Two-field Kahler moduli inflation in large volume moduli stabilization

In this paper we present a two-field inflation model, which is distinctive in having a non-canonical kinetic Lagrangian and comes from the large volume approach to the moduli stabilization influx compactification of type IIB superstring on a Calabi-Yau orientifold with h((1,2)) > h((1,1)) >= 4. The Kahler moduli are classified as the volume modulus, heavy moduli and two light moduli. The axion-dilaton, complex structure moduli and all heavy Kahler moduli including the volume modulus are frozen by a non-perturbatively corrected flux superpotential and the alpha'-corrected Kahler potential in the large volume limit. The minimum of the scalar potential at which the heavy moduli are stabilized provides the dominant potential energy for the surviving light Kahler moduli. We consider a simplified case where the axionic components in the light Kahler moduli are further stabilized at the potential minimum and only the geometrical components are taken as scalar fields to drive an assisted-like inflation. For a certain range of moduli stabilization parameters and inflation initial conditions, we obtain a nearly. at power spectrum of the curvature perturbation, with n(s) approximate to 0.96 at Hubble exit, and an inflationary energy scale of 3 x 10(14) GeV. In our model, there is significant correlation between the curvature and isocurvature perturbations on super-Hubble scales, so at the end of inflation a great deal of the curvature power spectrum originates from this correlation.