An analysis of the phase space of Horava-Lifshitz cosmologies

TL;DR

This paper systematically analyzes the phase space of Horava-Lifshitz cosmologies using dynamical systems, revealing how detailed balance conditions influence universe evolution and the potential for models to match current observations.

Contribution

It provides a comprehensive phase space analysis of Horava-Lifshitz cosmologies, highlighting the impact of detailed balance on cosmological attractors and universe evolution.

Findings

Detailed balance leads to oscillatory attractors and bouncing universe scenarios.

Breaking detailed balance allows models to transition between Friedmann and dark energy eras.

Cosmologies without detailed balance can better fit current universe observations.

Abstract

Using the dynamical system approach, properties of cosmological models based on the Horava-Lifshitz gravity are systematically studied. In particular, the cosmological phase space of the Horava-Lifshitz model is characterized. The analysis allows to compare some key physical consequences of the imposition (or not) of detailed balance. A result of the investigation is that in the detailed balance case one of the attractors in the theory corresponds to an oscillatory behavior. Such oscillations can be associated to a bouncing universe, as previously described by Brandenberger, and will prevent a possible evolution towards a de Sitter universe. Other results obtained show that the cosmological models generated by Horava-Lifshitz gravity without the detailed balance assumption have indeed the potential to describe the transition between the Friedmann and the dark energy eras. The whole analysis leads to the plausible conclusion that a cosmology compatible with the present observations of the universe can be achieved only if the detailed balance condition is broken.