Probing the imprints of generalized interacting dark energy on the growth of perturbations

TL;DR

This paper investigates how generalized interactions between dark energy and dark matter influence cosmic structures and signatures, revealing unique oscillatory features in matter growth rates due to disformal coupling.

Contribution

It introduces and analyzes the effects of disformal and conformal couplings in dark energy-dark matter interactions on cosmological observables.

Findings

Disformal coupling causes time-dependent damped oscillations in matter growth.

Distinct signatures appear in the CMB power spectrum and growth rate functions.

Combined couplings offer a richer phenomenology for dark sector interactions.

Abstract

We extensively study the evolution and distinct signatures of cosmological models, in which dark energy interacts directly with dark matter. We first focus on the imprints of these coupled models on the cosmic microwave background temperature power spectrum, in which we discuss the multipole peak separation together with the integrated Sachs-Wolfe effect. We also address the growth of matter perturbations, and disentangle the interacting dark energy models using the expansion history together with the growth history. We find that a disformal coupling between dark matter and dark energy induces intermediate-scales and time-dependent damped oscillatory features in the matter growth rate function, a unique characteristic of this coupling. Apart from the disformal coupling, we also consider conformally coupled models, together with models which simultaneously make use of both couplings.