Reconstructing the interaction term between dark matter and dark energy

TL;DR

This paper employs a Chebyshev polynomial-based reconstruction method to analyze the interaction between dark matter and dark energy, revealing a potential energy transfer from dark matter to dark energy that challenges the viability of such models.

Contribution

It introduces a novel parametric reconstruction approach using Chebyshev polynomials to model dark sector interactions in a flat FRW universe.

Findings

Best-fit scenario indicates energy transfer from DM to DE

Reconstruction suggests interaction worsens the cosmic coincidence problem

Method provides estimates for interaction coefficients and DE equation of state

Abstract

We apply a parametric reconstruction method to a homogeneous, isotropic and spatially flat Friedmann-Robertson-Walker (FRW) cosmological model filled of a fluid of dark energy (DE) with constant equation of state parameter interacting with dark matter (DM). The reconstruction method is based on expansions of the general interaction term and the relevant cosmological variables in terms of Chebyshev polynomials which form a complete set orthonormal functions. This interaction term describes an exchange of energy flow between the DE and DM within dark sector. To show how the method works we do the reconstruction of the interaction function expanding it in terms of only the first three Chebyshev polynomials and obtain the best estimation for the coefficients of the expansion as well as for the DE equation of the state constant parameter w using the type Ia Supernova SCP Union data set (307 SNe-Ia). The preliminary reconstruction shows that in the best scenario there is an energy transfer from DM to DE which worsen the problem of the cosmic coincidence in comparison with the LCDM model. We conclude that this fact is an indication of a serious drawback for the existence of such interaction between dark components.