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:20260422T212934Z UID:IAS_Qubit_2020/1 DESCRIPTION:Title: Free Energy from Replica Wormholes\nby Netta Engelhardt (Massac husetts Institute of Technology) as part of Online Workshop on Qubits and Black Holes\n\n\nAbstract\nI will discuss progress towards understanding t he relationship between the gravitational path integral and the partition function via the gravitational free energy (more generally the generating functional). A proper computation of the free energy requires a replica tr ick distinct from the usual one used to compute the entropy. I will show t hat in JT gravity there is a regime where the free energy computed without replica wormholes is pathological. Interestingly\, the naive inclusion of replica wormholes is not quite sufficient to resolve the pathology: an al ternative analytic continuation is required. I will discuss the implicatio ns of this for various interpretations of the gravitational path integral (e.g. as computing an ensemble average) and also mention some parallels wi th spin glasses.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Alex May (University of British Columbia) DTSTART:20201207T160000Z DTEND:20201207T170000Z DTSTAMP:20260422T212934Z 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\nAbstr act\nQuantum tasks are quantum computations which have inputs and outputs that occur at designated spacetime locations. Understanding which tasks ar e possible to complete\, and what resources are required to complete them\ , captures spacetime-specific aspects of quantum information. In this talk we explore how an understanding of quantum tasks can be applied to AdS/CF T. We find that tasks reveal a connection between causal features of bulk geometry and boundary entanglement. We discuss the connected wedge theorem \, which makes this connection precise. In the context of AdS spacetimes w ith end-of-the-world branes\, the connected wedge theorem suggests a causa l relationship between islands and their corresponding radiation systems.\ n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Mukund Rangamani (University of California\, Davis) DTSTART:20201207T180000Z DTEND:20201207T190000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/3 DESCRIPTION:Title: Real-Time Gravitational Replicas\nby Mukund Rangamani (Universi ty of California\, Davis) as part of Online Workshop on Qubits and Black H oles\n\n\nAbstract\nI will discuss real-time path integrals in gravitation al theories. As applications we will describe the general structure of rep lica wormhole saddles and the effective dynamics of open quantum systems w ith long-term memory.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Adam Bouland (University of California\, Berkeley) DTSTART:20201207T190000Z DTEND:20201207T200000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/4 DESCRIPTION:Title: Pseudorandomness and the AdS/CFT Correspondence\nby Adam Boulan d (University of California\, Berkeley) as part of Online Workshop on Qubi ts and Black Holes\n\n\nAbstract\nCould quantum circuit complexity have ph ysical ramifications? In the context of AdS/CFT\, Susskind has suggested t hat it might\, as circuit complexity could be the CFT dual to AdS wormhole volume. Here we explore this proposal using cryptographic techniques. We first show how to create pseudorandom quantum states in the CFT\, thereby arguing that their quantum circuit complexity is not "feelable"\, in the s ense that it cannot be approximated by any efficient experiment. By contra st we argue that the wormhole volume is "feelable" in some general but non -physical sense. The duality between a "feelable" quantity and an "unfeela ble" quantity implies that some aspect of this duality -- either the AdS/C FT dictionary\, or else the dynamics of quantum gravity -- must have expon ential complexity. While at first sight this might seem to justify the dis comfort of complexity theorists with equating complexity with a physical q uantity\, a further examination of our arguments shows that these conclusi ons are an inevitable consequence of the "wormhole growth paradox" which i nspired this proposal in the first place. Based largely on https://arxiv.o rg/abs/1910.14646\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Mertens (Ghent University) DTSTART:20201208T150000Z DTEND:20201208T160000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/5 DESCRIPTION:Title: Liouville and JT Quantum Gravity - Holography and Matrix Models \nby Thomas Mertens (Ghent University) as part of Online Workshop on Qubit s and Black Holes\n\n\nAbstract\nI will discuss recent progress in underst anding quantum gravity amplitudes (partition function\, boundary correlati on functions and multiboundary amplitudes) in Liouville gravity\, and how they limit to Jackiw-Teitelboim (JT) amplitudes. I will provide two perspe ctives on the results: the Liouville gravity answers look like q-deformati ons of the JT answers\, and Liouville gravity can be related to a 2d dilat on gravity with a sinh dilaton potential. Based largely on arXiv:2006.0707 2 and 2007.00998.\n LOCATION:https://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:20260422T212934Z UID:IAS_Qubit_2020/6 DESCRIPTION:Title: Entropic Order Parameters for the Phases of QFT\nby Javier Maga n (Instituto Balseiro\, Centro Atómico de Bariloche) as part of Online Wo rkshop on Qubits and Black Holes\n\n\nAbstract\nWe start by describing how generalized symmetries in QFT arise in the violation of elementary proper ties that appear when we associate algebras to regions in QFT. This observ ation provides a new perspective/proof of the abelian nature of generalize d symmetries. Further\, the algebra of order/disorder parameters is fixed and can be deduced without the explicit construction of the non-local oper ators. In these scenarios\, there are two natural algebras associated with regions of specific topologies\, suggesting a simple geometrical order pa rameter defined as a relative entropy. These relative entropies satisfy a “certainty relation” connecting the statistics of the order and disord er parameters. We describe old and new aspects of the phases of QFT’s wi th generalized symmetries from this perspective. In particular\, the certa inty relation makes transparent the duality between constant and area law behaviors in symmetry-breaking scenarios\, and in CFT’s there are relati ve entropies exactly computable.