Perturbations in Bianchi-V Spacetimes with Varying Λ, G and Viscous Fluids

Abstract

As a follow-up of a recent article in which we investigated the cosmological background expansion history of the universe in Bianchi type-V cosmological models with bulk viscous fluid and evolving cosmological Λ and Newtonian G parameters, we study the evolution of the cosmological perturbations in the current work. In particular, we analyse the evolution of the viscous matter over-density that leads to formation of large-scale structures in the Bianchi-V model, and compare the results with standard ΛCDM solutions. Our results suggest that introducing viscous fluid in the background described by Bianchi-V geometry with evolving Λ and G amplifies the structure-growth rate.