Effective Field Theories in Inflation - 2009

We estimate the size of loop corrections in various inflationary systems and determine the region of parameter space where the perturbation theory around a quasi de Sitter background is strongly coupled. In some models, we argue that backreaction to the inflatonary background become important before the erturbations become strongly coupled while in others, there seems to exist a legitimate strongly coupled but still inflating regime. We also demonstrate that loop effects could be dominant in the bispectrum while still having a well controlled perturbation theory and we explore the phenomenological implications.

Abstract: In this talk a model of inflation is presented where the inflaton fields are non-commutative matrices. The spectrum of adiabatic and iso-curvature perturbations and their implications on CMB are studied. It is argued that our model of matrix inflation can naturally be embedded in string theory.