1201.3163 (Teruaki Suyama et al.)

Fully non-linear equivalence of delta N and covariant formalisms    [PDF]

Teruaki Suyama, Yuki Watanabe, Masahide Yamaguchi

We explicitly show the fully non-linear equivalence of the $\delta$N and the covariant formalisms for the superhorizon curvature perturbations, which enables us to safely evaluate the non-Gaussian quantities of the curvature perturbation in either formalism. We also discuss isocurvature perturbations in the covariant formalism and clarify the relation between the fully non-linear evolution of the curvature covector and that of the curvature perturbation for multiple interacting fluids.

View original: http://arxiv.org/abs/1201.3163