alpha'^2-corrections to extremal dyonic black holes in heterotic string theory

TL;DR

This paper computes alpha'^2-corrections to the entropy of extremal dyonic black holes in heterotic string theory, confirming microscopic results for 4D cases and proposing new entropy formulas for 5D non-BPS black holes.

Contribution

It provides the first calculation of alpha'^2-corrections for 5D extremal black holes and proposes a new entropy expression for non-BPS cases supported by higher-order and AdS/CFT arguments.

Findings

Agreement with microscopic entropy for 4D black holes.

Matching with supersymmetric R^2-corrected action for 5D BPS black holes.

Proposal of a new entropy formula for 5D non-BPS black holes.

Abstract

We calculate alpha'^2-corrections to the entropy of the 5-dimensional 3-charge and the 4-dimensional 4-charge large extremal black holes using the low energy effective action of the heterotic string theory. In the 4-dimensional case, our results are in agreement with the microscopic statistical entropy both for the BPS and the non-BPS black holes. In the more interesting 5-dimensional case, where the direct microscopic stringy description is still unknown, our results for the BPS black holes are in agreement with the results obtained from the action supplemented with R^2-correction obtained by supersymmetric completion of the gravitational Chern-Simons term. This agreement does not extend to the non-BPS black holes, for which we propose a different expression for the entropy. We show that the new expression is supported by certain alpha'^3-order calculations, and by the arguments based on the AdS/CFT correspondence.