The Black Ring is Unstable

TL;DR

This paper demonstrates through numerical analysis that all black rings are unstable by identifying an unstable mode in their gravitational perturbations, extending previous findings to the entire black ring family.

Contribution

It provides the first numerical evidence that the entire black ring family, including thin and fat branches, is unstable under gravitational perturbations.

Findings

Unstable mode found in black ring perturbations

Instability exists across the entire black ring family

Supports previous theoretical instability results

Abstract

We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.