String-Loop Corrections Versus Non-Extremality

TL;DR

This paper analyzes how string-loop corrections affect magnetic black-hole solutions, showing that such corrections can shift the horizon and make the extremal solution resemble a non-extremal one, with implications for black hole thermodynamics.

Contribution

It provides an analytical solution for loop-corrected magnetic black holes and compares their properties with non-extremal solutions, highlighting the effects of string-loop corrections.

Findings

Loop corrections shift the horizon location.

Loop-corrected extremal black holes resemble non-extremal solutions.

Thermodynamic properties are affected by loop corrections.

Abstract

We discuss a magnetic black-hole solution to the equations of motion of the string-loop-corrected effective action. At the string-tree level, this solution is the extremal magnetic black hole described by the "chiral null model." In the extremal case, the string-loop correction is constant, and this fact is used to analytically solve the loop-corrected equations of motion. In distinction to the tree-level solution, the resulting loop-corrected solution has the horizon at a finite distance from the origin; its location is a function of the loop correction. The loop-corrected configuration is compared with a string-tree-level non-extremal magnetic black hole solution which also has the horizon at a finite distance from the origin. We find that for an appropriate choice of the free parameters of solutions, the loop-corrected magnetic black hole can be approximated by a tree-level non-extremal solution. We compare the thermodynamic properties of the loop-corrrected and non-extremal solutions.