Entropy Count for Extremal Three-Dimensional Black Strings

TL;DR

This paper calculates the entropy of extremal three-dimensional black strings using conformal field theory methods, confirming it matches the Bekenstein-Hawking entropy, and explores their supersymmetry properties.

Contribution

It provides a novel computation of black string entropy via CFT techniques and demonstrates supersymmetry preservation in an embedding within supergravity.

Findings

Entropy matches Bekenstein-Hawking formula

Black strings preserve 1/4 of supersymmetries

Embedding in supergravity is established

Abstract

We compute the entropy of extremal black strings in three dimensions, using Strominger's approach to relate the Anti-de-Sitter near-horizon geometry and the conformal field theory at the asymptotic infinity of this geometry. The result is identical to the geometric Bekenstein-Hawking entropy. We further discuss an embedding of three-dimensional black strings in $N=1 D=10$ supergravity and demonstrate that the extremal strings preserve 1/4 of supersymmetries.