Dynamical dark energy: Scalar fields and running vacuum

Abstract

Recent analyses in the literature suggest that the concordance [Formula: see text]CDM model with rigid cosmological term, [Formula: see text] may not be the best description of the cosmic acceleration. The class of “running vacuum models”, in which [Formula: see text] evolves with the Hubble rate, has been shown to fit the string of SNIa + BAO + H(z) + LSS + CMB data significantly better than the [Formula: see text]CDM. Here, we provide further evidence on the time-evolving nature of the dark energy (DE) by fitting the same cosmological data in terms of scalar fields. As a representative model, we use the original Peebles and Ratra potential, [Formula: see text]. We find clear signs of dynamical DE at [Formula: see text] c.l., thus reconfirming through a nontrivial scalar field approach the strong hints formerly found with other models and parametrizations.