Stringy effects in black hole decay

TL;DR

This paper calculates decay rates of near-extremal black holes in string theory, incorporating stringy corrections, and finds perfect agreement with microscopic models, confirming the consistency of macroscopic and microscopic descriptions.

Contribution

It introduces a method to compute stringy corrections to black hole decay rates and demonstrates their agreement with microscopic entropy calculations in specific string theory models.

Findings

Stringy corrections match microscopic entropy calculations.

Zero energy scattering cross section equals four times the Wald entropy.

Method applies to near-extremal black holes in N=4 string theory.

Abstract

We compute the low energy decay rates of near-extremal three(four) charge black holes in five(four) dimensional N=4 string theory to sub-leading order in the large charge approximation. This involves studying stringy corrections to scattering amplitudes of a scalar field off a black hole. We adapt and use recently developed techniques to compute such amplitudes as near-horizon quantities. We then compare this with the corresponding calculation in the microscopic configuration carrying the same charges as the black hole. We find perfect agreement between the microscopic and macroscopic calculations; in the cases we study, the zero energy limit of the scattering cross section is equal to four times the Wald entropy of the black hole.