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
The full bulk path integral in a Lorentzian formulation of holography includes metrics that violate boundary causality. This leads to the following puzzle: The commutator of two field theory operators at spacelike-separated points on the boundary must vanish. However, if these points are causally related in a bulk metric, then the bulk calculation of the commutator will be nonzero. It … Read More
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
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
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.
Abstract: I will describe a Hayden & Preskill like setup for both maximally chaotic and submaximally chaotic quantum field theories by acting on the vacuum with an operator in a Rindlerlike wedge R, and transferring a small subregion I of R to the other wedge. The chaotic scramblingdynamics of the QFT Rindler time evolution reveals the information in the other … Read More
Recent developments have led to a breakthrough in our understanding of the evaporation of black holes in very special systems: gravity in a box, coupled to an external bath. To what extend these considerations apply to generic black holes is a point of debate. In this talk we will demonstrate that one of the main ingredients in these calculations, the … Read More
Haar integrals over the unitary group contain subleading terms that are needed for unitarity. We study analogous effects in the time evolution operators of JT grav- ity and Brownian SYK. In JT gravity with bulk matter we find an explanation for the first subleading terms, and in Brownian SYK we find configurations that can explain the full series. An important … Read More
Abstract: We discuss the resolution of the factorization puzzle in AdS/CFT in the context of a simple version of the SYK model. (Joint work with Phil Saad, Douglas Stanford and Shunyu Yao.)