Events at https://berkeley.zoom.us/j/370438207

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Abstract: Pseudo-entropy is an interesting quantity with a simple gravity dual, which generalizes entanglement entropy such that it depends on both an initial and a final state. In this talk we start with an introduction of this new quantity explaining its basic properties. Next we will study its gravity dual. Finally, we will present recent numerical results of this quantity … Read More

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Black hole interiors share some features with cosmology: both have time dependence, singularities, horizons, and very large entropy density. In this talk I will discuss whether recent progress on understanding the black hole interior and the Page curve, based on quantum extremal islands, gives new insight into quantum cosmology.

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Topology changing processes have played a central role in recent developments in quantum gravity, and have been argued to lead to an abelian algebra of superselected observables. I will discuss one-dimensional theories of quantum gravity in this context. This invites comparison with a worldline formalism of QFT, with its non-abelian algebra of quantum fields. This apparent tension is resolved by … Read More

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ABSTRACT: I will show that the notion of quantum entanglement is notdefined for gravitationally anomalous two-dimensional theories,because they do not admit a local tensor factorization of the Hilbertspace into local Hilbert spaces. Qualitatively, the modular flowcannot act consistently and unitarily in a finite region, if there aredifferent numbers of states with a given energy traveling in the twoopposite directions. I … Read More

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Abstract: I present a proposal for how the SYK model can be realized within string theory. Starting from the matrix model description of the minimal string, I show that the partition function on a configuration of Q FZZT branes takes the form of a matrix version of the SYK model. The SYK fermions arise from open strings on brane intersections. I … Read More

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Abstract: In recent work, it was argued that quantum computations with inputs and outputs distributed in spacetime, or quantum tasks, impose constraints on entanglement in holographic theories. The resulting constraint was named the connected wedge theorem and can be verified by a direct bulk proof using focusing arguments in general relativity. In this article we extend this work to the … Read More

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Abstract: I will show that wormholes naturally arise as the gravity dual of an average over different states within a single conformal field theory. These wormholes give a simple way to diagnose how typical pure states differ from the thermal density matrix. Based on work to appear with D. Nikolakopoulou and A. Rotundo.