Accelerating cosmologies with nonlinear electrodynamics

Abstract

In this paper, we consider the framework of nonlinear electrodynamics in locally rotationally symmetric (LRS) Bianchi-I universe model composed of magnetic fluid. It has been shown that an accelerated universe expansion takes place if the nonlinear electromagnetic field is a source of gravitational field. In this model, after the big bang, the universe undergoes inflation and the accelerated expansion, dissipates the initial anisotropy of the curvature part without using a selected initial condition. Further validity of generalised second law of thermodynamics in the cosmological model enclosed by apparent horizon is investigated. We also discuss the classical stability of the cosmological model and observational viability of the model.

Qualitative aspects of Rastall gravity with barotropic fluid

“…From thermodynamics point of view in cosmological scenario, the enveloping surface should be apparent horizon and not the event horizon [74]. Apparent horizon as universe's boundary have been used in literature for examining the validity of GSLT in different cosmological set-ups [19,23,25,52,55,57,61,73,74]. In flat-FRW universe, radius of apparent horizon is related with Hubble parameter as R a = 1 H .…”

“…Eling et al [45] demonstrated that by using terms other than Einstein-Hilbert action, one may produce entropy due to the non-equilibrium thermodynamical aspects of generalized f (R) theory [46]. By using field equations and applying thermodynamical laws to cosmological horizon, one can find rate of total horizon entropy in different gravitational setups [12,15,19,23,[47][48][49][50][51][52][53][54][55][56][57]. The behaviour of expanding universe have also been studied extensively from the thermodynamic point of view.…”