Qualitative Analysis of Isotropic Curvature String Cosmologies

TL;DR

This paper provides a comprehensive qualitative analysis of string cosmologies with isotropic curvature, focusing on Bianchi types I, V, and IX, including effects of two-form potentials and cosmological constants.

Contribution

It offers the first complete qualitative study of these models, highlighting the roles of two-form potentials, curvature, and cosmological constants in their dynamics.

Findings

Two-form potential and curvature are important at intermediate stages.

Cosmological constant dominates asymptotically, reducing anisotropy.

Existence of bouncing cosmological solutions.

Abstract

A complete qualitative study of the dynamics of string cosmologies is presented for the class of isotopic curvature universes. These models are of Bianchi types I, V and IX and reduce to the general class of Friedmann-Robertson-Walker universes in the limit of vanishing shear isotropy. A non-trivial two-form potential and cosmological constant terms are included in the system. In general, the two-form potential and spatial curvature terms are only dynamically important at intermediate stages of the evolution. In many of the models, the cosmological constant is important asymptotically and anisotropy becomes dynamically negligible. There also exist bouncing cosmologies.