CCTP HEP Seminars\n\n\nAbstract\nIt is well-known since the works of Utiya
ma and Kibble that the gravitational force can be obtained by gauging the
Lorentz group\, which puts gravity on the same footing as the Standard Mod
el fields. The resulting theory - Einstein-Cartan gravity - happens to be
very interesting. First\, it incorporates Higgs inflation at energies belo
w the onset of the strong-coupling of the theory. Second\, it contains a f
our-fermion interaction that originates from torsion associated with spin
degrees of freedom. This interaction leads to a novel universal mechanism
for producing singlet fermions in the Early Universe. These fermions can p
lay the role of dark matter particles. Finally\, it may generate the elect
roweak symmetry breaking by a non-perturbative gravitational effect.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eric Perlmutter (Caltech)
DTSTART:20210316T110000Z
DTEND:20210316T120000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/40
DESCRIPTION:Title: A CFT Distance Conjecture\nby Eric Perlmutter (Caltech) as pa
rt of CCTP HEP Seminars\n\n\nAbstract\nWe formulate conjectures relating t
he geometry of conformal manifolds to the spectrum of local operators in c
onformal field theories in d>2 spacetime dimensions. We focus on conformal
manifolds with limiting points at infinite distance with respect to the Z
amolodchikov metric. Our central conjecture is that all theories at infini
te distance possess an emergent higher-spin symmetry\, generated by an inf
inite tower of currents whose anomalous dimensions vanish exponentially in
the distance. Our conjectures are related to the Distance Conjecture in t
he swampland program. We discuss the supporting evidence\, their holograph
ic interpretation\, and implications for superconformal field theories.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miguel Montero (Harvard)
DTSTART:20210323T150000Z
DTEND:20210323T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/41
DESCRIPTION:Title: Chern-Weil global symmetries and completeness of the spectrum
\nby Miguel Montero (Harvard) as part of CCTP HEP Seminars\n\n\nAbstract\n
Perhaps the oldest Swampland conjecture in the book is the absence of glob
al symmetries. I will describe the consequences of applying this conjectur
e to a particular class of symmetries\, Chern-Weil symmetries\, that are u
biquitous in string compactifications and which arise from powers of field
strenghts. I will explore the processes by which Chern-Weil symmetries may
be broken or gauged in effective field theory and string theory. This wil
l allow us to derive the existence of familiar features of string theory\,
such as worldvolume degrees of freedom in branes. Another lore holds that
absence global symmetries in a quantum field theory is equivalent to havi
ng a complete spectrum of charged states in the theory. I will discuss and
make precise this connection\, and explain and how a particular version o
f it can be proven in pure gauge theory with arbitrary (even disconnected)
gauge group.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Konstantinos Roumbedakis (Stony Brook)
DTSTART:20210406T150000Z
DTEND:20210406T160000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/42
DESCRIPTION:Title: Symmetries and Strings of adjoint QCD in two dimensions\nby K
onstantinos Roumbedakis (Stony Brook) as part of CCTP HEP Seminars\n\n\nAb
stract\nIn this talk\, we will review the notion of non-invertible symmetr
ies and we will study adjoint QCD in two dimensions. It turns out that thi
s theory has a plethora of such symmetries which require deconfinement in
the massless case. When a mass or certain quartic interactions are tunrned
on\, these symmetries are broken and the theory confines. In addition\, w
e will use these symmetries to calculate the string tension for small mass
and make some comments about naturalness along the RG flow.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Karananas (Munich)
DTSTART:20210413T100000Z
DTEND:20210413T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/43
DESCRIPTION:Title: Spontaneous Conformal Symmetry Breaking in the Fishnet CFT\nb
y Georgios Karananas (Munich) as part of CCTP HEP Seminars\n\n\nAbstract\n
Quantum field theories with exact but spontaneously broken conformal invar
iance have an intriguing feature: their vacuum energy is equal to zero. Up
to now\, the only known ultraviolet complete theories where conformal sym
metry can be spontaneously broken were associated with supersymmetry\, wit
h the most prominent example being the N =4 SYM. Interestingly\, its non-s
upersymmetric descendant\, the "Fishnet theory\," supports at the classica
l level a rich set of flat directions along which conformal symmetry is sp
ontaneously broken. At least perturbatively\, some of these vacua survive
in the full quantum theory - in the planar limit - without any finetuning.
