Extremal Bifurcations of Rotating AdS$_4$ Black Holes

TL;DR

This paper investigates the possibility of extremal rotating AdS$_4$ black holes bifurcating into smaller black holes, demonstrating that such a process can be consistent with the second law of thermodynamics.

Contribution

It provides a theoretical analysis showing that bifurcations of extremal rotating AdS$_4$ black holes can occur without violating thermodynamic principles.

Findings

Bifurcation processes can satisfy the second law of thermodynamics.

Rotating near-extremal black holes may emit smaller black holes.

Theoretical framework supports bifurcation mechanisms in AdS$_4$ black holes.

Abstract

The Weak Gravity Conjecture arises from the assertion that all extremal black holes, even those which are "classical" in the sense of being very massive, must decay by quantum-mechanical emission of particles or smaller black holes. This is interesting, because some observed astrophysical black holes are on the brink of being extremal -- $\,$ though this is due to rapid rotation rather than a large electric or magnetic charge. The possibility that rotating near-extremal black holes might, in addition to radiating spinning particles, also bifurcate by emitting smaller black holes, has attracted much attention of late. There is, however, a basic question to be answered here: can such a bifurcation be compatible with the second law of thermodynamics? This is by no means clear. Here we show that, if there is indeed such a mechanism for bifurcations of AdS$_4$-Kerr-Newman black holes, then this process can in fact satisfy the second law.