# Observational constraints of $f(Q)$ gravity

## TL;DR

This paper investigates $f(Q)$ gravity, an extension of symmetric teleparallel gravity, by analyzing various polynomial models against multiple cosmological observations to assess their viability as alternatives to $\\Lambda$CDM for explaining late-time cosmic acceleration.

## Contribution

It introduces a redshift-based reformulation of $f(Q)$ gravity models and tests their observational consistency using diverse cosmological data sets.

## Key findings

- Some $f(Q)$ models fit observational data well
- Deviations from $\\Lambda$CDM are possible within this framework
- The approach offers a new perspective on alternative gravity models

## Abstract

In this work, we consider an extension of symmetric teleparallel gravity, namely, $f(Q)$ gravity, where the fundamental block to describe spacetime is the nonmetricity, $Q$. Within this formulation of gravitation, we perform an observational analysis of several modified $f(Q)$ models using the redshift approach, where the $f(Q)$ Lagrangian is reformulated as an explicit function of the redshift, $f(z)$. Various different polynomial parameterizations of $f(z)$ are proposed, including new terms which would allow for deviations from the $\Lambda$CDM model. Given a variety of observational probes, such as the expansion rate data from early-type galaxies, Type Ia Supernovae, Quasars, Gamma Ray Bursts, Baryon Acoustic Oscillations data and Cosmic Microwave Background distance priors, we have checked the validity of these models at the background level in order to verify if this new formalism provides us with plausible alternative models to explain the late time acceleration of the universe. Indeed, this novel approach provides a different perspective on the formulation of observationally reliable alternative models of gravity.