Cosmic observation of a model in the horizon of $ f(Q, C) $-gravity

TL;DR

This paper develops a cosmological model within $f(Q,C)$ gravity, constrains it with observational data, and finds it describes an expanding universe transitioning from deceleration to acceleration, resembling quintessence dark energy and converging to $\\Lambda$CDM.

Contribution

The work introduces a novel $f(Q,C)$ gravity model incorporating boundary terms and constrains it with multiple datasets, showing its viability in describing cosmic acceleration.

Findings

Model transitions from deceleration to acceleration.

Model behaves as quintessence dark energy.

Converges to $\\Lambda$CDM at late times.

Abstract

In this work, we developed a cosmological model in $ f(Q, C) $ gravity within the framework of symmetric teleparallel geometry. In addition to the non-metricity scalar $Q $, our formulation includes the boundary term $ C $, which accounts for its deviation from the standard Levi-Civita Ricci scalar $ R^* $ in the Lagrangian. We derived the field equations for the metric and affine connection, employed them within a cosmological setting, and a vanishing affine connection to derive modified Friedmann equations. We used the latest observational dataset OHD in the redshift range $ z \in [0, 2.36]$, Pantheon + SH0ES in the redshift range $ z \in (0.01, 2.26)$, BAO, and the joint datasets OHD + Pantheon + SH0ES and OHD + Pantheon + SH0ES + BAO to constrain the parameters of our model by employing Markov Chain Monte Carlo (MCMC) method to minimize the $\chi^2$ term. Using the constrained free model parameters, we carefully analyzed the behavior of different physical parameters and verified that the model transits from deceleration to acceleration. Finally, we observed that the model demonstrates an expanding quintessence dark energy model and converges to the $ \Lambda $CDM in later times.