Abstract
We investigate the three types of class B Bianchi cosmologies filled with a tilted perfect fluid undergoing velocity diffusion in a scalar field background. We consider the two most important cases: dust and radiation. A complete numerical integration of the Einstein field equations coupled with the diffusion equations is done to demonstrate how the presence of diffusion can affect the dynamics of cosmological evolution, where the most attention is paid to changes to the late-time behaviour. We show that aside from quantitative effects, diffusion can result in significant qualitative differences. For example, the Universe may recollapse if diffusion is sufficiently strong, or evolve towards the de Sitter state otherwise. In constrast to the diffusionless case, radiation isotropizes in the presence of diffusion, and the tilt decreases exponentially at later times: ; also, we determine the decay rates of energy density, which become slower when the diffusion term is non-zero.
Submitted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call