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arXiv · 1911.00209

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

Zahra Davari·Valerio Marra·Mohammad Malekjani
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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.

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Zahra Davari, Valerio Marra, Mohammad Malekjani. 2019-11-01. Cosmological constrains on minimally and non-minimally coupled scalar field models. https://doi.org/10.1093/mnras%2Fstz3096

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