Radiation from a class of string theoretic black holes

TL;DR

This paper compares string theoretic and semiclassical calculations of low-energy scalar emission from higher-dimensional charged black holes, finding agreement at leading order but discrepancies at higher orders except in specific cases.

Contribution

It demonstrates that string and semiclassical methods agree at leading order for certain black holes, revealing limits of the correspondence at higher orders.

Findings

Agreement at lowest order when Bekenstein-Hawking formula holds

Disagreement at next order except for specific dimensions and charges

Effective central charge c_{eff}=6 for all D

Abstract

The emission of a scalar with low energy $\omega$, from a $D (4\le D\le 8 )$ dimensional black hole with n charges is studied in both string and semiclassical calculations. In the lowest order in $\omega$, the weak coupling string and semiclassical calculations agree provided that the Bekenstein--Hawking formula is valid and the effective central charge $c_{eff}=6$ for any D. When the next order in $\omega$ is considered however, there is no agreement between the two schemes unless D=5, n=3 or D=4, n=4.