Phase transitions of the BTZ black hole in new massive gravity

TL;DR

This paper explores the thermodynamic phase transitions of BTZ black holes in new massive gravity, revealing a Hawking-Page transition for certain parameters and an inverse transition for others, highlighting novel gravitational phenomena.

Contribution

It provides a detailed analysis of phase transitions in BTZ black holes within new massive gravity, identifying conditions for Hawking-Page and inverse transitions.

Findings

Hawking-Page transition occurs for m^2ℓ^2 > 1/2.

Inverse Hawking-Page transition is possible for m^2ℓ^2 < 1/2.

Transition behaviors depend on the mass parameter and curvature radius.

Abstract

We investigate thermodynamics of the BTZ black hole in new massive gravity explicitly. For $m^2\ell^2>1/2$ with $m^2$ the mass parameter of fourth-order terms and $\ell^2$ AdS$_3$ curvature radius, the Hawking-Page phase transition occurs between the BTZ black hole and AdS (thermal) soliton. For $m^2\ell^2<1/2$, however, this transition unlikely occurs but a phase transition between the BTZ black hole and the massless BTZ black hole is possible to occur. We may call the latter as the inverse Hawking-Page phase transition and this transition is favored in the new massive gravity.