Microscopic origin of the entropy of astrophysical black holes

TL;DR

This paper constructs a family of black hole microstates in Minkowski spacetime, demonstrating that their overlaps lead to a Hilbert space dimension matching the Bekenstein-Hawking entropy, thus explaining its statistical origin.

Contribution

It introduces a new class of microstates with semiclassical descriptions and shows how quantum wormholes ensure their universal overlaps, linking microstate counting to black hole entropy.

Findings

Microstates span a Hilbert space with dimension matching the horizon area.

Quantum wormholes cause exponentially small overlaps between microstates.

The results explain the statistical origin of black hole entropy.

Abstract

We construct an infinite family of microstates for black holes in Minkowski spacetime which have effective semiclassical descriptions in terms of collapsing dust shells in the black hole interior. Quantum mechanical wormholes cause these states to have exponentially small, but universal, overlaps. We show that these overlaps imply that the microstates span a Hilbert space of log dimension equal to the event horizon area divided by four times the Newton constant, explaining the statistical origin of the Bekenstein-Hawking entropy.