Extremal black holes that are not extremal: maximal warm holes

TL;DR

This paper explores a novel class of charged black holes that develop scalar hair at maximum charge, resulting in non-extremal, warm black holes with nonzero temperature, impacting understanding of black hole evaporation.

Contribution

It introduces a family of hairy black holes with maximum charge that are not extremal, challenging traditional extremality concepts in black hole physics.

Findings

Maximum charge black holes are nonsingular and hairy.

These black holes have nonzero Hawking temperature.

Implications for black hole evaporation are discussed.

Abstract

We study a family of four-dimensional, asymptotically flat, charged black holes that develop (charged) scalar hair as one increases their charge at fixed mass. Surprisingly, the maximum charge for given mass is a nonsingular hairy black hole with nonzero Hawking temperature. The implications for Hawking evaporation are discussed.