Multi-critical Points in Black Hole Phase Transitions

TL;DR

This paper introduces the first examples of multicritical phase transitions in black hole thermodynamics, where multiple black hole phases merge at a critical point, revealing complex phase behavior similar to multicomponent systems.

Contribution

It provides explicit examples of black hole quadruple and quintuple points within non-linear electrodynamics, expanding the understanding of black hole phase structures beyond three phases.

Findings

Discovery of black hole quadruple and quintuple critical points

Demonstration of n-tuple critical points in black hole systems

Black holes exhibit multiple phases akin to multicomponent chemical systems

Abstract

We present the first examples in black hole thermodynamics of multicritical phase transitions, in which more than three distinct black hole phases merge at a critical point. Working in the context of non-linear electrodynamics, we explicitly present examples of black hole quadruple and quintuple points, and demonstrate how $n$-tuple critical points can be obtained. Our results indicate that black holes can have multiple phases beyond the three types observed so far, resembling the behaviour of multicomponent chemical systems. We discuss the interpretation of our results in the context of the Gibbs Phase Rule.