Intermediate inflation driven by DBI scalar field

Abstract

Picking out DBI scalar field as inflation, the slow-rolling inflationary scenario is studied by attributing an exponential time function to scale factor; known as intermediate inflation. The perturbation parameters of the model are estimated numerically for two different cases and the final result is compared with Planck data. The diagram of tensor-to-scalar ratio $r$ versus scalar spectra index $n_s$ is illustrated, and it is found out that they are in acceptable range, as suggested by Planck. In addition, the acquired values for amplitude of scalar perturbation reveals the ability of the model for depicting a good picture of the universe in one of the earliest stage. As a further argument, the non-Gaussianity is investigated displaying that the model prediction stands in $68\%$ CL regime; according to latest Planck data.