Chaos in Robertson-Walker Cosmology

TL;DR

This paper investigates the emergence of homoclinic chaos in Robertson-Walker cosmological models with scalar fields, using analytical methods to complement previous numerical studies and exploring the effects of scalar field mass.

Contribution

It provides an analytical demonstration of homoclinic chaos in scalar field cosmology, extending understanding beyond numerical simulations and focusing on the impact of scalar field mass.

Findings

Homoclinic chaos arises for nonzero scalar field masses.

The model is integrable when the scalar field is massless.

Perturbative methods reveal the onset of chaos in the system.

Abstract

Chaos in Robertson-Walker cosmological models where gravity is coupled to one or more scalar fields has been studied by a few authors, mostly using numerical simulations. In this paper we begin a systematic study of the analytical aspect. We consider one conformally coupled scalar field and, using the fact that the model is integrable when the field is massless, we show in detail how homoclinic chaos arises for nonzero masses using a perturbative method.