Warm-tachyon Gauss–Bonnet inflation in the light of Planck 2015 data

Abstract

We study a warm-tachyon inflationary model non-minimally coupled to a Gauss–Bonnet term. The general conditions required for reliability of the model are obtained by considerations of a combined hierarchy of Hubble and Gauss–Bonnet flow functions. The perturbed equations are comprehensively derived in the longitudinal gauge in the presence of slow-roll and quasi-stable conditions. General expressions for observable quantities of interest such as the tensor-to-scalar ratio, scalar spectral index and its running are found in the high dissipation regime. Finally, the model is solved using exponential and inverse power-law potentials, which satisfy the properties of a tachyon potential, with parameters of the model being constrained within the framework of the Planck 2015 data. We show that the Gauss–Bonnet coupling constant controls termination of inflation in such a way as to be in good agreement with the Planck 2015 data.