Black Hole Tunneling Entropy and the Spectrum of Gravity

TL;DR

This paper applies the tunneling approach to black hole entropy in quantum gravity, revealing that the traditional area entropy accounts for only a tiny part of the black hole degeneracy, which is infinite due to quantum effects.

Contribution

It demonstrates that black hole entropy derived from tunneling accounts for a small fraction of degeneracy, which is infinite due to quantum gravity effects extending the wave function.

Findings

Area entropy accounts for a tiny fraction of degeneracy

Black hole remnants are infinitely degenerate 'planckons'

Quantum gravity introduces an infinite Hilbert space at the Planck scale

Abstract

The tunneling approach for entropy generation in quantum gravity is applied to black holes. The area entropy is recovered and shown to count only a tiny fraction of the black hole degeneracy. The latter stems from the extension of the wave function outside the barrier. In fact the semi-classical analysis leads to infinite degeneracy. Evaporating black holes leave then infinitely degenerate "planckons" remnants which can neither decay into, nor be formed from, ordinary matter in a finite time. Quantum gravity opens up at the Planck scale into an infinite Hilbert space which is expected to provide the ultraviolet cutoff required to render the theory finite in the sector of large scale physics.