Charged black holes in effective string theory

TL;DR

This paper explores how string theory modifications, including Yang-Mills and Gauss-Bonnet corrections, alter the properties and thermodynamics of charged black holes, revealing new features like maximum temperature and modified evaporation.

Contribution

It introduces a perturbative analysis of charged dilatonic black holes with string corrections, highlighting novel thermodynamic behaviors not seen in classical solutions.

Findings

Black hole temperature exhibits a maximum for high magnetic charge.

Hawking evaporation law is modified at a classical level due to string effects.

Finite mass black holes can have zero temperature, indicating stable remnants.

Abstract

We investigate the qualitative new features of charged dilatonic black holes which emerge when both the Yang-Mills and Gauss-Bonnet curvature corrections are included in the effective action. We consider perturbative effects by an expansion up to second order in the inverse string tension on the four dimensional Schwarzschild background and determine the backreaction. We calculate the thermodynamical functions and show that for magnetic charge above a critical value, the temperature of the black hole has a maximum and goes to zero for a finite value of the mass. This indicates that the conventional Hawking evaporation law is modified by string theory at a classical level.