Dark Energy: A Unifying View

TL;DR

This paper presents a unified holographic dark energy framework that encompasses various models like $\\Lambda$CDM and Chaplygin gas, highlighting the role of dark matter-dark energy interaction and non-adiabatic pressure perturbations.

Contribution

It introduces a unifying holographic dark energy model incorporating dark matter-dark energy interaction, emphasizing differences at the perturbative level.

Findings

Interaction strength acts as a cosmological constant.

Models exhibit non-adiabatic pressure perturbations.

Differences emerge at the perturbation level.

Abstract

Different models of the cosmic substratum which pretend to describe the present stage of accelerated expansion of the Universe like the $\Lambda$CDM model or a Chaplygin gas, can be seen as special realizations of a holographic dark energy cosmology if the option of an interaction between pressurless dark matter and dark energy is taken seriously. The corresponding interaction strength parameter plays the role of a cosmological constant. Differences occur at the perturbative level. In particular, the pressure perturbations are intrinsically non-adiabatic.