Extreme black hole entropy obtained in an operational approach

TL;DR

This paper investigates the entropy of extreme black holes using an operational approach, revealing that entropy can be stored in material and varies with material states for different black hole types.

Contribution

It introduces an operational method to analyze black hole entropy, showing different entropy behaviors for two kinds of extreme black holes based on material states.

Findings

Entropy of the first kind of extreme black hole depends on material states.

Entropy of the second kind of extreme black hole is independent of material states.

Relations between entropy results and black hole stability are discussed.

Abstract

The entropy of anti-de Sitter Reissner-Nordstrom black hole is found to be stored in the material which gathers to form it and equals to $A/4$ regardless of material states. Extending the study to two kinds of extreme black holes, we find different entropy results for the first kind of extreme black hole due to different material states. However for the second kind of extreme black hole the results of entropy are uniform independently of the material states. Relations between these results and the stability of two kinds of extreme black holes have been addressed.