Black Hole Superradiance in the Presence of Lorentz Symmetry Violation

TL;DR

This study investigates how Lorentz symmetry violation affects superradiance and instability in rotating black holes, revealing that Lorentz-violating parameters can enhance or suppress these phenomena.

Contribution

It introduces the impact of Lorentz symmetry breaking on black hole superradiance and instability, providing new bounds and insights in Einstein-bumblebee gravity.

Findings

Lorentz violation with negative parameter enhances superradiance.

Positive Lorentz violation weakens superradiance.

Negative Lorentz violation increases instability parameter space.

Abstract

In this paper we consider the massive scalar perturbation on the top of a small spinning-like black hole in context of Einstein-bumblebee modified gravity in order to probe the role of spontaneous Lorentz symmetry breaking on the superradiance scattering and corresponding instability. We show that at the low-frequency limit of the scalar wave the superradiance scattering will be enhanced with the Lorentz-violating parameter $\alpha<0$ and will be weakened with $\alpha>0$. Moreover, by addressing the black hole bomb issue, we extract an improved bound in the instability regime indicating that $\alpha<0$ increases the parameter space of the scalar field instability, while $\alpha>0$ decreases it.