An instability of the Reissner-Nordstrom solution and new hairy black holes in d=5 dimensions

TL;DR

This paper demonstrates that the five-dimensional Reissner-Nordstrom black hole becomes unstable under Einstein--Yang-Mills--Chern-Simons theory, leading to new stable black hole solutions with non-Abelian fields, finite mass, and diverse asymptotics.

Contribution

It introduces a new class of hairy black holes in five dimensions arising from instability analysis, highlighting the role of the Chern-Simons term in their finite mass.

Findings

Reissner-Nordstrom black hole becomes unstable in d=5 with Yang-Mills--Chern-Simons theory.

Existence of new black hole solutions with non-Abelian magnetic fields.

Solutions have finite mass and are valid in Minkowski and (A)dS backgrounds.

Abstract

The d=5 Reissner-Nordstrom black hole becomes unstable when considered as a solution of Einstein--Yang-Mills--Chern-Simons theory. The existence of a marginally stable mode gives rise to a new branch of black holes with non-Abelian magnetic fields outside the horizon. These solutions carry a nonzero electric charge and have finite mass. We argue that these features manifest themselves both for Minkowski and (Anti-)de Sitter asymptotics. The properties of solutions in a de Sitter background are new to the present work and are emphasised. All solutions constructed have finite mass by virtue of the presence of the Chern-Simons term, which in d=5 plays the role of a higher order term scaling appropriately for this purpose.