Aspects of Horava-Lifshitz cosmology

TL;DR

This paper reviews Horava-Lifshitz cosmology, deriving equations, constraining parameters with data, analyzing late-time solutions, and discussing stability issues and potential for describing dark energy phenomena.

Contribution

It provides a comprehensive overview of Horava-Lifshitz cosmology, including phase-space analysis and stability considerations, highlighting the need for theory modifications.

Findings

Stable late-time solutions including eternal, bouncing, and cyclic expansion.

Effective dark energy can mimic phantom behavior without phantom fields.

Basic version suffers from instabilities requiring modifications.

Abstract

We review some general aspects of Horava-Lifshitz cosmology. Formulating it in its basic version, we extract the cosmological equations and we use observational data in order to constrain the parameters of the theory. Through a phase-space analysis we extract the late-time stable solutions, and we show that eternal expansion, and bouncing and cyclic behavior can arise naturally. Concerning the effective dark energy sector we show that it can describe the phantom phase without the use of a phantom field. However, performing a detailed perturbation analysis, we see that Horava-Lifshitz gravity in its basic version suffers from instabilities. Therefore, suitable generalizations are required in order for this novel theory to be a candidate for the description of nature.