Cosmological constraints on $f(Q)$ gravity models in the non-coincident formalism

TL;DR

This paper explores new $f(Q)$ gravity models in a non-coincident formalism, deriving unique cosmological equations, proposing a novel Hubble parameter parameterization, and constraining models with observational data and stability analyses.

Contribution

It introduces a new $f(Q)$ gravity dynamics with a non-vanishing affine connection and develops a parameterization of the Hubble function compatible with observations.

Findings

Constraints on $f(Q)$ model parameters from observational data.

Evaluation of model reliability using AIC and BIC criteria.

Assessment of thermodynamical stability of the models.

Abstract

The article investigates cosmological applications of $f(Q)$ theories in a non-coincident formalism. We explore a new $f(Q)$ theory dynamics utilizing a non-vanishing affine connection involving a non-constant function $\gamma(t)=-a^{-1}\dot{H}$, resulting in Friedmann equations that are entirely distinct from those of $f(T)$ theory. In addition, we propose a new parameterization of the Hubble function that can consistently depicts the present deceleration parameter value, transition redshift, and the late time de-Sitter limit. We evaluate the predictions of the assumed Hubble function by imposing constraints on the free parameters utilizing Bayesian statistical analysis to estimate the posterior probability by employing the CC, Pantheon+SH0ES, and the BAO samples. Moreover, we conduct the AIC and BIC statistical evaluations to determine the reliability of MCMC analysis. Further, we consider some well-known corrections to the STEGR case such as an exponentital $f(Q)$ correction, logarithmic $f(Q)$ correction, and a power-law $f(Q)$ correction and then we find the constraints on the parameters of these models via energy conditions. Finally, to test the physical plausibility of the assumed $f(Q)$ models we conduct the thermodynamical stability analysis via the sound speed parameter.