Thermodynamics of third order Lovelock anti-de Sitter black holes revisited

TL;DR

This paper revisits the thermodynamics of third order Lovelock anti-de Sitter black holes, analyzing their stability and phase structure across different dimensions and horizon topologies.

Contribution

It provides a detailed stability analysis of third order Lovelock black holes in AdS space, revealing new phases and stability conditions depending on dimension and Lovelock coefficients.

Findings

Black holes with $k=-1$ are thermodynamically stable for all sizes.

An intermediate unstable phase exists for $k=1$ in 7 dimensions.

New unstable small black hole phase appears in 8D for certain Lovelock coefficients.

Abstract

We compute the mass and the temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient $\alpha_2<0$ in anti-de Sitter space and perform the stability analysis of topological black holes. When $k=-1$, the third order Lovelock black holes are thermodynamically stable for the whole range $r_+$. When $k=1$, we found that the black hole has an intermediate unstable phase for $D=7$. In eight dimensional spacetimes, however, a new phase of thermodynamically unstable small black holes appears if the coefficient $\tilde{\alpha}$ is under a critical value. For $D\geq 9$, black holes have similar the distributions of thermodynamically stable regions to the case where the coefficient $\tilde{\alpha}$ is under a critical value for $D=8$. It is worth to mention that all the thermodynamic and conserved quantities of the black holes with flat horizon don't depend on the Lovelock coefficients and are the same as those of black holes in general gravity.