Deriving super-horizon curvature perturbations from the dynamics of
  preheating
  We present a framework for calculating super-horizon curvature perturbation
from the dynamics of preheating, which gives a reasonable match to the lattice
results. Hubble patches with different initial background field values evolve
differently. From the bifurcation of their evolution trajectories we find
curvature perturbation using Lyapunov theorem and $\delta N$ formulation. In
this way we have established a connection between the finer dynamics of
preheating and the curvature perturbation produced in this era. From the
calculated analytical form of the curvature perturbation we have derived the
effective super-horizon curvature perturbation smoothed out on large scales of
CMB. The order of the amount of local form non-gaussianity generated in this
process has been calculated and problems regarding the precise determination of
it have been pointed out.
