Fermion Tunneling from Dynamical Horizons

TL;DR

This paper investigates fermion emission from evolving black hole horizons using the Hamilton-Jacobi tunneling method, revealing insights into surface gravity, temperature, and black hole stability during slow evolution.

Contribution

It applies the tunneling method to dynamical horizons, showing how surface gravity defines temperature and indicating black hole semi-classical instability.

Findings

Surface gravity determines temperature during slow evolution.

Black holes are semi-classically unstable even without bosonic fields.

The method applies to black holes and point masses in expanding universes.

Abstract

The instability against emission of fermionic particles by the trapping horizon of an evolving black hole is analyzed using the Hamilton-Jacobi tunneling method. This method automatically selects one special expression for the surface gravity of a changing horizon. The results also apply to point masses embedded in an expanding universe. As a bonus of the tunneling method, we gain the insight that the surface gravity still defines a temperature parameter as long as the evolution is sufficiently slow that the black hole pass through a sequence of quasi-equilibrium states, and that black holes should be semi-classically unstable even in a hypothetical world without bosonic fields.