Bianchi type IX asymptotical behaviours with a massive scalar field: chaos strikes back

TL;DR

This study investigates the asymptotic behavior of Bianchi type IX cosmological models with a massive scalar field, revealing that oscillatory singularities can occur even with positive energy density, unlike the massless case.

Contribution

It extends previous analyses by examining the impact of a massive scalar field on Bianchi IX models, showing that oscillatory singularities can persist with positive energy density.

Findings

Oscillatory approach may exist with a massive scalar field.

Behavior depends on the scalar field's mass and energy density.

Contrasts with massless scalar field cases.

Abstract

We use numerical integrations to study the asymptotical behaviour of a homogeneous but anisotropic Bianchi type IX model in General Relativity with a massive scalar field. As it is well known, for a Brans-Dicke theory, the asymptotical behaviour of the metric functions is ruled only by the Brans-Dicke coupling constant with respect to the value -3/2. In this paper we examine if such a condition still exists with a massive scalar field. We also show that, contrary to what occurs for a massless scalar field, the singularity oscillatory approach may exist in presence of a massive scalar field having a positive energy density.