Scalar perturbations in cosmological models with dark energy - dark matter interaction

TL;DR

This paper studies scalar perturbations in cosmological models where dark energy and dark matter interact, using discrete cosmology methods to derive constraints and compare with observations.

Contribution

It introduces a new interacting dark sector model with evolving coefficients and applies discrete cosmology to derive theoretical constraints.

Findings

Derived strong theoretical constraints on model parameters

Compared model predictions with observational data

Identified conditions for stability of perturbations

Abstract

Scalar cosmological perturbations are investigated in the framework of a model with interacting dark energy and dark matter. In addition to these constituents, the inhomogeneous Universe is supposed to be filled with the standard noninteracting constituents corresponding to the conventional $\Lambda$CDM model. The interaction term is chosen in the form of a linear combination of dark sector energy densities with evolving coefficients. The methods of discrete cosmology are applied, and strong theoretical constraints on the parameters of the model are derived. A brief comparison with observational data is performed.