Extremal black holes as exact string solutions

TL;DR

This paper demonstrates that the extremal electrically charged black hole solution in string theory is exact to all orders in alpha prime when viewed through a Kaluza-Klein framework, based on its derivation from a five-dimensional exact background.

Contribution

It shows that the extremal black hole solution is an exact string solution to all orders in alpha prime via dimensional reduction from a five-dimensional background.

Findings

The extremal black hole solution is exact to all orders in alpha prime.

The solution can be derived from a five-dimensional exact string background.

The approach uses Kaluza-Klein dimensional reduction.

Abstract

We show that the leading order solution describing an extremal electrically charged black hole in string theory is, in fact, an exact solution to all orders in $\a'$ when interpreted in a Kaluza-Klein fashion. This follows from the observation that it can be obtained via dimensional reduction from a five dimensional background which is proved to be an exact string solution.