Cosmological perturbations in warm-tachyon inflationary universe model with viscous pressure on the brane

Abstract

We study warm-viscous inflationary universe model on the brane, in a tachyon field theory. We obtain the general conditions which are required for this model to be realizable. In longitudinal gauge, the primoradial perturbation parameters are found in great details, using slow-roll and quasi-stable approximations. The general expressions of the tensor-to-scalar ratio, scalar spectral index and its running are found. We derive the characteristics of the inflationary universe model by using an effective exponential potential in two cases: 1- Dissipative parameter $\Gamma$ and bulk viscous parameter $\zeta$ are constant parameters. 2- Dissipative parameter as a function of tachyon field $\phi$ and bulk viscous parameter as a function of radiation-matter mixture energy density $\rho$. The parameters of the model are restricted by recent observational data from the seven-year Wilkinson microwave anisotropy probe (WMAP7).