Phase transitions in geometrothermodynamic model of charged generalized-NUT black holes

TL;DR

This paper explores the thermodynamic phase transitions of charged generalized-NUT black holes using geometrothermodynamics, revealing bifurcations and stability dependencies related to curvature changes.

Contribution

It introduces a geometrothermodynamic model for charged generalized-NUT black holes and analyzes their phase transition features and stability criteria.

Findings

Series of bifurcations of pitchfork type in Gibbs free energy

Scalar Berwald curvature changes sign during phase transition

Black-hole stability depends on the sign of curvature after transition

Abstract

Modern cosmological models are constructed in the framework of thermodynamic approaches developed within a Van der Waals-Maxwell theory of the first-order phase transitions. In the present work we study a geometrothermodynamics of two-dimensional first-order phase transition with the distribution of relaxation times in a configuration space which describes a spacetime with Newman-Unti-Tamburino-like metric. We utilized the geometrothermodynamical approach to construct the model of a charged generalized-NUT black hole. We reveal following features of the black-hole phase transition: there are series of bifurcations of pitchfork type in dependences of the Gibbs free energy on the Hawking temperature, and although a scalar Berwald curvature of space changes sign in the phase transition, black-hole stability depends on sign of the curvature after the transition.