Omnipotent dark energy: A phenomenological answer to the Hubble tension

Understand

This paper introduces the class of omnipotent dark energy (DE) models characterized by nonmonotonic energy densities that are capable of attaining negative values with corresponding equation of state parameters featuring phantom divide line (PDL) crossings and singularities.

• These nontrivial features are phenomenologically motivated by findings of previous studies that reconstruct cosmological functions from observations, and the success of extensions of $\Lambda$CDM, whose actual or effective DE density is omnipotent, in alleviating the observational discordance within $\Lambda$CDM.
• As an example, we focus on one embodiment of omnipotent DE, viz., the DE parametrization introduced in Di Valentino et al.
• [Dark energy with phantom crossing and the H0 tension, Entropy 23, 404 (2021)] (DMS20).