Phase portrait of a matter bounce in Horava-Lifshitz cosmology

The occurrence of a bounce in the FRW cosmology requires modifications of general relativity. An example of such a modification is the recently proposed Horava-Lifshitz theory of gravity, which includes a 'dark radiation' term with a negative coefficient in the analog of the Friedmann equation. This paper describes a phase space analysis of models of this sort with the aim of determining to what extent bouncing solutions can occur. It is found that they are possible, but not generic in models under consideration. Apart from previously known bouncing solutions, some new ones are also described. Other interesting solutions found include ones that describe a novel sort of quasi stationary, oscillating universe.