$Q-\Phi$ criticality in the extended phase space of $(n+1)$-dimensional RN-AdS black holes

TL;DR

This paper investigates the thermodynamic phase structure of higher-dimensional RN-AdS black holes using Maxwell's equal area law, focusing on the critical behavior in an extended phase space with temperature, charge, and potential as parameters.

Contribution

It introduces a detailed analysis of phase equilibrium in $(n+1)$-dimensional RN-AdS black holes considering $T$, $Q$, and $\Phi$ as state variables, expanding understanding beyond traditional phase transition studies.

Findings

Boundary of two-phase coexistence region mapped

Isotherm and isopotential lines analyzed

Theoretical foundation for black hole phase transitions established

Abstract

In order to achieve a deeper understanding of gravity theories, it is important to further investigate the thermodynamic properties of black hole at the critical point, besides the phase transition and critical behaviors. In this paper, by using Maxwell's equal area law, we choose $T,Q,\Phi$ as the state parameters and study the phase equilibrium problem of general $(n+1)$-dimensional RN-AdS black holes thermodynamic system. The boundary of the two-phase coexistence region and its isotherm and isopotential lines are presented, which may provide theoretical foundation for studying the phase transition and phase structure of black hole systems.