Coupled Quintessence scalar field model in light of observational datasets

TL;DR

This paper analyzes a coupled quintessence dark energy model with a time-varying interaction, using diverse observational datasets, revealing potential deviations from a cosmological constant and a preference for the coupled model over ΛCDM.

Contribution

It provides a comprehensive observational analysis of a coupled quintessence model with a time-varying interaction, highlighting its compatibility with current data and potential advantages over ΛCDM.

Findings

Dark energy may differ from a cosmological constant at early times.

Small dark energy-dark matter interaction is not ruled out at late times.

Coupled quintessence model is preferred over ΛCDM based on AIC and BIC criteria.

Abstract

We do a detailed analysis of a well-theoretically motivated interacting dark energy scalar field model with a time-varying interaction term. Using current cosmological datasets from CMB, BAO, Type Ia Supernova, $H(z)$ measurements from cosmic chronometers, angular diameter measurements from Megamasers, growth measurements, and local SH0ES measurements, we found that dark energy component may act differently than a cosmological constant at early times. The observational data also does not disfavor a small interaction between dark energy and dark matter at late times. When using all these datasets in combination, our value of $H_0$ agrees well with SH0ES results but in 2.5$\sigma$ tension with Planck results. We also did AIC and BIC analysis, and we found that the cosmological data prefer coupled quintessence model over $\Lambda$CDM, although the chi-square per number of degrees of freedom test prefers the latter.