BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Netta Engelhardt (MIT) DTSTART:20221206T140000Z DTEND:20221206T150000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/1 DESCRIPTION:Title: Complexity Coarse-Graining in the Black Hole Information Probl em\nby Netta Engelhardt (MIT) as part of Workshop on Spacetime and Qua ntum Information\n\nLecture held in Wolfensohn Hall.\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Aron Wall (University of Cambridge) DTSTART:20221206T144500Z DTEND:20221206T153000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/2 DESCRIPTION:Title: Cauchy Slice Holography and the Information Paradox\nby Ar on Wall (University of Cambridge) as part of Workshop on Spacetime and Qua ntum Information\n\nLecture held in Wolfensohn Hall.\n\nAbstract\nCauchy s lice holography gives a duality between the wavefunction on a Cauchy slice and the partition function of a T2 deformed field theory. I will review this correspondence and discuss its implications for the black hole inform ation puzzle. The duality implies that postselection plays an important r ole in the method by which information escapes to the exterior region.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Jonathan Sorce (MIT) DTSTART:20221206T161500Z DTEND:20221206T170000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/3 DESCRIPTION:Title: Causality and Entanglement in Holography: The Connected Wedge Theorem Revisited\nby Jonathan Sorce (MIT) as part of Workshop on Spac etime and Quantum Information\n\nLecture held in Wolfensohn Hall.\n\nAbstr act\nOne puzzling aspect of holography is that it conjectures a duality be tween a physical theory with a single rigid causal structure (the non-grav itational "boundary theory") and one whose causal structure is state-depen dent (the gravitational "bulk theory"). In this talk\, I will explain how consistency of holographic quantum gravity can be used to constrain the en tanglement structure of a field theory state based on which sets of bounda ry points admit causal scattering in its gravitational dual. This constrai nt can be argued for directly in the boundary theory using information-the oretic reasoning\, and shown to hold in the bulk theory as a consequence o f the quantum extremal surface formula for holographic entanglement entrop y. I will also discuss how the gravitational reasoning used in this work s uggests theorems about relativistic information processing that can be pro ved directly in information theory\, without any reference to quantum grav ity. Based on 1912.05649 and 2210.00018.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Brian Swingle (Brandeis University) DTSTART:20221206T170000Z DTEND:20221206T174500Z DTSTAMP:20260404T094833Z UID:IASQubit2022/4 DESCRIPTION:Title: Holographic Measurements and Quantum Teleportation\nby Bri an Swingle (Brandeis University) as part of Workshop on Spacetime and Quan tum Information\n\nLecture held in Wolfensohn Hall.\n\nAbstract\nSpacetime wormholes can lead to surprises in black hole physics. We show that a ver y old black hole can tunnel to a white hole/firewall by emitting a large b aby universe. We study the process for a perturbed thermofield double blac k hole in Jackiw-Teitelboim (JT) gravity\, using the lowest order (genus o ne) spacetime wormhole that corresponds to single baby-universe emission. The probability for tunneling to a white hole is proportional to $t{^2}e{^ −2S}$ where t is the age of the black hole and S is the entropy of one b lack hole.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Zhenbin Yang (Stanford University) DTSTART:20221206T194500Z DTEND:20221206T203000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/5 DESCRIPTION:Title: Firewalls from Wormholes\nby Zhenbin Yang (Stanford Univer sity) as part of Workshop on Spacetime and Quantum Information\n\nLecture held in Wolfensohn Hall.\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Henry Lin (Stanford University) DTSTART:20221206T213000Z DTEND:20221206T221500Z DTSTAMP:20260404T094833Z UID:IASQubit2022/7 DESCRIPTION:Title: Algebra and Geometry from Chords\nby Henry Lin (Stanford U niversity) as part of Workshop on Spacetime and Quantum Information\n\nLec ture held in Wolfensohn Hall.