there and back again... a tale about two-field inflation and non-Gaussianity
Inflationary predictions for the power spectrum of the curvature
perturbation have been verified to an excellent degree, leaving many
models compatible with observations. Higher-order correlations, if
detected or constrained by Planck, will allow one to further distinguish
between inflationary models. In this talk I will review the theory of
gauge-invariant non-linear cosmological perturbations in the context of
two-field inflation as well as the properties of the local bispectrum
produced in these models. I will also present the methods I have
developed and used for this purpose, which are the long-wavelength
formalism and the cubic action of the adiabatic and isocurvature
perturbations, and illustrate their use with explicit applications.