Late-time cosmology with phantom dark-energy in f(Q) gravity
Andreas Lymperis
Abstract
Abstract Motivated by the exciting features and a recent proposed general form of the function of non-metricity scalar Q, we investigate the cosmological implications in f ( Q ) gravity, through the resulting effective dark energy sector, extracting analytical expressions for the dark energy density, equation-of-state and the deceleration parameters. We show that even in the absence of a cosmological constant, the universe exhibits the usual thermal history, with the sequence of matter and dark energy eras, and the dark-energy equation-of-state parameter always lie in the phantom regime. Additionally, calculating the age of the universe, through the extracted analytical equations of the scenario at hand, we show that the result coincide with the value corresponding to ΛCDM scenario within 1σ. Moreover, we show the excellent agreement of the scenario at hand with Supernovae type Ia observational data. Lastly, comparing the cosmological behavior in the case of the absence of an explicit cosmological constant, with the one of the presence of a cosmological constant we show that f ( Q ) gravity can mimic the cosmological constant in a very efficient way, providing very similar behavior, revealing the advantages and capabilitites of the scenario at hand.