Assisted coupled quintessence

TL;DR

This paper explores models of coupled quintessence with multiple scalar fields and dark matter components, deriving effective parameters, analyzing transient solutions, and providing evolution equations for perturbations to facilitate observational testing.

Contribution

It introduces a simplified description of multi-field coupled quintessence models and derives their perturbation evolution equations for observational comparison.

Findings

Scaling solutions can be described by a single effective field.

Effective parameters depend on individual slopes and couplings.

Perturbation equations enable testing against data.

Abstract

We study models of quintessence consisting of a number of scalar fields coupled to several dark matter components. In the case of exponential potentials the scaling solutions can be described in terms of a single field. The corresponding effective logarithmic slope and effective coupling can be written in a simple form in terms of the individual slopes and couplings of the original fields. We also investigate solutions where the scalar potential is negligible, in particular those leading to transient matter dominated solutions. Finally, we compute the evolution equations for the linear perturbations which will allow these models to be tested against current and future observational data.