As a result\, the vacuum energy vanishes along these flat directions\, pr
oviding the first non-supersymmetric example of a four-dimensional quantum
field theory with "natural" breaking of conformal symmetry.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/43/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Georgios Papathanasiou (DESY)
DTSTART:20210504T100000Z
DTEND:20210504T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/44
DESCRIPTION:Title: Cluster Algebras for Feynman Integrals\nby Georgios Papathana
siou (DESY) as part of CCTP HEP Seminars\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/44/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Riccardo Rattazzi (EPFL)
DTSTART:20210511T100000Z
DTEND:20210511T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/45
DESCRIPTION:Title: The quantum mechanics of a perfect fluid\nby Riccardo Rattazz
i (EPFL) as part of CCTP HEP Seminars\n\n\nAbstract\nFinite density system
s can be described by effective field\ntheories with non-linearly realized
space-time symmetries\,\nwhose construction resembles that of the QCD chi
ral lagrangian. Also\nbased on that similarity\, one would expect the\ncon
struction to work equally well classically and quantum mechanically.\nWhil
e that is true for superfluids and solids\,\none instead finds that for ge
nuine fluids things are made more\ncomplicated by the unusual dynamics of
their transverse\nmodes\, which are not described by a Fock space. Focuss
ing on the\nincompressible limit in 2+1 dimensions\, I illustrate how a co
nsistent\nquantum mechanical description of a perfect fluid can be obtaine
d by\nusing the known equivalence between the area preserving diffeomorfis
m \ngroup in 2D and $SU(N)$ with $N\\to \\infty$.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/45/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shiraz Minwalla (TIFR)
DTSTART:20210420T100000Z
DTEND:20210420T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/46
DESCRIPTION:by Shiraz Minwalla (TIFR) as part of CCTP HEP Seminars\n\nAbst
ract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/46/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gui Pimentel (Amsterdam)
DTSTART:20210427T130000Z
DTEND:20210427T140000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/47
DESCRIPTION:Title: Decoding and bootstrapping cosmological fluctuations\nby Gui
Pimentel (Amsterdam) as part of CCTP HEP Seminars\n\n\nAbstract\nI will re
view our current understanding of the initial conditions of the universe\,
and describe what information is available from current and future measur
ements of cosmological correlation functions. Then I will describe a new m
ethod to compute and constrain the possible shapes of those correlation fu
nctions\, assuming they were generated during inflation. This ``cosmologic
al bootstrap" draws inspiration from the modern scattering amplitudes prog
ram in flat space\, as well as the conformal bootstrap of phase transition
s. After discussing primordial scalar fluctuations\, I will also explain h
ow the consistent propagation of gravitational waves imposes further const
raints on the structure of spinning primordial correlators.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/47/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Zhiboedov (CERN)
DTSTART:20210518T100000Z
DTEND:20210518T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/49
DESCRIPTION:Title: Probing gravitational EFTs with the four-graviton amplitude\n
by Alexander Zhiboedov (CERN) as part of CCTP HEP Seminars\n\n\nAbstract\n
We discuss constraints from perturbative unitarity and\ncrossing on the le
ading contributions of the higher-dimension operators\nto the four-gravito
n amplitude in four spacetime dimensions. We focus on\nthe leading order e
ffect due to exchange by massive degrees of freedom\nwhich makes the ampli
tudes of interest IR finite. To test the\nconstraints we obtain nontrivial
effective field theory data by\ncomputing and taking the large mass expan
sion of the one-loop\nminimally-coupled four-graviton amplitude with massi
ve particles up to\nspin 2 circulating in the loop. Remarkably\, the leadi
ng EFT corrections\nto Einstein gravity of physical theories\, both string
theory and QFT\ncoupled to gravity\, end up in minuscule islands which ar
e much smaller\nthan what is suggested by the generic bounds obtained from
consistency\nof the 2-2 graviton scattering amplitude. We discuss the und
