Dynamics of Interacting Quintessence Models: Observational Constraints

TL;DR

This paper examines the dynamical evolution of interacting quintessence models, testing their ability to reproduce cosmic history and address the coincidence problem, using observational data across multiple redshift epochs.

Contribution

It analyzes a specific interacting quintessence model's evolution and observational constraints, assessing its viability to solve the coincidence problem.

Findings

The model reproduces radiation, dark matter, and dark energy eras.

Observational data heavily constrain the model.

The coupling does not clearly solve the coincidence problem.

Abstract

Interacting quintessence models have been proposed to explain or, at least, alleviate the coincidence problem of late cosmic acceleration. In this paper we are concerned with two aspects of these kind of models: (i) the dynamical evolution of the model of Chimento et al. [L.P. Chimento, A.S. Jakubi, D. Pavon, and W. Zimdahl, Phys. Rev. D 67, 083513 (2003).], i.e., whether its cosmological evolution gives rise to a right sequence of radiation, dark matter and dark energy dominated eras, and (ii) whether the dark matter dark energy ratio asymptotically evolves towards a non-zero constant. After showing that the model correctly reproduces these eras, we correlate three data sets that constrain the interaction at three redshift epochs: $z\le 10^{4}$, $z=10^{3}$, and $z=1$. We discuss the model selection and argue that even if the model under consideration fulfills both requirements, it is heavily constrained by observation. The prospects that the coincidence problem can be explained by the coupling of dark matter to dark energy are not clearly favored by the data.