Abstract:
We conduct a Bayesian analysis of recent observational datasets, specifically the Cosmic Chronometers (CC) dataset and
Pantheon samples, to investigate the evolution of the EoS parameter in dark energy models. Our study focused on the effective EoS
parameter, which is described by the parametric form ωef f − 1
1+m(1+z)n , where m and n are model parameters. This parametric
form is applicable within the framework of f (R, Lm) gravity, where R represents the Ricci scalar and Lm is the matter Lagrangian.
Here, we examine a non-linear f (R, Lm) model characterized by the functional form f (R, Lm) R
2 + Lα
m, where α is the free
parameter of the model. We examine the evolution of several cosmological parameters, including the effective EoS parameter ωef f ,
the deceleration parameter q, the density parameter ρ, the pressure p, and the statefinder parameters. Our analysis revealed that
the constrained current value of the effective EoS parameter, ω0
ef f −0.68 ± 0.06 for both the CC and Pantheon datasets, points
towards a quintessence phase. Moreover, at redshift z 0, the deceleration parameter, q0 −0.61+0.01 −0.01, indicates that the present
Universe is undergoing accelerated expansion.
