  After simplifying and improving the non-Gaussian formalism we developed in
previous work, we derive a quantitative expression for the three-point
correlator (bispectrum) of the curvature perturbation in general multiple-field
inflation models. Our result describes the evolution of non-Gaussianity on
superhorizon scales caused by the nonlinear influence of isocurvature
perturbations on the adiabatic perturbation during inflation. We then study a
simple quadratic two-field potential and find that when slow roll breaks down
and the field trajectory changes direction in field space, the non-Gaussianity
can become large. However, for the simple models studied to date, the magnitude
of this non-Gaussianity decays away after the isocurvature mode is converted
into the adiabatic mode.
