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BEGIN:VEVENT
SUMMARY:Netta Engelhardt (Massachusetts Institute of Technology)
DTSTART:20201207T150000Z
DTEND:20201207T160000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/1
DESCRIPTION:Title: Free Energy from Replica Wormholes\nby Netta Engelhardt
(Massachusetts Institute of Technology) as part of Online Workshop on Qubi
ts and Black Holes\n\n\nAbstract\nI will discuss progress towards understa
nding the relationship between the gravitational path integral and the par
tition function via the gravitational free energy (more generally the gene
rating functional). A proper computation of the free energy requires a rep
lica trick distinct from the usual one used to compute the entropy. I will
show that in JT gravity there is a regime where the free energy computed
without replica wormholes is pathological. Interestingly\, the naive inclu
sion of replica wormholes is not quite sufficient to resolve the pathology
: an alternative analytic continuation is required. I will discuss the imp
lications of this for various interpretations of the gravitational path in
tegral (e.g. as computing an ensemble average) and also mention some paral
lels with spin glasses.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex May (University of British Columbia)
DTSTART:20201207T160000Z
DTEND:20201207T170000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/2
DESCRIPTION:Title: Quantum Tasks in Holography\nby Alex May (University of
British Columbia) as part of Online Workshop on Qubits and Black Holes\n\n
\nAbstract\nQuantum tasks are quantum computations which have inputs and o
utputs that occur at designated spacetime locations. Understanding which t
asks are possible to complete\, and what resources are required to complet
e them\, captures spacetime-specific aspects of quantum information. In th
is talk we explore how an understanding of quantum tasks can be applied to
AdS/CFT. We find that tasks reveal a connection between causal features o
f bulk geometry and boundary entanglement. We discuss the connected wedge
theorem\, which makes this connection precise. In the context of AdS space
times with end-of-the-world branes\, the connected wedge theorem suggests
a causal relationship between islands and their corresponding radiation sy
stems.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mukund Rangamani (University of California\, Davis)
DTSTART:20201207T180000Z
DTEND:20201207T190000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/3
DESCRIPTION:Title: Real-Time Gravitational Replicas\nby Mukund Rangamani (U
niversity of California\, Davis) as part of Online Workshop on Qubits and
Black Holes\n\n\nAbstract\nI will discuss real-time path integrals in grav
itational theories. As applications we will describe the general structure
of replica wormhole saddles and the effective dynamics of open quantum sy
stems with long-term memory.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Adam Bouland (University of California\, Berkeley)
DTSTART:20201207T190000Z
DTEND:20201207T200000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/4
DESCRIPTION:Title: Pseudorandomness and the AdS/CFT Correspondence\nby Adam
Bouland (University of California\, Berkeley) as part of Online Workshop
on Qubits and Black Holes\n\n\nAbstract\nCould quantum circuit complexity
have physical ramifications? In the context of AdS/CFT\, Susskind has sugg
ested that it might\, as circuit complexity could be the CFT dual to AdS w
ormhole volume. Here we explore this proposal using cryptographic techniqu
es. We first show how to create pseudorandom quantum states in the CFT\, t
hereby arguing that their quantum circuit complexity is not "feelable"\, i
n the sense that it cannot be approximated by any efficient experiment. By
contrast we argue that the wormhole volume is "feelable" in some general
but non-physical sense. The duality between a "feelable" quantity and an "
unfeelable" quantity implies that some aspect of this duality -- either th
e AdS/CFT dictionary\, or else the dynamics of quantum gravity -- must hav
e exponential complexity. While at first sight this might seem to justify
the discomfort of complexity theorists with equating complexity with a phy
sical quantity\, a further examination of our arguments shows that these c
onclusions are an inevitable consequence of the "wormhole growth paradox"
which inspired this proposal in the first place. Based largely on https://
arxiv.org/abs/1910.14646\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Mertens (Ghent University)
DTSTART:20201208T150000Z
DTEND:20201208T160000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/5
DESCRIPTION:Title: Liouville and JT Quantum Gravity - Holography and Matrix Mod
els\nby Thomas Mertens (Ghent University) as part of Online Workshop o
n Qubits and Black Holes\n\n\nAbstract\nI will discuss recent progress in
understanding quantum gravity amplitudes (partition function\, boundary co
rrelation functions and multiboundary amplitudes) in Liouville gravity\, a
nd how they limit to Jackiw-Teitelboim (JT) amplitudes. I will provide two
perspectives on the results: the Liouville gravity answers look like q-de
formations of the JT answers\, and Liouville gravity can be related to a 2
d dilaton gravity with a sinh dilaton potential. Based largely on arXiv:20
06.07072 and 2007.00998.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Javier Magan (Instituto Balseiro\, Centro Atómico de Bariloche)
DTSTART:20201208T160000Z
DTEND:20201208T170000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/6
DESCRIPTION:Title: Entropic Order Parameters for the Phases of QFT\nby Javi
er Magan (Instituto Balseiro\, Centro Atómico de Bariloche) as part of On
line Workshop on Qubits and Black Holes\n\n\nAbstract\nWe start by describ
ing how generalized symmetries in QFT arise in the violation of elementary
properties that appear when we associate algebras to regions in QFT. This
observation provides a new perspective/proof of the abelian nature of gen
eralized symmetries. Further\, the algebra of order/disorder parameters is
