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arXiv · 1110.2462

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

Yuki Watanabe
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Abstract

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 analytically find that the amplitude of f_{NL} decays no faster than a^{-3} as the inflationary trajectory reaches to the adiabatic limit for generic potentials.

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Yuki Watanabe. 2012-05-05. δN versus covariant perturbative approach to non-Gaussianity outside the horizon in multifield inflation. https://doi.org/10.1103/physrevd.85.103505

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