Superhorizon Perturbations: Beyond deltaN formalism

The London Relativity and Cosmology Seminar
Yuichi Takamizu (Kyoto)
February 20th, 2013 at 16:30
Maths 103

We develop a theory of nonlinear cosmological perturbations on superhorizon scales for a single and multi-component scalar field with a general kinetic term and a general form of the potential in the context of inflationary cosmology. We employ the ADM formalism and the spatial gradient expansion approach.  This formalism can be applied to the superhorizon evolution of a primordial non-Gaussianity beyond the so-called delta N formalism valid up to the second order in the expansion.