Thermodynamics and Phase Structure of an Einstein-Maxwell-scalar Model in Extended Phase Space

TL;DR

This paper investigates the thermodynamics and phase transitions of Einstein-Maxwell-scalar black holes in extended phase space, revealing reentrant phase transitions involving zeroth- and second-order transitions in various ensembles.

Contribution

It introduces a detailed analysis of phase structures and reentrant phase transitions in Einstein-Maxwell-scalar black holes with non-minimal coupling.

Findings

Reentrant phase transitions observed in both canonical and grand canonical ensembles.

Identification of zeroth- and second-order phase transitions.

Derivation of thermodynamic relations for the EMS black hole solutions.

Abstract

In this paper, we study thermodynamics and phase structure of asymptotically AdS hairy and Reissner-Nordstr\"{o}m-AdS (RNAdS) black holes in the extended phase space, where the cosmological constant is interpreted as a thermal pressure. The RNAdS and hairy black holes are black hole solutions of an Einstein-Maxwell-scalar (EMS) model with a non-minimal coupling between the scalar and electromagnetic fields. The Smarr relation, the first law of thermodynamics and the free energy are derived for black hole solutions in the EMS model. Moreover, the phase structure of the RNAdS and hairy black holes is investigated in canonical and grand canonical ensembles. Interestingly, RNAdS BH/hairy BH/RNAdS BH reentrant phase transitions, consisting of zeroth-order and second-order phase transitions, are found in both ensembles.