1110.2462 (Yuki Watanabe)

δN versus covariant perturbative approach to non-Gaussianity outside the horizon in multifield inflation    [PDF]

Yuki Watanabe

We compute the super-Hubble evolution of non-Gaussianity of primordial curvature perturbations in two-field inflation models by employing two formalisms: delta N and covariant formalisms. Although two formalisms treat the evolution of fluctuations radically different, we show that the formulas of f_{NL} parameter agree quantitatively with each other within 1 % accuracy. We find that the amplitude of f_{NL} decays no faster than a^{-3} as the inflationary trajectory reaches to the adiabatic limit.

View original: http://arxiv.org/abs/1110.2462