Late-time cosmology with phantom dark-energy in $f(Q)$ gravity

TL;DR

This paper explores $f(Q)$ gravity as an alternative to dark energy, showing it can replicate the universe's thermal history, match observational data, and mimic a cosmological constant without explicitly including one.

Contribution

It provides analytical expressions for dark energy parameters in $f(Q)$ gravity and demonstrates its ability to replicate $ ext{Lambda}$CDM behavior and fit supernova data.

Findings

Dark energy equation-of-state always in phantom regime

Universe's age matches $ ext{Lambda}$CDM within 1$\sigma$

Excellent fit to Supernovae Ia data

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 parameter 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 $\Lambda$CDM scenario within 1$\sigma$. 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.