Statistical Entropy of Nonextremal Four-Dimensional Black Holes and U-Duality

TL;DR

This paper explores the microscopic states in string theory responsible for the entropy of near-extremal and non-extremal rotating four-dimensional black holes, emphasizing duality invariance and entropy matching.

Contribution

It identifies the string theory states responsible for black hole entropy and extends entropy formulas to non-extremal, non-rotating black holes using duality invariance.

Findings

Exact match of Bekenstein-Hawking entropy for non-extremal black holes

Extension of near-extremal entropy formulas to far-from-extremal cases

Duality invariant formulation of black hole entropy

Abstract

We identify the states in string theory which are responsible for the entropy of near-extremal rotating four-dimensional black holes in $N=8$ supergravity. For black holes far from extremality (with no rotation), the Bekenstein-Hawking entropy is exactly matched by a mysterious duality invariant extension of the formulas derived for near-extremal black holes states.