Black hole entropy, curved space and monsters

TL;DR

This paper explores the microscopic origins of black hole entropy, introduces 'monsters' as pathological configurations exceeding entropy bounds, and suggests black hole microstates relate to smaller black holes and matter, excluding monsters.

Contribution

It identifies and analyzes 'monster' configurations that challenge entropy bounds, refining the understanding of black hole microstates and entropy limits in curved space.

Findings

Monsters have entropy greater than the area in Planck units.

Excluding monsters, the entropy of matter is bounded by $S < A^{3/4}$.

Black hole microstates are related to smaller black holes and matter configurations.

Abstract

We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than their area in Planck units. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter $S < A^{3/4}$. This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states.