Non-minimally Coupled Tachyonic Inflation in Warped String Background

We show that the non-minimal coupling of tachyon field to the scalarcurvature, as proposed by Piao et al, with the chosen coupling parameter doesnot produce the effective potential where the tachyon field can roll down fromT=0 to large $T$ along the slope of the potential. We find a correct choice ofthe parameters which ensures this requirement and support slow-roll inflation.However, we find that the cosmological parameter found from the analysis of thetheory are not in the range obtained from observations. We then invoke warpedcompactification and varying dilaton field over the compact manifold, asproposed by Raeymaekers, to show that in such a setup the observed parameterspace can be ensured.Comment: minor typos corrected and references adde