Observational constraint on the dark energy scalar field

TL;DR

This paper uses Gaussian processes to analyze background and perturbation data, suggesting dark energy is dynamic and favoring the quintom scalar field, while disfavouring the tachyon field as a dark energy candidate.

Contribution

It introduces a novel application of Gaussian processes to reconstruct scalar field potentials and compare different dark energy models using observational data.

Findings

Dark energy is likely dynamical according to reconstructions.

Quintom field is strongly favored within 68% confidence level.

Tachyon scalar field is not convincingly supported by the data.

Abstract

In the present paper, we investigate three scalar fields, \qu field, phantom field and tachyon field, to explore the source of dark energy, using the Gaussian processes method from the background data and perturbation growth rate data. The corresponding reconstructions all suggest that the dark energy should be dynamical. Moreover, the quintom field, a combination between \qu field and phantom field, is powerfully favored by the data within 68\% confidence level. Using the mean values of scalar field $\phi$ and potential $V$, we fit the function $V(\phi)$ in different fields. The fitted results imply that potential $V(\phi)$ in each scalar field may be a double exponential function or Gaussian function. The Gaussian processes reconstructions also indicate that the tachyon scalar field cannot be convincingly favored by the data and is at a disadvantage to describe the dark energy.