erlying\nmechanism for this phenomenon.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/49/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pawel Caputa (Warsaw)
DTSTART:20210525T100000Z
DTEND:20210525T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/50
DESCRIPTION:Title: Holographic Path Integral Optimization\nby Pawel Caputa (Wars
aw) as part of CCTP HEP Seminars\n\n\nAbstract\nI will talk about recent w
ork on understanding path integral optimization in CFTs holographically us
ing Hartle-Hawking wave functions in AdS. The talk will be based on arXiv:
2011.08188 [hep-th] and 2104.00010 [hep-th].\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/50/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Victor Gorbenko (Stanford)
DTSTART:20210601T100000Z
DTEND:20210601T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/51
DESCRIPTION:Title: Bra-ket wormholes in gravitationally prepared states\nby Vict
or Gorbenko (Stanford) as part of CCTP HEP Seminars\n\n\nAbstract\nWe will
discuss two-dimensional toy-models of inflation in which the state of the
universe is prepared by a gravitational path integral. As a first model\,
we consider a state produced by Euclidean AdS_2 evolution followed by fla
t space evolution. We use the fine grained entropy formula to explore the
nature of the state. We find that the naive hyperbolic space geometry (ana
log 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 semiclassical Lorentzian interpretation leads to CFT state entangled
with an expanding and collapsing Friedmann cosmology. I will then describ
e a similar model where the state is prepared by the dS_2 evolution and hi
ghlight related puzzles.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/51/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Enrico Pajer (Cambridge)
DTSTART:20210608T100000Z
DTEND:20210608T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/52
DESCRIPTION:Title: A Timeless History of Time\nby Enrico Pajer (Cambridge) as pa
rt of CCTP HEP Seminars\n\n\nAbstract\nCosmological observations give us t
he unique opportunity to\nprobe the fundamental laws of physics at very hi
gh energies as well as\nthe perturbative regime of quantum gravity. Unfort
unately\, due to the\ncreativity of theorists and the paucity of data abou
t the primordial\nuniverse\, there is a huge number of models compatible w
ith all\nmeasurements\, featuring a wide variety of mechanisms\, symmetrie
s\, and\nspectra of particles.The reason can be traced back to the fact th
at we\ndon't observe the time evolution during inflation\, but only its fi
nal\noutcome.\n\nIn this talk I will report on the recent progress in deve
loping a\ncompletely new "bootstrap" approach to derive predictions from t
he very\nearly universe that make no reference to time and the un-observab
le time\nevolution. The bootstrap approach builds directly upon the fundam
ental\npillars of physics. In particular\, I will present the recent\nbrea
kthroughs in understanding the consequence of unitarity for\ncosmological
correlators to all orders in perturbation theory\, as well\nas the footpri
nt of (bulk) locality. I will show how these principles\ncan be used to de
rive many classical and new inflationary predictions\nassociated with prim
ordial non-Gaussianity in a way that is both\ncomputationally simpler and
conceptually more transparent. This includes\na reconstruction formula tha
t relates de Sitter correlators to\namplitudes for massless particles\, co
smological partial-energy recursion\nrelations and a "timeless" differenti
al representation of the\nperturbative wavefunction. This approach makes n
o reference to de Sitter\nboosts\, which are broken by a large amount in m
odels that predict large\nnon-Gaussianity.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/52/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kostas Skenderis (Southampton)
DTSTART:20210615T100000Z
DTEND:20210615T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/53
DESCRIPTION:Title: Holographic cosmology and the origin of time\nby Kostas Skend
eris (Southampton) as part of CCTP HEP Seminars\n\n\nAbstract\nHolographic
cosmology is a new framework for the very early universe\, the period usu
ally associated with inflation. In holographic cosmology the early Univers
e is described by a three dimensional QFT\, and cosmological evolution is
mapped to inverse RG flow. In this talk\, I will provide an overview of ho
