Dimensional reduction of 4d heterotic string black holes

TL;DR

This paper reduces 4D heterotic string black holes to 2D models to analyze their near-horizon behavior and compute their entropy, revealing duality symmetries in the reduced theory.

Contribution

It introduces a class of 2D dilaton gravity models capturing the near-horizon physics of 4D heterotic black holes and demonstrates how duality is realized in 2D.

Findings

Derived 2D models describe near-horizon, near-extremal black holes.

Computed statistical entropy matching 4D black hole entropy.

Revealed duality group realization via Weyl transformations in 2D.

Abstract

We perform the spherical symmetric dimensional reduction $4d\to2d$ of heterotic string theory. We find a class of two-dimensional (2d) dilaton gravity models that gives a general description of the near-horizon, near-extremal behavior of four-dimensional (4d) heterotic string black holes. We show that the duality group of the 4d theory is realized in two dimensions in terms of Weyl transformations of the metric. We use the 2d dilaton gravity theory to compute the statistical entropy of the near-extremal 4d, $a=1/\sqrt3$, black hole.