Properties of black hole exterior fermions in spinfoam

TL;DR

This paper investigates fermion tunneling in black hole to white hole transitions within Loop Quantum Gravity, revealing how geometric curvature influences fermion behavior and the nature of the black hole-white hole connection.

Contribution

It applies spin foam techniques to analyze fermion tunneling times and their dependence on curvature, providing new insights into black hole to white hole transition geometries.

Findings

Fermion transition times vary with Euclidean dihedral angle.

Fermions accumulate outside the black hole in negative curvature.

Fermions reach white hole exterior before black hole in positive curvature.

Abstract

We discuss fermion tunneling from the black hole exterior to white hole exterior geometry using the spin foam technique in background-independent Loop Quantum Gravity. The fermion transition time is equal, longer, or shorter than the black hole tunneling time, depending on the Euclidean dihedral angle. For a locally pinched negative curvature, fermions accumulate in the black hole exterior region where the black hole has already emerged from the white hole. Conversely, in locally stretched positive curvature, fermions reach the white hole exterior prior to the black hole, indicating an Einstein-Rosen bridge-like geometry in black hole-to-white hole bounce.