FLRW Cosmological Models with Dynamic Cosmological Term in Modified Gravity

Abstract

Although the standard lambda cold dark matter cosmological model is quite successful in describing the universe, there are still several issues that are still not resolved. Some of these are the cosmological constant problem, certain anomalies in the cosmic microwave background radiation and whether general relativity is valid on large scales. Therefore, it is interesting to examine modified theories in an attempt to solve these problems, and to examine the entire range of possibilities that are allowed. In this work, we examine one of these modified theories, viz., f(R,T) gravity. We study the homogeneous and isotropic models in this theory, which have some pleasing features, such as no initial singularity, a dynamic cosmological term, and a transition from early deceleration to late-time acceleration as intimated by observations. The physical parameters of the model, as well as the energy conditions, are discussed and a viable cosmological model can be constructed.

Hyperbolic Scenario of Accelerating Universe in Modified Gravity

“…where in H denotes the Hubble parameter and α and β denote negative and positive constants.The authors of [74][75][76][77] discuss the underlying reasoning for adopting such an assumption. Scale factor a(t) could be derived by integrating Equation ( 23) and utilizing the definition of deceleration parameter q = − ä aH 2 .…”