Some aspects of tachyon field cosmology

We study inflation, perturbations, non-Gaussianity, and late-time cosmological dynamics of a tachyon field both minimally and nonminimally coupled to gravity. By analyzing the parameter space of the model, the viability of the model in confrontation with recent observational data is considered. In a dynamical system technique, we study the phase space dynamics of both a minimally and nonminimally coupled tachyon field. We find the fixed points (lines in our setup) and explore their stability. Also, we perform a statefinder diagnostic to both cases and show that the trajectories of the statefinder pairs reach a stable state which corresponds to a Lambda cold dark matter scenario.