Cosmological constrains on minimally and non-minimally coupled scalar field models

TL;DR

This paper investigates minimally and non-minimally coupled scalar field models as alternatives to dark energy, comparing their cosmological constraints with data, and finds that the standard DM model remains favored unless local Hubble constant measurements are included.

Contribution

It provides updated observational constraints on scalar field dark energy models and explores their viability relative to DM, including the coupling parameter  and tension reduction.

Findings

DM is strongly favored without local H0 data.

Scalar field models reduce the  tension.

Coupling constant  constrained near solar system limits.

Abstract

We study the minimally and non-minimally coupled scalar field models as possible alternatives for dark energy, the mysterious energy component that is driving the accelerated expansion of the universe. After discussing the dynamics at both the background and perturbation level, we confront the two models with the latest cosmological data. After obtaining updated constraints on their parameters we perform model selection using the basic information criteria. We found that the $\Lambda$CDM model is strongly favored when the local determination of the Hubble constant is not considered and that this statement is weakened once local $H_0$ is included in the analysis. We calculate the parameter combination $S_8=\sigma_8\sqrt{\Omega_{m}/0.3}$ and show the decrement of the tension with respect to the Planck results in the case of minimally and non-minimally coupled scalar field models. Finally, for the coupling constant between DE and gravity, we obtain the constraint $\xi\simeq -0.06^{+0.19}_{-0.19}$, approaching the one from solar system tests $|\xi| \lesssim 10^{-2}$ and comparable to the conformal value $\xi=1/6$ at $1\sigma$ uncertainty.