High Energy Theory Seminar

How can one define a causal structure or an event horizon in a stringy geometry? In this talk, I will show that this can be done by using the operator algebras of the holographic dual. In particular, I will introduce a new quantity, dubbed "depth parameter", which can be computed in terms of the algebraic structure of the large N boundary theory, and measures a notion of radial extension for the bulk dual of a boundary subregion that still makes sense away from strong coupling. There is an emergent stringy bifurcate horizon if and only if the depth parameter is infinite, and the precise value of this depth parameter also allows to diagnose potential violations of the equivalence principle in the bulk at nonzero string length. The depth parameter can be computed in various examples of interest, in particular, it can be used to argue that a sharp horizon structure emerges in the bulk dual of N=4 Super-Yang—Mills for all nonzero values of the 't Hooft coupling. This talk is based on a paper to appear in collaboration with Hong Liu.

The talk is in 469 Lauritsen.

Contact [email protected] for Zoom information.