In this thesis the numerical calculation of non-Gaussianity from inflation
is discussed. Despite a strong interest in non-Gaussianity from inflation
models in recent years, not much attention has been devoted to its numerical
computation. Calculating the inflationary bispectrum in an efficient and
accurate manner will become more important as observational constraints
on primordial non-Gaussianity continue to increase.
Despite this, attention given to numerically calculating the primordial
bispectrum has been relatively low. The approach presented here differs
from previous approaches in that the Hubble Slow-Roll (HSR) parameters
are treated as the fundamental parameters. This allows one to calculate the
bispectra for a variety of scales and shapes in the out-of-slow-roll regime
and makes the calculation ideally suited for Monte-Carlo sampling of the
bispectrum.
The work is further extended to include potentials with features and non-
canonical kinetic terms, where the standard squeezed limit consistency re-
lation is demonstrated even for models which produce large f NL in the
equilateral limit. The method presented here is also independent of the
standard field redefinition used in analytic calculations, removing the need
for delicate cancellations in the super-horizon limit used in other numerical
methods.