Holographic energy density on Ho\v{r}ava-Lifshitz cosmology

TL;DR

This paper investigates holographic energy density within Hořava-Lifshitz cosmology, analyzing cosmic evolution, energy non-conservation, and thermal properties, revealing complex behaviors and the necessity of a ghost scalar graviton for observational consistency.

Contribution

It introduces a holographic Ricci-like cut-off in Hořava-Lifshitz cosmology and explores its implications on cosmic evolution, energy exchange, and the nature of dark energy.

Findings

Power-law solution for scale factor during early stage

Late and early phantom schemes are theoretically possible but not feasible

No thermal equilibrium between bulk and boundary in this framework

Abstract

In Ho\v{r}ava-Lifshitz cosmology we use the holographic Ricci-like cut-off for the energy density proposed by L. N. Granda and A. Oliveros and under this framework we study, through the cosmic evolution at late times, the sign change in the amount of non-conservation energy ($Q$) present in this cosmology. We revise the early stage (curvature-dependent) of this cosmology, where a term reminiscent of stiff matter is the dominant, and in this stage we find a power-law solution for the cosmic scale factor although $\omega =-1$. Late and early phantom schemes are obtained without requiring $\omega <-1$. Nevertheless, these schemes are not feasible according to what is shown in this paper. We also show that $ \omega =-1$ alone does not imply a de Sitter phase in the present cosmology. Thermal aspects are revised by considering the energy interchange between the bulk and the spacetime boundary and we conclude that there is no thermal equilibrium between them. Finally, a ghost scalar graviton (extra degree of freedom in HL gravity) is required by the observational data.