Thermodynamical phases of a regular SAdS black hole

TL;DR

This paper analyzes the thermodynamical phases and stability of regular black holes in AdS5, revealing phase transitions and the dominance of near-extremal black holes at low temperatures depending on a coupling parameter.

Contribution

It introduces a detailed study of thermodynamical phases of regular AdS black holes, highlighting the effects of a coupling constant on phase transitions and stability, which was not previously explored.

Findings

Existence of a critical coupling constant L_{inf}=0.2 affecting phase behavior.

Presence of first order phase transitions in the weak-coupling regime.

At low temperatures, near-extremal black holes dominate over radiation.

Abstract

This paper studies the thermodynamical stability of regular BHs in AdS5 background. We investigate off-shell free energy of the system as a function of temperature for different values of a "coupling constant" L=4 theta/l^2, where the cosmological constant is Lambda = -3/l^2 and \sqrt{theta} is a "minimal length". The parameter L admits a critical value, L_{inf}=0.2, corresponding to the appearance of an inflexion point in the Hawking temperature. In the weak-coupling regime L < L_{inf}, there are first order phase transitions at different temperatures. Unlike the Hawking-Page case, at temperature 0\le T \le T_{min} the ground state is populated by "cold" near-extremal BHs instead of a pure radiation. On the other hand, for L \g L_{inf} only large, thermodynamically stable, BHs exist.