The Boulware State and the Generalised Second Law of Thermodynamics

TL;DR

This paper demonstrates that the Boulware vacuum state is appropriate for the interior of a box lowered into a Schwarzschild black hole and discusses related entropy bounds, contributing to understanding black hole thermodynamics.

Contribution

It identifies the Boulware state as the correct vacuum inside a lowered box and relates this to entropy bounds, extending prior work on black hole thermodynamics.

Findings

Boulware state matches the stress-energy inside the box

Supports Bekenstein's entropy bound conjecture

Aligns with Unruh and Wald's results on stress-energy

Abstract

We show that the appropriate vacuum state for the interior of a box with reflecting walls being lowered adiabatically into a Schwarzschild black hole is the Boulware state. This is concordant with the results of Unruh and Wald, who used a different approach to obtain the stress-energy inside the box. Some comments about an entropy bound for ordinary matter, as first conjectured by Bekenstein, are presented.