Constraining non-minimally coupled tachyon fields by Noether symmetry

TL;DR

This paper uses Noether symmetry to determine the potential and coupling functions in a cosmological model with a non-minimally coupled tachyon field, analyzing its role in early inflation and late-time acceleration.

Contribution

It derives exponential forms for the potential and coupling functions using Noether symmetry and explores cosmological solutions for both early and late Universe scenarios.

Findings

Tachyon field acts as an inflaton during early Universe

Tachyon field drives late-time acceleration as dark energy

Exponential potential and coupling functions are consistent with symmetry constraints

Abstract

A model for a spatially flat homogeneous and isotropic Universe whose gravitational sources are a pressureless matter field and a tachyon field non-minimally coupled to the gravitational field is analyzed. Noether symmetry is used to find the expressions for the potential density and for the coupling function, and it is shown that both must be exponential functions of the tachyon field. Two cosmological solutions are investigated: (i) for the early Universe whose only source of the gravitational field is a non-minimally coupled tachyon field which behaves as an inflaton and leads to an exponential accelerated expansion and (ii) for the late Universe whose gravitational sources are a pressureless matter field and a non-minimally coupled tachyon field which plays the role of dark energy and is the responsible of the decelerated-accelerated transition period.