Mass inflation inside non-Abelian black holes

TL;DR

This paper investigates the internal structure of non-Abelian black holes, revealing that mass inflation occurs instead of a Cauchy horizon, with notable differences depending on the presence of a Higgs field.

Contribution

It demonstrates that non-Abelian black holes do not form inner horizons and introduces the concept of mass inflation inside these black holes, highlighting the effects of the Higgs field.

Findings

Mass inflation replaces the Cauchy horizon in non-Abelian black holes.

Without a Higgs field, mass inflation occurs cyclically with violent explosions.

Presence of a Higgs field prevents mass inflation cycles.

Abstract

The interior geometry of static, spherically symmetric black holes of the Einstein-Yang-Mills-Higgs theory is analyzed. It is found that in contrast to the Abelian case generically no inner (Cauchy) horizon is formed inside non-Abelian black holes. Instead the solutions come close to a Cauchy horizon but then undergo an enormous growth of the mass function, a phenomenon which can be termed `mass inflation' in analogy to what is observed for perturbations of the Reissner-Nordstr{\o}m solution. A significant difference between the theories with and without a Higgs field is observed. Without a Higgs field the YM field induces repeated cycles of massinflation -- taking the form of violent `explosions' -- interrupted by quiescent periods and subsequent approaches to an almost Cauchy horizon. With the Higgs field no such cycles occur. Besides the generic solutions there are non-generic families with a Schwarzschild, Reissner-Nordstr{\o}m and a pseudo Reissner-Nordstr{\o}m type singularity at $r=0$.