BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Netta Engelhardt (Massachusetts Institute of Technology)
DTSTART:20201207T150000Z
DTEND:20201207T160000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/1
DESCRIPTION:Title: Free Energy from Replica Wormholes\nby Netta Engelhardt (M
assachusetts Institute of Technology) as part of Online Workshop on Qubits
and Black Holes\n\n\nAbstract\nI will discuss progress towards understand
ing the relationship between the gravitational path integral and the parti
tion function via the gravitational free energy (more generally the genera
ting functional). A proper computation of the free energy requires a repli
ca trick distinct from the usual one used to compute the entropy. I will s
how that in JT gravity there is a regime where the free energy computed wi
thout replica wormholes is pathological. Interestingly\, the naive inclusi
on of replica wormholes is not quite sufficient to resolve the pathology:
an alternative analytic continuation is required. I will discuss the impli
cations of this for various interpretations of the gravitational path inte
gral (e.g. as computing an ensemble average) and also mention some paralle
ls with spin glasses.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex May (University of British Columbia)
DTSTART:20201207T160000Z
DTEND:20201207T170000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/2
DESCRIPTION:Title: Quantum Tasks Require Islands on the Brane\nby Alex May (U
niversity of British Columbia) as part of Online Workshop on Qubits and Bl
ack Holes\n\n\nAbstract\nIn recent work\, it was argued that quantum compu
tations with inputs and outputs distributed in spacetime\, or quantum task
s\, impose constraints on entanglement in holographic theories. The result
ing constraint was named the connected wedge theorem and can verified by a
direct bulk proof using focusing arguments in general relativity. In this
talk we extend this work to the context of AdS/BCFT\, where an end-of-the
-world brane is present in the bulk. By considering quantum tasks which ex
ploit information localized to the brane\, we find a new connected wedge t
heorem. We apply this theorem to brane models of black holes\, where it re
lates the formation of Islands in the Ryu-Takayanagi formula to causal fea
tures of the ambient spacetime. In particular we find that in simple model
s Islands on the brane are causally connected to their corresponding radia
tion systems.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mukund Rangamani (University of California\, Davis)
DTSTART:20201207T180000Z
DTEND:20201207T190000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/3
DESCRIPTION:Title: Real-Time Gravitational Replicas\nby Mukund Rangamani (Uni
versity of California\, Davis) as part of Online Workshop on Qubits and Bl
ack Holes\n\n\nAbstract\nI will discuss real-time path integrals in gravit
ational theories. As applications we will describe the general structure o
f replica wormhole saddles and the effective dynamics of open quantum syst
ems with long-term memory.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bouland (University of California\, Berkeley)
DTSTART:20201207T190000Z
DTEND:20201207T200000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/4
DESCRIPTION:Title: Pseudorandomness and the AdS/CFT Correspondence\nby Adam B
ouland (University of California\, Berkeley) as part of Online Workshop on
Qubits and Black Holes\n\n\nAbstract\nCould quantum circuit complexity ha
ve physical ramifications? In the context of AdS/CFT\, Susskind has sugges
ted that it might\, as circuit complexity could be the CFT dual to AdS wor
mhole volume. Here we explore this proposal using cryptographic techniques
. We first show how to create pseudorandom quantum states in the CFT\, the
reby arguing that their quantum circuit complexity is not "feelable"\, in
the sense that it cannot be approximated by any efficient experiment. By c
ontrast we argue that the wormhole volume is "feelable" in some general bu
t non-physical sense. The duality between a "feelable" quantity and an "un
feelable" quantity implies that some aspect of this duality -- either the
AdS/CFT dictionary\, or else the dynamics of quantum gravity -- must have
exponential complexity. While at first sight this might seem to justify th
e discomfort of complexity theorists with equating complexity with a physi
cal quantity\, a further examination of our arguments shows that these con
clusions are an inevitable consequence of the "wormhole growth paradox" wh
ich inspired this proposal in the first place. Based largely on https://ar
xiv.org/abs/1910.14646\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Mertens (Ghent University)
DTSTART:20201208T150000Z
DTEND:20201208T160000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/5
DESCRIPTION:Title: Liouville and JT Quantum Gravity - Holography and Matrix Model
s\nby Thomas Mertens (Ghent University) as part of Online Workshop on
Qubits and Black Holes\n\n\nAbstract\nI will discuss recent progress in un
derstanding quantum gravity amplitudes (partition function\, boundary corr
elation functions and multiboundary amplitudes) in Liouville gravity\, and
how they limit to Jackiw-Teitelboim (JT) amplitudes. I will provide two p
erspectives on the results: the Liouville gravity answers look like q-defo
rmations of the JT answers\, and Liouville gravity can be related to a 2d
dilaton gravity with a sinh dilaton potential. Based largely on arXiv:2006
.07072 and 2007.00998.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Javier Magan (Instituto Balseiro\, Centro Atómico de Bariloche)
DTSTART:20201208T160000Z
DTEND:20201208T170000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/6
DESCRIPTION:Title: Entropic Order Parameters for the Phases of QFT\nby Javier
Magan (Instituto Balseiro\, Centro Atómico de Bariloche) as part of Onli
ne Workshop on Qubits and Black Holes\n\n\nAbstract\nWe start by describin
g how generalized symmetries in QFT arise in the violation of elementary p
roperties that appear when we associate algebras to regions in QFT. This o
bservation provides a new perspective/proof of the abelian nature of gener
alized symmetries. Further\, the algebra of order/disorder parameters is f
ixed and can be deduced without the explicit construction of the non-local
operators. In these scenarios\, there are two natural algebras associated
with regions of specific topologies\, suggesting a simple geometrical ord
er parameter defined as a relative entropy. These relative entropies satis
fy a “certainty relation” connecting the statistics of the order and d
isorder parameters. We describe old and new aspects of the phases of QFT
’s with generalized symmetries from this perspective. In particular\, th
e certainty relation makes transparent the duality between constant and ar
ea law behaviors in symmetry-breaking scenarios\, and in CFT’s there are
relative entropies exactly computable.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monika Schleier-Smith (Stanford University)
DTSTART:20201208T180000Z
DTEND:20201208T190000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/7
DESCRIPTION:Title: Programmable Non-Local Interactions: Towards Fast Scrambling w
ith Cold Atoms\nby Monika Schleier-Smith (Stanford University) as part
of Online Workshop on Qubits and Black Holes\n\n\nAbstract\nThe quest to
build and probe toy models of quantum gravity in table-top experiments pre
sents a new frontier for the field of quantum simulation. One challenge is
to simulate fast scrambling of quantum information in black holes\, for w
hich a key requirement is to engineer a quantum system with a non-local gr
aph of interactions. I will report on advances in control of non-local int
eractions in experiments with cold atoms. By coupling the atoms to light i
n an optical resonator\, we generate tunable non-local Heisenberg interact
ions\, which we characterize by imaging the resulting phases and dynamics.
