Bumpy black holes from spontaneous Lorentz violation

TL;DR

This paper explores how Lorentz violation in massive gravity theories leads to non-universal black holes with hairs that could reveal insights into quantum gravity and be detectable via future gravitational wave observations.

Contribution

It introduces the concept of black hole hairs arising from Lorentz violation in massive gravity, challenging the universality of black hole solutions.

Findings

Black holes can have observable hairs in Lorentz violating theories.

Hairs probe the black hole interior, offering a window into quantum gravity.

Hairs are likely suppressed for super-massive black holes due to graviton mass constraints.

Abstract

We consider black holes in Lorentz violating theories of massive gravity. We argue that in these theories black hole solutions are no longer universal and exhibit a large number of hairs. If they exist, these hairs probe the singularity inside the black hole providing a window into quantum gravity. The existence of these hairs can be tested by future gravitational wave observatories. We generically expect that the effects we discuss will be larger for the more massive black holes. In the simplest models the strength of the hairs is controlled by the same parameter that sets the mass of the graviton (tensor modes). Then the upper limit on this mass coming from the inferred gravitational radiation emitted by binary pulsars implies that hairs are likely to be suppressed for almost the entire mass range of the super-massive black holes in the centers of galaxies.