The Attractor of Evaporating Reissner-Nordstr\"om Black Holes

TL;DR

This paper investigates the attractor behavior in the evolution of evaporating Reissner-Nordström black holes, revealing that the attractor is characterized by equal mass and charge loss rates, and exploring its relation to thermodynamic properties.

Contribution

It provides a detailed analysis of the attractor in evaporating Reissner-Nordström black holes, clarifying its nature and relation to specific heat and charge-to-mass ratio.

Findings

The attractor is characterized by equal mass and charge loss rates.

The attractor is not necessarily related to the specific heat in general.

Part of the attractor lies near the boundary where specific heat changes sign.

Abstract

Hiscock and Weems showed that there is an attractor behavior in the evolution of asymptotically flat Reissner-Nordstr\"om black hole under Hawking evaporation. If the initial charge-to-mass ratio $Q/M$ of the black hole is relatively small, then the ratio first increases until the black hole hits the attractor, and then starts to discharge towards the Schwarzschild limit. Sufficiently charged black holes, on the other hand, simply discharge steadily towards the Schwarzschild limit. In this work we further investigate the nature of the attractor, and found that it is characterized by the mass loss rate being equal to the charge loss rate. The attractor is not necessarily related to the specific heat in a general evaporating black hole spacetime, but for the Reissner-Nordstr\"om case part of the attractor lies very close to the boundary of the region where specific heat changes sign.