Evolving Horava Cosmological Horizons

TL;DR

This paper investigates the properties and formation of cosmological and black hole horizons in Horava gravity, using null congruences to analyze trapping horizons in various cosmological models.

Contribution

It introduces a method to analyze trapping horizons in Horava universes and explores conditions for horizon formation in expanding and contracting cosmologies.

Findings

Identification of conditions for trapped and anti-trapped surfaces in Horava cosmologies.

Analysis of horizon properties in standard FLRW models within Horava gravity.

Discussion of horizon formation in negative time and the finite past.

Abstract

Several sets of radially propagating null congruence generators are exploited in order to form 3-dimensional marginally trapped surfaces, referred to as black hole and cosmological apparent horizons in a Horava universe. Based on this method, we deal with the characteristics of the 2-dimensional space-like spheres of symmetry and the peculiarities of having trapping horizons. Moreover, we apply this method in standard expanding and contracting FLRW cosmological models of a Horava universe to investigate the conditions under which the extra parameters of the theory may lead to trapped/anti-trapped surfaces both in the future and in the past. We also include the cases of negative time, referred to as the finite past, and discuss the formation of anti-trapped surfaces inside the cosmological apparent horizons.