The Effect of Sources on the Inner Horizon of Black Holes

TL;DR

This paper investigates how different matter sources, like null dust and scalar fields, influence the nature of inner horizons in black holes, revealing that scalar fields can lead to null singularities instead of space-like ones.

Contribution

It demonstrates that the type of matter source determines whether the inner horizon becomes a space-like singularity or a null singularity in black holes.

Findings

Null dust causes the inner horizon to become a space-like singularity.

Scalar fields induce null singularities on the inner horizons.

Results extend from colliding wave models to black hole interiors.

Abstract

Single pulse of null dust and colliding null dusts both transform a regular horizon into a space-like singularity in the space of colliding waves. The local isometry between such space-times and black holes extrapolates these results to the realm of black holes. However, inclusion of particular scalar fields instead of null dusts creates null singularities rather than space-like ones on the inner horizons of black holes.