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Monika Schleier-Smith (Stanford University) DTSTART:20201208T180000Z DTEND:20201208T190000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/7 DESCRIPTION:Title: Programmable Non-Local Interactions: Towards Fast Scrambling with C old Atoms\nby Monika Schleier-Smith (Stanford University) as part of O nline Workshop on Qubits and Black Holes\n\n\nAbstract\nThe quest to build and probe toy models of quantum gravity in table-top experiments presents a new frontier for the field of quantum simulation. One challenge is to s imulate fast scrambling of quantum information in black holes\, for which a key requirement is to engineer a quantum system with a non-local graph o f interactions. I will report on advances in control of non-local interact ions in experiments with cold atoms. By coupling the atoms to light in an optical resonator\, we generate tunable non-local Heisenberg interactions\ , which we characterize by imaging the resulting phases and dynamics. Nota ble observations include interaction-based protection of spin coherence an d photon-mediated spin-mixing\, a mechanism for generating correlated atom pairs. I will present recent results on optically programming the distanc e-dependence of the spin-spin couplings\, with prospects for studying fast scrambling and for accessing treelike (p-adic) geometries akin to hyperbo lic space.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Douglas Stanford (Stanford University) DTSTART:20201208T190000Z DTEND:20201208T200000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/8 DESCRIPTION:Title: Comments about Wormholes and Quantum Noise\nby Douglas Stanford (Stanford University) as part of Online Workshop on Qubits and Black Hole s\n\n\nAbstract\nWe will comment on wormholes for the off-diagonal compone nts of the density matrix of Hawking radiation. Then we will discuss work in progress on a simple model in which small effects associated with unita rity of time evolution may be related to further topologies.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Edward Witten (Institute for Advanced Study) DTSTART:20201209T150000Z DTEND:20201209T160000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/9 DESCRIPTION:Title: Some Comments on Energy Inequalities\nby Edward Witten (Institu te for Advanced Study) as part of Online Workshop on Qubits and Black Hole s\n\n\nAbstract\nThe talk will consist of some general observations about energy inequalities\, such as the statement that the energy density averag ed over a time-like curve is bounded below and the statement that the aver aged null energy on a null geodesic in Minkowski space is nonnegative.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Lampros Lamprou (Massachusetts Institute of Technology) DTSTART:20201209T160000Z DTEND:20201209T170000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/10 DESCRIPTION:Title: Inside the Hologram: The Bulk Observer's Experience\nby Lampro s Lamprou (Massachusetts Institute of Technology) as part of Online Worksh op on Qubits and Black Holes\n\n\nAbstract\nI will present a holographic f ramework for reconstructing the experience of bulk observers in AdS/CFT. I n particular\, I will show how to recover the proper time and energy distr ibution measured along bulk worldlines\, directly in the CFT via a univers al\, background-independent prescription. For an observer falling into an eternal AdS black hole\, the proposal resolves a conceptual puzzle raised by Marolf and Wall. It suffers\, however\, from the "frozen vacuum" proble m for which I will offer some preliminary comments. Notably\, the approach does not depend crucially on the asymptotic Hamiltonian and it outlines a general framework for the emergence of time.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Chris Akers (Massachusetts Institute of Technology) DTSTART:20201209T180000Z DTEND:20201209T190000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/11 DESCRIPTION:Title: Quantum Minimal Surfaces in Quantum Error-Correction\nby Chris Akers (Massachusetts Institute of Technology) as part of Online Workshop on Qubits and Black Holes\n\n\nAbstract\nWhat is the role of quantum extre mal surfaces (QES) in general quantum error-correcting codes? I will prese nt preliminary results starting to answer this question\, expanding on the previous work of Harlow\, providing necessary and sufficient conditions f or a general code to satisfy a quantum minimal surface prescription.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Geoffrey Penington (University of California\, Berkeley) DTSTART:20201209T190000Z DTEND:20201209T200000Z DTSTAMP:20260422T212934Z UID:IAS_Qubit_2020/12 DESCRIPTION:Title: Life without Pythons would be so Simple\nby Geoffrey Penington (University of California\, Berkeley) as part of Online Workshop on Qubit s and Black Holes\n\n\nAbstract\nReconstruction of bulk operators within t he causal wedge is simple to achieve using Lorentzian causal bulk dynamics . In contrast\, the only known methods for reconstructing arbitrary operat ors 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 th e bulk operator hidden behind an extremal surface (in a ‘python’s lunc h’). 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 operators c an also be simply\, and causally\, reconstructed by gradually expanding th e causal wedge using time folds with different boundary conditions.\n LOCATION:https://researchseminars.org/talk/IAS_Qubit_2020/12/ END:VEVENT END:VCALENDAR