Holographic dark energy with varying gravitational constant

Mubasher Jamil,Emmanuel N Saridakis,M.R Setare

doi:10.1016/j.physletb.2009.07.048

Abstract

We investigate the holographic dark energy scenario with a varying gravitational constant, in flat and non-flat background geometry. We extract the exact differential equations determining the evolution of the dark energy density-parameter, which include G-variation correction terms. Performing a low-redshift expansion of the dark energy equation of state, we provide the involved parameters as functions of the current density parameters, of the holographic dark energy constant and of the G-variation.

Highlights

Recent cosmological observations obtained by SNe Ia [1], WMAP [2], SDSS [3] and X-ray [4] indicate that the universe experiences an accelerated expansion
Going beyond the above effective description requires a deeper understanding of the underlying theory of quantum gravity [9] unknown at present, physicists can still make some attempts to probe the nature of dark energy according to some basic quantum gravitational principles
Determining an appropriate quantity L to serve as an IR cut-off, imposing the constraint that the total vacuum energy in the corresponding maximum volume must not be greater than the mass of a black hole of the same size, and saturating the inequality, one identifies the acquired

Summary

INTRODUCTION

Recent cosmological observations obtained by SNe Ia [1], WMAP [2], SDSS [3] and X-ray [4] indicate that the universe experiences an accelerated expansion. Going beyond the above effective description requires a deeper understanding of the underlying theory of quantum gravity [9] unknown at present, physicists can still make some attempts to probe the nature of dark energy according to some basic quantum gravitational principles. In this work we are interested in investigating the holographic dark energy paradigm allowing for a varying gravitational constant, and extracting the corresponding corrections to the dark energy equation-ofstate parameter. In order to remain general and explore the pure varying-G effects in a model-independent way, we do not use explicitly any additional, geometrical or quintessence-like, scalar field, considering just the Hilbert-Einstein action in an affective level, as it arises from gravitational holography [42, 43].

Flat FRW geometry

Non-flat FRW geometry

COSMOLOGICAL IMPLICATIONS

CONCLUSIONS