English

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

General Relativity and Quantum Cosmology 2019-12-03 v1 Cosmology and Nongalactic Astrophysics High Energy Physics - Theory

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 Λ\LambdaCDM model is strongly favored when the local determination of the Hubble constant is not considered and that this statement is weakened once local H0H_0 is included in the analysis. We calculate the parameter combination S8=σ8Ωm/0.3S_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 ξ0.060.19+0.19\xi\simeq -0.06^{+0.19}_{-0.19}, approaching the one from solar system tests ξ102|\xi| \lesssim 10^{-2} and comparable to the conformal value ξ=1/6\xi=1/6 at 1σ1\sigma uncertainty.

Keywords

Cite

@article{arxiv.1911.00209,
  title  = {Cosmological constrains on minimally and non-minimally coupled scalar field models},
  author = {Zahra Davari and Valerio Marra and Mohammad Malekjani},
  journal= {arXiv preprint arXiv:1911.00209},
  year   = {2019}
}

Comments

15 pages, 11 figures and 4 tables. Accepted in MNRAS