A constrained cosmological model in f (R, Lm) gravity

In this article, we study the expanding nature of the universe in the context of f(R, Lm) gravity theory, here R represents the Ricci scalar and Lm is the matter Lagrangian density. With a specific form of f(R, Lm), we obtain the field equations for flat FLRW metric. We parametrize the deceleration parameter in terms of the Hubble parameter and from here we find four free parameters, which are constraints and estimated by using H(z), Pantheon, and their joint data sets. Further, we investigate the evolution of the deceleration parameter which depicts a transition from the deceleration to acceleration phases of the universe. The evolutionary behaviour of energy density, pressure, and EoS parameter shows that the present model is an accelerated quintessence dark energy model. To compare our model with the ACDM model we use some of the diagnostic techniques. Thus, we find that our model in f (R, Lm) gravity supports the recent standard observational studies and delineates the late-time cosmic acceleration.