Observational constraints on complex quintessence with attractive self-interaction

TL;DR

This paper explores a complex scalar field model for dark energy with self-interaction, analyzing its late-time behavior and observational constraints, and suggests future models with multiple fields for early universe dynamics.

Contribution

It introduces a complex scalar field dark energy model with self-interaction, analyzing its late-time behavior and observational constraints, highlighting limitations of current data.

Findings

Model behaves as a cosmological constant in late times

Current observations cannot constrain the scalar field parameters effectively

Single-field models may be insufficient for early universe dynamics

Abstract

In this paper we consider that dark energy could be described solely by a complex scalar field with a Bose-Einstein condensate-like potential (denoted as CSFDE), that is, with a self-interaction and a mass term. In particular, we analyse a solution which in a fast oscillation regime at late-times behaves as a Cosmological Constant. Our proposal adequately describes the standard homogeneous and flat Fridman dynamics, furthermore, in this quintessence--complex scalar field scenario it is possible to mimic the dynamics related to dark energy. However, when the precision cosmological tests are implemented in this landscape, the generic Equation-of-State derived for this model in a restricted regime of a_i (which corresponds to the scale factor at which the scalar field turns on), cannot be constrained by late-time current observations, since the analysis constraints solely the scalar field parameters within values ruled out by the theoretical model. This result is a clear hint to consider future CSFDE models with, for instance, two scalar fields in order to study the early-time dynamics of the Universe.