Density perturbation in an interacting holographic dark energy model

TL;DR

This study investigates the evolution of density perturbations in a cosmological model with interacting holographic dark energy and cold dark matter, revealing that both components can cluster and exhibit growth, with implications for cosmic acceleration.

Contribution

It introduces a numerical analysis of density contrasts in an interacting holographic dark energy model with the future event horizon as IR cut-off, highlighting clustering behavior.

Findings

Both dark matter and holographic dark energy show growing perturbations.

HDE perturbations peak in the recent past and decay currently.

The IR cut-off as the event horizon does not naturally lead to accelerated expansion.

Abstract

The present work deals with the evolution of the density contrasts for a cosmological model where along with the standard cold dark matter (CDM), the present Universe also contains holographic dark energy (HDE). The characteristic infra-red (IR) cut-off is taken as the future event horizon. The HDE is allowed to interact with the CDM. The equations for the density contrasts are integrated numerically. It is found that irrespective of the presence of an interaction, the matter perturbation has growing modes. The HDE is also found to have growth of perturbation, so very much like the CDM, thus can also cluster. The interesting point to note is that the density contrast corresponding to HDE has a peak at recent past and is decaying at the present epoch. Another feature is that IR cut-off as the event horizon does not naturally produce accelerated expansion of the Universe in the presence of an interaction.