Cosmology with Ricci-type dark energy

Abstract

We consider the dynamics of a cosmological substratum of pressureless matter and holographic dark energy with a cutoff length proportional to the Ricci scale. Stability requirements for the matter perturbations are shown to single out a model with a fixed relation between the present matter fraction ${\Omega }_{m0}$ and the present value ${\omega }_0$ of the equation-of-state parameter of the dark energy. This model has the same number of free parameters as the $\Lambda$CDM model but it has no $\Lambda$CDM limit. We discuss the consistency between background observations and the mentioned stability-guaranteeing parameter combination.

arXiv comment6 pages, 3 figures, submitted to the Proceedings of the CosmoSurII conference, Valparaíso, Chile, 27 - 31 May 2013