The transient and the late time attractor tachyon dark energy: Can we distinguish it from quintessence ?

TL;DR

This paper investigates tachyon dark energy models inspired by string theory, analyzing their late-time behavior and how they compare to quintessence, especially near the present epoch where their behaviors are indistinguishable.

Contribution

It demonstrates that tachyon dark energy models can mimic thawing quintessence near the current epoch, highlighting challenges in distinguishing these models observationally.

Findings

Tachyon models exhibit late-time attractor behavior depending on potential decay rate.

Near the present epoch, tachyon and quintessence models show identical behavior.

Distinctive features of tachyon models emerge only at earlier or much later times.

Abstract

The string inspired tachyon field can serve as a candidate of dark energy. Its equation of state parameter $w$ varies from 0 to -1. In case of tachyon field potential $V(\phi)\to 0$ slower(faster) than $1/\phi^2$ at infinity, dark energy(dark matter) is a late time attractor. We investigate the tachyon dark energy models under the assumption that $w$ is close to -1. We find that all the models exhibit unique behavior around the present epoch which is exactly same as that of the thawing quintessence.