Notable observations include interaction-based protection of spin coheren
ce and photon-mediated spin-mixing\, a mechanism for generating correlated
atom pairs. I will present recent results on optically programming the di
stance-dependence of the spin-spin couplings\, with prospects for studying
fast scrambling and for accessing treelike (p-adic) geometries akin to hy
perbolic space.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Douglas Stanford (Stanford University)
DTSTART:20201208T190000Z
DTEND:20201208T200000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/8
DESCRIPTION:Title: Comments about Wormholes and Quantum Noise\nby Douglas Sta
nford (Stanford University) as part of Online Workshop on Qubits and Black
Holes\n\n\nAbstract\nWe will comment on wormholes for the off-diagonal co
mponents of the density matrix of Hawking radiation. Then we will discuss
work in progress on a simple model in which small effects associated with
unitarity of time evolution may be related to further topologies.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edward Witten (Institute for Advanced Study)
DTSTART:20201209T150000Z
DTEND:20201209T160000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/9
DESCRIPTION:Title: Some Comments on Energy Inequalities\nby Edward Witten (In
stitute for Advanced Study) as part of Online Workshop on Qubits and Black
Holes\n\n\nAbstract\nThe talk will consist of some general observations a
bout energy inequalities\, such as the statement that the energy density a
veraged over a time-like curve is bounded below and the statement that the
averaged null energy on a null geodesic in Minkowski space is nonnegative
.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou (Massachusetts Institute of Technology)
DTSTART:20201209T160000Z
DTEND:20201209T170000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/10
DESCRIPTION:Title: Inside the Hologram: The Bulk Observer's Experience\nby L
ampros Lamprou (Massachusetts Institute of Technology) as part of Online W
orkshop on Qubits and Black Holes\n\n\nAbstract\nI will present a holograp
hic framework for reconstructing the experience of bulk observers in AdS/C
FT. In particular\, I will show how to recover the proper time and energy
distribution measured along bulk worldlines\, directly in the CFT via a un
iversal\, background-independent prescription. For an observer falling int
o an eternal AdS black hole\, the proposal resolves a conceptual puzzle ra
ised by Marolf and Wall. It suffers\, however\, from the "frozen vacuum" p
roblem for which I will offer some preliminary comments. Notably\, the app
roach does not depend crucially on the asymptotic Hamiltonian and it outli
nes a general framework for the emergence of time.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Akers (Massachusetts Institute of Technology)
DTSTART:20201209T180000Z
DTEND:20201209T190000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/11
DESCRIPTION:Title: Quantum Minimal Surfaces in Quantum Error-Correction\nby
Chris Akers (Massachusetts Institute of Technology) as part of Online Work
shop on Qubits and Black Holes\n\n\nAbstract\nWhat is the role of quantum
extremal surfaces (QES) in general quantum error-correcting codes? I will
present preliminary results starting to answer this question\, expanding o
n the previous work of Harlow\, providing necessary and sufficient conditi
ons for a general code to satisfy a quantum minimal surface prescription.\
n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Geoffrey Penington (University of California\, Berkeley)
DTSTART:20201209T190000Z
DTEND:20201209T200000Z
DTSTAMP:20260404T094750Z
UID:IASQubit2020/12
DESCRIPTION:Title: Life without Pythons would be so Simple\nby Geoffrey Peni
ngton (University of California\, Berkeley) as part of Online Workshop on
Qubits and Black Holes\n\n\nAbstract\nReconstruction of bulk operators wit
hin the causal wedge is simple to achieve using Lorentzian causal bulk dyn
amics. In contrast\, the only known methods for reconstructing arbitrary o
perators in the full entanglement wedge (the Petz map\, modular flow etc.)
are highly complex from a boundary perspective. It was previously argued
based on intuition from tensor networks that this complexity is necessary
if the bulk operator hidden behind an extremal surface (in a ‘python’s
lunch’). However in general there may be operators which are not in a l
unch\, but are also not in the causal wedge. I will argue that such operat
ors can also be simply\, and causally\, reconstructed by gradually expandi
ng the causal wedge using time folds with different boundary conditions.\n
LOCATION:https://stable.researchseminars.org/talk/IASQubit2020/12/
END:VEVENT
END:VCALENDAR