Superinflation, quintessence, and nonsingular cosmologies

TL;DR

This paper explores a cosmological model with a nonminimally coupled scalar field, revealing new behaviors like superinflation and nonsingular origins, which could explain dark energy phenomena.

Contribution

It introduces a detailed phase space analysis of a universe with a nonminimally coupled scalar field, highlighting novel dynamical behaviors not previously documented.

Findings

Identification of superinflation ($\,\dot{H}>0$)

Avoidance of big bang singularities

Spontaneous entry and exit from inflation

Abstract

The dynamics of a universe dominated by a self-interacting nonminimally coupled scalar field are considered. The structure of the phase space and complete phase portraits are given. New dynamical behaviors include superinflation ($\dot{H}>0$), avoidance of big bang singularities through classical birth of the universe, and spontaneous entry into and exit from inflation. This model is promising for describing quintessence as a nonminimally coupled scalar field.