\n\nAbstract\nIn double-scaled SYK\, the chor d diagrams of Berkooz et al. give rise to a bulk algebra and geometry. The algebra is a "quantum deformation" of the JT gravitational algebra that i ncludes a deformation of SL(2\,R). The growth of operator size (in particu lar\, its finite temperature\, sub-maximal Lyapunov behavior) is governed by this algebra. The deformed SL(2\,R) acts in a somewhat unusual manner o n the bulk geometry.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Ahmed Almheiri (New York University) DTSTART:20221206T221500Z DTEND:20221206T230000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/8 DESCRIPTION:Title: Path Integrals for Chords\nby Ahmed Almheiri (New York Uni versity) as part of Workshop on Spacetime and Quantum Information\n\nLectu re held in Wolfensohn Hall.\n\nAbstract\nI will describe work in progress proposing and analyzing the bulk path integral of double scaled SYK in var ious bases.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Gustavo Joaquin Turiaci (Institute for Advanced Study) DTSTART:20221207T140000Z DTEND:20221207T144500Z DTSTAMP:20260404T094833Z UID:IASQubit2022/9 DESCRIPTION:Title: Black Hole Microstate Counting from Gravity\nby Gustavo Jo aquin Turiaci (Institute for Advanced Study) as part of Workshop on Spacet ime and Quantum Information\n\nLecture held in Wolfensohn Hall.\n\nAbstrac t\nFinding a gravitational description of black hole microstates is an imp ortant problem in quantum gravity. In this talk we describe how to reprodu ce the integer number of black hole microstates using the Gibbons-Hawking gravitational path integral. This is done for a specific class of supersym metric black holes in four dimensions arising from toroidal compactificati ons of string theory: first by applying localization to the gravitational path integral that computes the index (including a careful evaluation of o ne-loop determinants)\, and second by comparing the index with the degener acy.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Bill Fefferman (The University of Chicago) DTSTART:20221207T144500Z DTEND:20221207T153000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/10 DESCRIPTION:Title: Quantum Pseudoentanglement\nby Bill Fefferman (The Univer sity of Chicago) as part of Workshop on Spacetime and Quantum Information\ n\nLecture held in Wolfensohn Hall.\n\nAbstract\nQuantum pseudorandom stat es are efficiently preparable states that are indistinguishable from truly Haar random states to an efficient observer. First defined by Ji\, Liu an d Song\, such states have found a wide variety of applications in areas su ch as quantum gravity and cryptography. A fundamental question is exactly how much entanglement is required to create such states. Haar-random state s\, as well as t-designs for t ≥ 2\, exhibit near-maximal entanglement. Here we provide the first construction of pseudorandom states with only po lylogarithmic entanglement entropy across an equipartition of the qubits\, which is the minimum possible. Our construction can be based on any one-w ay function secure against quantum attack. We additionally show that the e ntanglement in our construction is fully “tunable”\, in the sense that one can have pseudorandom states with entanglement Θ(f(n)) for any desir ed function ω(log n) ≤ f(n) ≤ O(n). More fundamentally\, our work cal ls into question to what extent entanglement is a “feelable” quantity of quantum systems. Inspired by recent work of Gheorghiu and Hoban\, we de fine a new notion which we call “pseudoentanglement”\, which are ensem bles of efficiently constructable quantum states which hide their entangle ment entropy. We show such states exist in the strongest form possible whi le simultaneously being pseudorandom states. Based on joint work with Adam Bouland\, Soumik Ghosh\, Umesh Vazirani and Zixin Zhou.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Tamra Nebabu (Stanford University) DTSTART:20221207T161500Z DTEND:20221207T170000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/11 DESCRIPTION:Title: A Generalized Protocol for Bulk Reconstruction from Generaliz ed Free Fields\nby Tamra Nebabu (Stanford University) as part of Works hop on Spacetime and Quantum Information\n\nLecture held in Wolfensohn Hal l.