Inflection Point Quintessence

TL;DR

This paper explores scalar field models with inflection point potentials as a mechanism for cosmic acceleration, analyzing conditions for eternal or transient acceleration and their observational signatures.

Contribution

It introduces and analyzes simple and complex inflection point scalar field models, detailing their dynamics and compatibility with observed cosmic acceleration.

Findings

Models can produce both eternal and transient acceleration.

Parameter space maps identify conditions for  behavior.

Some models mimic  with transient acceleration.

Abstract

We examine models in which the accelerated expansion of the universe is driven by a scalar field rolling near an inflection point in the potential. For the simplest such models, in which the potential is of the form V(\phi) = V_0 + V_3 (\phi-\phi_0)^3, the scalar field can either evolve toward \phi = \phi_0 at late times, yielding an asymptotic de Sitter expansion, or it can transition through the inflection point, producing a transient period of acceleration. We determine the parameter ranges which produce each of these two possibilities and also map out the region in parameter space for which the equation of state of the scalar field is close to -1 at all times up to the present, mimicking \LambdaCDM. We show that the latter can be consistent with either eternal or transient acceleration. More complicated inflection point models are also investigated.