Perturbations and quasi-normal modes of black holes in Einstein-Aether theory

TL;DR

This paper introduces a new numerical method for calculating black hole quasi-normal modes applicable to solutions with numerically known potentials, and applies it to Einstein-Aether black holes revealing increased oscillation frequencies and damping rates.

Contribution

The paper presents a novel method for computing quasi-normal modes in black holes with numerically known potentials, specifically applied to Einstein-Aether theory.

Findings

Einstein-Aether black holes have higher oscillation frequencies than Schwarzschild black holes.

Damping rates of Einstein-Aether black holes are larger than those in Einstein's theory.

The method is versatile for various numerical black hole solutions.

Abstract

We develop a new method for calculation of quasi-normal modes of black holes, when the effective potential, which governs black hole perturbations, is known only numerically in some region near the black hole. This method can be applied to perturbations of a wide class of numerical black hole solutions. We apply it to the black holes in the Einstein-Aether theory, a theory where general relativity is coupled to a unit time-like vector field, in order to observe local Lorentz symmetry violation. We found that in the non-reduced Einstein-Aether theory, real oscillation frequency and damping rate of quasi-normal modes are larger than those of Schwarzschild black holes in the Einstein theory.