Articles written in Pramana – Journal of Physics
Volume 88 Issue 4 April 2017 Article ID 0061 Research Article
The general class of Bianchi cosmological models with dark energy in the form of modified Chaplygin gas with variable $\Lambda$ and $G$ and bulk viscosity have been considered. We discuss three types of average scalefactor by using a special law for deceleration parameter which is linear in time with negative slope. The exact solutions to the corresponding field equations are obtained. We obtain the solution of bulk viscosity ($\xi$ ), cosmologicalconstant ($\Lambda$), gravitational parameter ($G$) and deceleration parameter ($q$) for different equations of state. The model describes an accelerating Universe for large value of time $t$ , wherein the effective negative pressure induced by Chaplygin gas and bulk viscous pressure are driving the acceleration.
Volume 92 Issue 5 May 2019 Article ID 0079 Research Article
In this paper, we have studied the locally rotationally symmetric (LRS) Bianchi type-I cosmological model filled with a bulk viscous cosmological fluid in $f(R)$ gravity in the presence of time-varying gravitational and cosmological constant. We have used the power-law and intermediate scenario for scale factor to obtain thesolution of the field equations. The evolution of temperature of a viscous Universe is also analysed.
Volume 96 All articles Published: 27 June 2022 Article ID 0123 Research Article
In this paper, we deal with a Finsler–Randers (FR) cosmology in the framework of particle creation mechanism. The cosmological history of the model is studied by finding all the critical points and analysing their local stability.We study the behaviour of all critical points of the model when they are non-hyperbolic in nature using the centre manifold theory. The perseverance of the equilibrium points are illustrated by showing the vector field locally near the equilibrium point. The possible bifurcation scenarios are discussed in detail with the help of local bifurcation diagrams for each of the critical points. Concluding remarks and the cosmological upshot are also given.
Volume 96, 2022
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