Non-Gaussianities in Multifield Inflation: Superhorizon Evolution,
  Adiabaticity, and the Fate of fnl
  We explore the superhorizon generation of large fnl of the local form in two
field inflation. We calculate the two- and three-point observables in a general
class of potentials which allow for an analytic treatment using the delta N
formalism. Motivated by the conservation of the curvature perturbation outside
the horizon in the adiabatic mode and also by the observed adiabaticity of the
power spectrum, we follow the evolution of fnl^{local} until it is driven into
the adibatic solution by passing through a phase of effectively single field
inflation. We find that although large fnl^{local} may be generated during
inflation, such non-gaussianities are transitory and will be exponentially
damped as the cosmological fluctuations approach adiabaticity.
