Thermodynamic properties of massive dilaton black holes II

TL;DR

This paper numerically reanalyzes thermodynamic properties of massive dilaton black holes, revealing critical mass thresholds that influence black hole extremality and temperature behavior, extending understanding of black hole solutions in Einstein-Maxwell-dilaton systems.

Contribution

It provides a detailed numerical analysis of how the dilaton mass affects black hole thermodynamics and identifies critical mass values that alter solution properties.

Findings

Thermodynamic properties change at a critical dilaton mass.

Black holes become extremal for certain mass ranges.

Hawking temperature approaches that of massless dilaton black holes as horizon shrinks.

Abstract

We numerically reanalyze static and spherically symmetric black hole solutions in an Einstein-Maxwell-dilaton system with a dilaton potential $m_{d}^{2}\phi^{2}$. We investigate thermodynamic properties for various dilaton coupling constants and find that thermodynamic properties change at a critical dilaton mass $m_{d,crit}$. For $m_{d}\geq m_{d,crit}$, the black hole becomes an extreme solution for a nonzero horizon radius $r_{h,ex}$ as the Reissner-Nordstr\"om black hole. However, if $m_{d}$ is nearly equal to $m_{d,crit}$, there appears a solution of smaller horizon radius than $r_{h,ex}$. For $m_{d}<m_{d,crit}$, a solution continues to exist until the horizon approaches zero. The Hawking temperature in the zero horizon limit resembles that of a massless dilaton black hole for arbitrary dilaton coupling constant.