fixed and can be deduced without the explicit construction of the non-loc
al operators. In these scenarios\, there are two natural algebras associat
ed with regions of specific topologies\, suggesting a simple geometrical o
rder parameter defined as a relative entropy. These relative entropies sat
isfy a “certainty relation” connecting the statistics of the order and
disorder 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/IAS_Qubit_2020/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monika Schleier-Smith (Stanford University)
DTSTART:20201208T180000Z
DTEND:20201208T190000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/7
DESCRIPTION:Title: Programmable Non-Local Interactions: Towards Fast Scrambling
with Cold Atoms\nby Monika Schleier-Smith (Stanford University) as pa
rt of Online Workshop on Qubits and Black Holes\n\n\nAbstract\nThe quest t
o build and probe toy models of quantum gravity in table-top experiments p
resents a new frontier for the field of quantum simulation. One challenge
is to simulate fast scrambling of quantum information in black holes\, for
which a key requirement is to engineer a quantum system with a non-local
graph of interactions. I will report on advances in control of non-local i
nteractions in experiments with cold atoms. By coupling the atoms to light
in an optical resonator\, we generate tunable non-local Heisenberg intera
ctions\, which we characterize by imaging the resulting phases and dynamic
s. Notable observations include interaction-based protection of spin coher
ence and photon-mediated spin-mixing\, a mechanism for generating correlat
ed atom pairs. I will present recent results on optically programming the
distance-dependence of the spin-spin couplings\, with prospects for studyi
ng fast scrambling and for accessing treelike (p-adic) geometries akin to
hyperbolic space.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Douglas Stanford (Stanford University)
DTSTART:20201208T190000Z
DTEND:20201208T200000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/8
DESCRIPTION:Title: Comments about Wormholes and Quantum Noise\nby Douglas S
tanford (Stanford University) as part of Online Workshop on Qubits and Bla
ck Holes\n\n\nAbstract\nWe will comment on wormholes for the off-diagonal
components of the density matrix of Hawking radiation. Then we will discus
s work in progress on a simple model in which small effects associated wit
h unitarity of time evolution may be related to further topologies.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Edward Witten (Institute for Advanced Study)
DTSTART:20201209T150000Z
DTEND:20201209T160000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/9
DESCRIPTION:Title: Some Comments on Energy Inequalities\nby Edward Witten (
Institute for Advanced Study) as part of Online Workshop on Qubits and Bla
ck Holes\n\n\nAbstract\nThe talk will consist of some general observations
about energy inequalities\, such as the statement that the energy density
averaged over a time-like curve is bounded below and the statement that t
he averaged null energy on a null geodesic in Minkowski space is nonnegati
ve.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lampros Lamprou (Massachusetts Institute of Technology)
DTSTART:20201209T160000Z
DTEND:20201209T170000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/10
DESCRIPTION:Title: Inside the Hologram: The Bulk Observer's Experience\nby
Lampros Lamprou (Massachusetts Institute of Technology) as part of Online
Workshop on Qubits and Black Holes\n\n\nAbstract\nI will present a hologr
aphic framework for reconstructing the experience of bulk observers in AdS
/CFT. In particular\, I will show how to recover the proper time and energ
y distribution measured along bulk worldlines\, directly in the CFT via a
universal\, background-independent prescription. For an observer falling i
nto an eternal AdS black hole\, the proposal resolves a conceptual puzzle
raised by Marolf and Wall. It suffers\, however\, from the "frozen vacuum"
problem for which I will offer some preliminary comments. Notably\, the a
pproach does not depend crucially on the asymptotic Hamiltonian and it out
lines a general framework for the emergence of time.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Akers (Massachusetts Institute of Technology)
DTSTART:20201209T180000Z
DTEND:20201209T190000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/11
DESCRIPTION:Title: Quantum Minimal Surfaces in Quantum Error-Correction\nb
y Chris Akers (Massachusetts Institute of Technology) as part of Online Wo
rkshop on Qubits and Black Holes\n\n\nAbstract\nWhat is the role of quantu
m extremal surfaces (QES) in general quantum error-correcting codes? I wil
l present preliminary results starting to answer this question\, expanding
on the previous work of Harlow\, providing necessary and sufficient condi
tions for a general code to satisfy a quantum minimal surface prescription
.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Geoffrey Penington (University of California\, Berkeley)
DTSTART:20201209T190000Z
DTEND:20201209T200000Z
DTSTAMP:20260404T094834Z
UID:IAS_Qubit_2020/12
DESCRIPTION:Title: Life without Pythons would be so Simple\nby Geoffrey Pe
nington (University of California\, Berkeley) as part of Online Workshop o
n Qubits and Black Holes\n\n\nAbstract\nReconstruction of bulk operators w
ithin the causal wedge is simple to achieve using Lorentzian causal bulk d
ynamics. In contrast\, the only known methods for reconstructing arbitrary
operators in the full entanglement wedge (the Petz map\, modular flow etc
.) are highly complex from a boundary perspective. It was previously argue
d based on intuition from tensor networks that this complexity is necessar
y 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 lunch\, but are also not in the causal wedge. I will argue that such op
erators can also be simply\, and causally\, reconstructed by gradually exp
anding the causal wedge using time folds with different boundary condition
s.\n
LOCATION:https://stable.researchseminars.org/talk/IAS_Qubit_2020/12/
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