Some remarks on black hole temperature and the second law of thermodynamics

TL;DR

This paper proposes a formulation of the second law of thermodynamics involving black holes, introducing a Carnot coefficient dependent on black hole mass, to analyze heat extraction efficiency.

Contribution

It introduces a novel formulation of the second law using black hole thermodynamics and derives a simple mass-dependent Carnot coefficient.

Findings

Carnot coefficient expressed as a simple function of black hole mass

Formulation of the second law in the context of black hole thermodynamics

Analysis of heat extraction efficiency from black holes

Abstract

I present a formulation of the second law of thermodynamics in the presence of black holes which makes use of the efficiency of an ideal machine extracting heat cyclically from a black hole. The Carnot coefficient is found and it is shown to be a simple function of the mass.