Classical Non-Gaussianity From Non-Linear Evolution of Curvature Perturbation
Gong, Jinn-Ouk (CERN)

We show that in a single component situation all perturbation variables in the comoving gauge are conformally invariant to all perturbation orders. Generally we identify a special gauge, the uniform-conformal transformation gauge, where all perturbations are again conformally invariant to all perturbation orders. We apply this result to the delta N formalism, and show its conformal invariance. We argue that we can discuss the conformal invariance in the gauge transformations.