Towards constraining of the Horava-Lifshitz gravities

TL;DR

This paper investigates observable differences in black hole properties, such as gravitational lensing and quasinormal modes, within Horava-Lifshitz gravity, aiming to test deviations from General Relativity at astrophysical scales.

Contribution

It analyzes black hole signatures in Horava-Lifshitz gravity with Minkowski vacuum, highlighting potential observable deviations from GR in lensing and quasinormal modes.

Findings

Bending angle is smaller than in GR.

Black hole quasinormal modes are longer lived.

Oscillation frequencies are higher than in GR.

Abstract

Recently a renormalizable model of gravity has been proposed, which might be a UV completion of General Relativity (GR) or its infra-red modification, probably with a strongly coupled scalar mode. Although the generic vacuum of the theory is anti-de Sitter one, particular limits of the theory allow for the Minkowski vacuum. In this limit (though without consideration of the strongly coupled scalar field) post-Newtonian coefficients of spherically symmetric solutions coincide with those of the General Relativity. Thus the deviations from the convenient GR should be tested beyond the post-Newtonian corrections, that is for a system with strong gravity at astrophysical scales. In this letter we consider potentially observable properties of black holes in the deformed Horava-Lifshitz gravity with Minkowski vacuum: the gravitational lensing and quasinormal modes. We have showed that the bending angle is seemingly smaller in the considered Horava-Lifshitz gravity than in GR. The quasinormal modes of black holes are longer lived and have larger real oscillation frequency in the Horava-Lifshitz gravity than in GR. These corrections should be observable in the near future experiments on lensing and by gravitational antennas, helping to constrain parameters of the Horava-Lifshitz gravity or to discard it.