Approximation of the potential in scalar field dark energy models

TL;DR

This paper investigates the potentials in scalar field dark energy models, providing an analytic approximation valid around the current epoch, which aids in reconstructing models from cosmological data.

Contribution

It introduces a simple analytic approximation for scalar field potentials in dark energy models with constant w_phi, applicable to both canonical and noncanonical kinetic terms.

Findings

Analytic approximation for potentials around scale factor a≈1

Approximation valid for 0.6≲a≲1.4

Potential form useful for reconstructing non-constant w_phi models

Abstract

We study the nature of potentials in scalar field based models for dark energy - with both canonical and noncanonical kinetic terms. We calculate numerically, and using an analytic approximation around $a\approx 1$, potentials for models with constant equation-of-state parameter, $w_{\phi}$. We find that for a wide range of models with canonical and noncanonical kinetic terms there is a simple approximation for the potential that holds when the scale factor is in the range $0.6\lesssim a\lesssim 1.4$. We discuss how this form of the potential can also be used to represent models with non-constant $w_{\phi}$ and, hence, how it could be used in reconstruction from cosmological data.