Scalar Field Cosmologies with Barotropic Matter: Models of Bianchi class B

TL;DR

This paper analyzes Bianchi type B cosmological models with a barotropic fluid and scalar field, focusing on their long-term behavior, isotropization, and the prevalence of scaling solutions.

Contribution

It provides a detailed qualitative analysis of the asymptotic behavior and isotropization of these models, highlighting the conditions for inflation and scaling solutions.

Findings

Models can isotropize and inflate at late times.

Scaling solutions are generically present in the models.

Asymptotic behavior depends on matter and scalar field parameters.

Abstract

We investigate in detail the qualitative behaviour of the class of Bianchi type B spatially homogeneous cosmological models in which the matter content is composed of two non-interacting components; the first component is described by a barotropic fluid having a gamma-law equation of state, whilst the second is a non-interacting scalar field (phi) with an exponential potential V=Lambda exp(k phi). In particular, we study the asymptotic properties of the models both at early and late times, paying particular attention on whether the models isotropize (and inflate) to the future, and we discuss the genericity of the cosmological scaling solutions.