Non-gaussianity of inflationary field perturbations from the field equation

Abstract

We calculate the tree-level bispectrum of the inflaton field perturbation directly from the field equations, and construct the corresponding f_NL parameter. Our results agree with previous ones derived from the Lagrangian. We argue that quantum theory should only be used to calculate the correlators when they first become classical a few Hubble times after horizon exit, the classical evolution taking over thereafter.

16 pages, uses iopart.sty. v2: replaced with version accepted by JCAP; minor changes of wording only. v3: supersedes version published by journal; typo fixed in Eq. (20) and updated references. v4: sign errors in Eqs. (32) and (38) corrected

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Cited by in corpus (10)

• The shape of primordial non-Gaussianity and the CMB bispectrum
• Cosmological Fluctuations from Infra-Red Cascading During Inflation
• Cosmology With Many Light Scalar Fields: Stochastic Inflation and Loop Corrections
• Primordial Non-Gaussianities of General Multiple Field Inflation
• On the Issue of the ζSeries Convergence and Loop Corrections in the Generation of Observable Primordial Non-Gaussianity in Slow-Roll Inflation. Part I: the Bispectrum
• Numerical calculation of second order perturbations
• A Tree Theorem for Inflation
• Tachyon Mediated Non-Gaussianity
• Magnetogenesis and the primordial non-gaussianity
• Revisiting non-Gaussianity of multiple-field inflation from the field equation