Thermodynamic instability of doubly spinning black objects

TL;DR

This paper analyzes the thermodynamic stability of doubly spinning black objects, revealing that black rings are unstable and exploring phase transitions and ensemble relations in higher-dimensional black hole configurations.

Contribution

It provides the first detailed thermodynamic stability analysis of doubly spinning black rings and clarifies the relation between microcanonical and grand canonical ensembles.

Findings

Doubly spinning black rings are thermodynamically unstable.

Identified phase transitions between black string and membrane phases.

Established a connection between microcanonical and grand canonical ensemble stability.

Abstract

We investigate the thermodynamic stability of neutral black objects with (at least) two angular momenta. We use the quasilocal formalism to compute the grand canonical potential and show that the doubly spinning black ring is thermodynamically unstable. We consider the thermodynamic instabilities of ultra-spinning black objects and point out a subtle relation between the microcanonical and grand canonical ensembles. We also find the location of the black string/membrane phases of doubly spinning black objects.