lographic cosmology and then discuss recent work where lattice QFT methods
are used to compute the relevant QFT observables. In particular\, I will
discuss the IR structure of the dual QFT\, which is linked to the initial
singularity in cosmology\, and show how non-perturbative dynamics resolve
the IR singularities present in perturbation theory\, thus providing a hol
ographic resolution of the Big Bang singularity.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/53/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dam Son (Chicago)
DTSTART:20210622T140000Z
DTEND:20210622T150000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/54
DESCRIPTION:Title: Volume preserving diffeomorphism as a higher-rank gauge symmetry<
/a>\nby Dam Son (Chicago) as part of CCTP HEP Seminars\n\n\nAbstract\nRece
ntly\, theories with higher rank gauge symmetries are drawing attention in
condensed matter physics. Such theories are thought to be related to the
so-called "fractons\," quasiparticles with limited mobility that appear in
some lattice models. We show that one version of such higher ranked symme
try can be "nonlinearlized" into volume-preserving diffeomorphism. We demo
nstrate that several condensed matter systems\, including the fractional q
uantum Hall effect and ferromagnetism\, secretly possess this symmetry\, w
hich sheds another light to some peculiar features of the quasiparticles i
n these systems.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/54/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioanna Kourkoulou (Columbia)
DTSTART:20210629T140000Z
DTEND:20210629T150000Z
DTSTAMP:20260404T110915Z
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\nAbstract\nThe Framid is a hypothetical system whose ground state\nspo
ntaneously breaks boost symmetry\, however its stress-energy tensor\nretai
ns a Lorentz-invariant expectation value on the ground state\, as we\nveri
fy explicitly to one-loop order. The mechanism enforcing this result\nis r
ather obscure\; in fact\, we think this puzzle is an interesting\ntechnica
l analog of the cosmological constant problem. I will describe\nour comput
ations that verify the Lorentz invariance of the expectation\nvalue in que
stion\, and how these yield the expected result only thanks\nto highly non
trivial cancellations\, which are quite mysterious from the\nlow-energy ef
fective theory viewpoint.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/55/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Rizos (Ioannina U.)
DTSTART:20210706T100000Z
DTEND:20210706T110000Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/56
DESCRIPTION:Title: On nonsupersymmetric string models and the decompactification pro
blem\nby John Rizos (Ioannina U.) as part of CCTP HEP Seminars\n\n\nAb
stract\nWe study 4d heterotic string compactifications exhibiting\nspontan
eous supersymmetry breaking via the Scherk–Schwarz mechanism\nassociated
with two large internal dimensions. We identify a class of\nmodels with f
ermion–boson degeneracy that address some central issues in\nnonsupersym
metric string phenomenology including the elimination of\ntachyons and dil
aton tadpoles and the suppression of the cosmological\nconstant. In additi
on\, we propose a novel solution to the\ndecompactification problem relate
d to the cancellation of the linear\ngrowth of the gauge part of the thres
holds with a similar growth of the\nuniversal part.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/56/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dimitrios Patramanis (Warsaw)
DTSTART:20210727T101500Z
DTEND:20210727T111500Z
DTSTAMP:20260404T110915Z
UID:CCTP_HEP/57
DESCRIPTION:Title: A geometric perspective on the holographic Berry phase\nby Di
mitrios Patramanis (Warsaw) as part of CCTP HEP Seminars\n\n\nAbstract\nAf
ter briefly reviewing the notions of Berry's phase and\ncoadjoint orbits I
will be explaining how these arise in a holographic\nsetup. Namely\, I wi
ll be talking about the modular Berry phase arising\nin AdS3/CFT2 and the
prospects of its generalization in the broader\ncontext of the Banados geo
metries. To this end I will be discussing the\ndifferent tools and methods
required to do so and attempt to highlight\ntheir utility in addressing b
oth questions in holography and problems of\na more general nature.\n
LOCATION:https://stable.researchseminars.org/talk/CCTP_HEP/57/
END:VEVENT
END:VCALENDAR