Analogous supercritical crossovers in black holes and water

TL;DR

This paper explores supercritical phase transitions in black holes, revealing universal scaling laws and analogies with water's phase behavior, enhancing understanding of black hole thermodynamics beyond the critical point.

Contribution

It establishes a refined supercritical phase diagram for black holes, identifying crossover lines and verifying universal scaling laws in both standard and extended thermodynamic frameworks.

Findings

Universal scaling laws of crossover lines verified.

Analogies between black hole and water phase diagrams demonstrated.

Refined phase diagram characterizing black hole phases established.

Abstract

We investigate the supercritical crossovers for black hole thermodynamics in the supercritical regime beyond the critical point, where small and large black holes are indistinguishable from the conventional viewpoint. We establish a refined supercritical phase diagram that comprehensively characterizes small, large, and indistinguishable black hole phases, whose boundaries are defined by two supercritical crossover lines. The universal scaling laws of the two crossover lines are fully verified using black hole thermodynamics in both the standard consideration and the extended thermodynamic phase space by treating the cosmological constant as a thermodynamic pressure. Remarkable analogies are observed when the supercritical phase diagrams of the two frameworks of black holes are compared to those corresponding to liquid-gas and liquid-liquid phase transitions. The present study can be extended to a variety of more complicated black hole backgrounds and provide valuable insights into the fundamental nature of black hole thermodynamics.