Gregory-Laflamme and Superradiance encounter Black Resonator Strings

TL;DR

This paper introduces black resonator strings, novel non-axisymmetric black string solutions with a helical symmetry, branching from superradiant instabilities and having higher entropy than traditional Myers-Perry black strings.

Contribution

The authors construct and analyze black resonator strings with unique symmetries, expanding the understanding of superradiant instabilities and their resulting solutions in higher-dimensional gravity.

Findings

Black resonator strings have higher entropy than Myers-Perry black strings at coexistence energies.

Black resonator strings possess a helical Killing vector field and break several symmetries.

Kaluza-Klein geons are constructed as horizonless solutions sharing symmetries with black resonator strings, but are separate solutions.

Abstract

We construct novel black strings that are neither time-translation invariant, nor axisymmetric, nor translationally invariant in the string direction, but nevertheless have a helical Killing vector field. These solutions branch from the superradiant instability of $D=6$ Myers-Perry black strings with equal angular momenta. We coin these solutions as {\it black resonator strings} and we find that they have more entropy than Myers-Perry black strings for the energies and angular momenta where both solutions coexist. We also construct Kaluza-Klein geons, which share the symmetries of black resonator strings, but are horizonless. Unlike in other superradiant systems, Kaluza-Klein geons are not the horizonless limit of black resonator strings and are instead entirely separate solutions.