Black Hole Entropy from Loop Quantum Gravity

TL;DR

This work argues that for a (macroscopically) Schwarzschild black hole this ensemble is formed by horizons with the same area, and obtains a statistical entropy proportional to the area, as in the Bekenstein-Hawking formula.

Abstract

We argue that the statistical entropy relevant for the thermal interactions of a black hole with its surroundings is (the logarithm of) the number of quantum microstates of the hole which are distinguishable from the hole's exterior, and which correspond to a given hole's macroscopic configuration. We compute this number explicitly from first principles, for a Schwarzschild black hole, using nonperturbative quantum gravity in the loop representation. We obtain a black hole entropy proportional to the area, as in the Bekenstein-Hawking formula.