Super-Horizon Scale Dynamics of Multi-Scalar Inflation

Abstract

We consider the dynamics of a multi-component scalar field on super-horizon\nscales in the context of inflationary cosmology. We present a method to solve\nthe perturbation equations on super- horizon scales, i.e., in the long\nwavelength limit, by using only the knowledge of spatially homogeneous\nbackground solutions. In doing so, we clarify the relation between the\nperturbation equations in the long wavelength limit and the background\nequations. Then as a natural extension of our formalism, we provide a strategy\nto study super-horizon scale perturbations beyond the standard linear\nperturbation theory. Namely we reformulate our method so as to take into\naccount the nonlinear dynamics of the scalar field.\n