Non-minimally coupled tachyon field with Noether symmetry under the Palatini approach

Abstract

A model for a homogeneous, isotropic, flat Universe composed by dark energy and matter is investigated. Dark energy is considered to behave as a tachyon field, which is non-minimally coupled to gravity. The connection is treated as metric independent when varying the action, providing an extra term to the Lagrangian density. The self-interaction potential and coupling are naturally found by imposing a Noether symmetry to the system. We analyze the evolution of the density parameters and we compare the results obtained for the deceleration parameter, luminosity distance and Hubble parameter with those found in literature from observational data.