\n\nAbstract\nBulk reconstruction is an important step in establishing t he dictionary between boundary and bulk quantities in holographic theories . If the starting point is a quantum theory which serves as the putative b oundary model\, in what cases can one construct a bulk dual description? I will discuss recent work in which we devise a generalized protocol for co nstructing a bulk theory from any boundary model of generalized free field s. Unlike HKLL reconstruction\, the bulk geometry and dynamics are fully e mergent. I will discuss the application of our protocol to construct bulk descriptions for various SYK models beyond the conformal limit in which th ey are known to have a canonical dual. I will show evidence of that some g eometric features of the canonical bulk survive in the non-conformal limit \, and remark on the ability to extend the protocol to explore emergent bu lk physics in more general settings.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Scott Aaronson (University of Texas at Austin) DTSTART:20221207T170000Z DTEND:20221207T174500Z DTSTAMP:20260404T094833Z UID:IASQubit2022/12 DESCRIPTION:Title: Discrete Bulk Reconstruction\nby Scott Aaronson (Universi ty of Texas at Austin) as part of Workshop on Spacetime and Quantum Inform ation\n\nLecture held in Wolfensohn Hall.\n\nAbstract\nAccording to the Ad S/CFT correspondence\, the geometries of certain spacetimes are fully dete rmined by quantum states that live on their boundaries -- indeed\, by the von Neumann entropies of portions of those boundary states. This work inve stigates to what extent the geometries can be reconstructed from the entro pies in polynomial time. Bouland\, Fefferman\, and Vazirani (2019) argued that the AdS/CFT map can be exponentially complex if one wants to reconstr uct regions such as the interiors of black holes. Our main result provides a sort of converse: we show that\, in the special case of a single 1D bou ndary\, if the input data consists of a list of entropies of contiguous bo undary regions\, and if the entropies satisfy a single inequality called S trong Subadditivity\, then we can construct a graph model for the bulk in linear time. Moreover\, the bulk graph is planar\, it has O(N^2) vertices (the information-theoretic minimum)\, and it's "universal\," with only the edge weights depending on the specific entropies in question. From a comb inatorial perspective\, our problem boils down to an "inverse" of the famo us min-cut problem: rather than being given a graph and asked to find a mi n-cut\, here we're given the values of min-cuts separating various sets of vertices\, and need to find a weighted undirected graph consistent with t hose values. Our solution to this problem relies on the notion of a "bulkl ess" graph\, which might be of independent interest for AdS/CFT. We also m ake initial progress on the case of multiple 1D boundaries -- where the bo undaries could be connected wormholes -- including an upper bound of O(N^4 ) vertices whenever a planar bulk graph exists (thus putting the problem i nto the complexity class NP).\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Ronak Soni (University of Cambridge) DTSTART:20221207T190000Z DTEND:20221207T194500Z DTSTAMP:20260404T094833Z UID:IASQubit2022/13 DESCRIPTION:Title: Microstates of the 2d Non-Supersymmetric Black Hole\nby R onak Soni (University of Cambridge) as part of Workshop on Spacetime and Q uantum Information\n\nLecture held in Wolfensohn Hall.\n\nAbstract\nWe ide ntify the microstates of the non–supersymmetric\, asymptotically flat 2d black hole in the dual c=1 matrix quantum mechanics (MQM). We calculate t he partition function of the theory using Hamiltonian methods and reproduc e one of two conflicting results found by Kazakov and Tseytlin. We find th e entropy by counting states and the energy by approximately solving the S chrödinger equation. The dominant contribution to the partition function in the double-scaling limit is a novel bound state that can be considered an explicit dual of the black hole microstates. This bound state is long-l ived and evaporates slowly\, exactly like a black hole in asymptotically f lat space. Based on arXiv:2110.11493.\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Geoff Penington (University of California\, Berkeley\; Institute f or Advanced Study) DTSTART:20221207T194500Z DTEND:20221207T203000Z DTSTAMP:20260404T094833Z UID:IASQubit2022/14 DESCRIPTION:Title: The Boundary Algebras in JT Gravity\nby Geoff Penington ( University of California\, Berkeley\; Institute for Advanced Study) as par t of Workshop on Spacetime and Quantum Information\n\nLecture held in Wolf ensohn Hall.\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IASQubit2022/14/ END:VEVENT END:VCALENDAR