I will describe a construction of algebras of observables associated with local subregions in quantum gravity in the small G_N limit.  This algebra consists of operators dressed to a semiclassical observer degree of freedom which serves as an anchor defining the subregion.  I will argue that properly implementing the gravitational constraints on this algebra results in a type II von Neumann algebra, which possesses a well-defined notion of entropy.  Up to a state-independent constant, this entropy agrees with the UV-finite generalized entropy of the subregion, consisting of a Bekenstein-Hawking area term and a bulk entropy term.  This gives an algebraic interpretation of the generalized entropy, and provides a number of tools for investigating aspects of semiclassical gravitational entropy, including the generalized second law, the quantum focusing conjecture, and the quantum extremal surface prescription in holography.  

报告人简介

Antony Speranza is a postdoctoral fellow at the University of Illinois, Urbana-Champaign, working on applications of entanglement entropy and von Neumann algebras to quantum gravity.  He completed his Ph.D. at the University of Maryland, College Park, under the supervision of Ted Jacobson, and previously was a postdoctoral fellow at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario. 

邀请人

吴洁强 副研究员