Observational Constraints on Noncoincident $f(Q)$-Gravity with Matter-Gravity Coupling

TL;DR

This paper explores a modified gravity model with matter coupling as a candidate for explaining late-time cosmic acceleration, using observational data to constrain its parameters and compare it with the standard $\\Lambda$CDM model.

Contribution

It introduces a noncoincident $f(Q)$-gravity model with matter coupling and provides observational constraints, showing its statistical viability compared to $\\Lambda$CDM.

Findings

Best-fit power-law index $n \simeq 2$ from data.

$f(Q)$-gravity models have likelihoods comparable to $\\Lambda$CDM.

Model constraints are consistent across different observational datasets.

Abstract

We investigate $f\left( Q\right) $-gravity with a matter-gravity coupling as a geometric dark energy candidate for the description of the late-time cosmic acceleration within a spatially flat Friedmann--Lema\^{\i}tre-Robertson-Walker geometry. We select a noncoincident connection that naturally follows from the general framework of cosmological models with nonzero spatial curvature. We present observational constraints for the simplest $f\left( Q\right) =f_{0}Q^{n}$ model using data from Supernovae, Baryon Acoustic Oscillations and Cosmic Chronometers. For different data combinations we found consistent constraints, with a best-fit value for the power-law index $n\simeq2$. A comparison with the $\Lambda$CDM model shows that the $f\left( Q\right) $-gravity leads to larger values for the likelihood, while Akaike's Information Criterion suggests statistical equivalence between the two models for most data combinations.