Assisted inflation in Friedmann-Robertson-Walker and Bianchi spacetimes

TL;DR

This paper demonstrates that in certain cosmological models, multiple scalar fields can enhance the likelihood of inflation when uncoupled, but interactions among fields tend to suppress inflation, with findings supported by exact solutions.

Contribution

It provides exact solutions showing how uncoupled and interacting scalar fields influence inflation probability in FRW and Bianchi spacetimes, extending previous power-law results.

Findings

Uncoupled scalar fields promote inflation in flat and Bianchi I spacetimes.

Interacting scalar fields hinder inflation occurrence.

Power-law solutions in Bianchi VI$_0$ are attractors, supporting the conclusions.

Abstract

We use exact general solutions for the spatially flat FRW and the anisotropic Bianchi I cosmologies to show that generically uncoupled scalar fields cooperate to make inflation more probable, while the presence of several interacting fields hinders the occurrence of the phenomenon, in accordance with previous results based on particular power-law solutions. Similar conclusions are reached in the case of Bianchi VI$_0$ spacetimes, for power-law solutions which are proved to be attractors.