AdS Holography and Strings on the Horizon

TL;DR

This paper explores the microscopic origin of black hole entropy using AdS/CFT and string dualities, revealing that the boundary CFT behaves like a string on the black hole horizon, unifying different descriptions thermodynamically.

Contribution

It provides a physical picture linking the boundary conformal field theory to a string on the black hole horizon, extending the understanding of black hole entropy via holography.

Findings

Boundary CFT conforms to a string-like description.

Stringy CFT is related to a string on the stretched horizon.

Boundary theories are thermodynamically equivalent after renormalization.

Abstract

The microscopic origin of black hole entropy remains one of the more intriguing open questions in theoretical physics. A subplot in this drama is the renowned Cardy-Verlinde formula, which uses two-dimensional conformal formalism to explain the entropy of an arbitrary-dimensional black hole. In this paper, by exploiting the AdS/CFT and black hole-string dualities, we are able to provide a physical picture for this paradoxical behavior. Following a recent study by Haylo (in a dS context), we show that the dual CFT for an asymptotically AdS spacetime actually conforms to a string-like description. Moreover, we demonstrate that this stringy CFT is directly related to a string that lives on the stretched horizon of an AdS-Schwarzschild-like black hole. In fact, after an appropriate renormalization, these two boundary theories are shown to be thermodynamically equivalent.