Interacting Quintessence and Growth of Structure

TL;DR

This paper investigates how direct interactions between dark energy and dark matter in the interacting quintessence model affect the growth of cosmic structures and power spectra, revealing scale-dependent deviations from standard cosmology.

Contribution

It introduces analysis of the interacting quintessence model with a linear potential, quantifying deviations in power spectra due to dark energy-dark matter interaction.

Findings

Deviation in power spectrum increases with interaction strength.

Large scale deviations are mainly due to dark energy perturbations.

Small scale deviations are primarily caused by background evolution.

Abstract

In standard cosmologies, dark energy interacts only gravitationally with dark matter. An extension to this picture is interacting quintessence (IQ) model, where scalar field coupled directly to cold dark matter. The percentage deviation is studied in IQ model wrt $\Lambda$CDM for varied values of interacting parameter W. We investigated the effect of interaction on matter, Kaiser and galaxy power spectrums. Deviation in power spectrum increases with interaction on both large and small scales. On small scale, variation is comparatively smaller than on large scale. On large scale, it is due to dark energy perturbation while it is background evolution that causes a difference on small scale. These variations decrease with increase in redshift. Herein thawing class of model with linear potential is studied.