Interacting holographic dark energy models: A general approach

TL;DR

This paper explores holographic dark energy models with a general density form, analyzing their dynamics, interactions, and conditions to avoid the phantom divide crossing, providing insights into dark energy behavior and the coincidence problem.

Contribution

It introduces a general approach to interacting holographic dark energy models, including special cases like Ricci dark energy, and studies their dynamics and observational implications.

Findings

Crossing of phantom divide can be avoided for certain parameter choices.

Interaction term Q∝Hρ_m helps resolve the coincidence problem.

A specific parameter set leads to a Λ-like varying dark energy model.

Abstract

Dark energy models inspired by the cosmological holographic principle are studied in homogeneous isotropic spacetime with a general choice for the dark energy density $\rho_d=3(\alpha H^2+\beta\dot{H})$. Special choices of the parameters enable us to obtain three different holographic models, including the holographic Ricci dark energy(RDE) model. Effect of interaction between dark matter and dark energy on the dynamics of those models are investigated for different popular forms of interaction. It is found that crossing of phantom divide can be avoided in RDE models for $\beta>0.5$ irrespective of the presence of interaction. A choice of $\alpha=1$ and $\beta=2/3$ leads to a varying $\Lambda$-like model introducing an IR cutoff length $\Lambda^{-1/2}$. It is concluded that among the popular choices an interaction of the form $Q\propto H\rho_m$ suits the best in avoiding the coincidence problem in this model.