\(\boldsymbol{f(Q)}\) Gravity and Affine EoS: Compatibility and Observational Constraints

Abstract

We study the cosmological implications of a barotropic fluid satisfying an affine equation of state (EoS) in general relativity (GR) and \(f(Q)\) gravity. We describe the impact of the affine EoS on the cosmic evolution in the model and derive observational constraints on the model parameters. The models of GR and \(f(Q)\) gravity may provide a scenario in which the universe transits from decelerated into accelerated expansion. The model parameters are constrained by Bayesian analysis based on the \(\chi^{2}\) minimization technique with the observational data of the Cosmic chronometer and Type Ia Supernovae. The affine EoS model in GR possesses a quintessence kind of dark energy, while it has a phantom type of dark energy in \(f(Q)\) gravity. The present-day values of the cosmological parameters along with the current age of the universe are compatible with observations. We also probe the possibility of setting up the solution of the GR model into \(f(Q)\) gravity.