About one-point statistics of ratio of two Fourier transformed cosmic
  fields and an application
  The Fourier transformation is an effective and efficient operation of
Gaussianization at the one-point level. Using a set of N-body simulation data,
we verified that the one-point distribution functions of the dark matter
momentum divergence and density fields closely follow complex Gaussian
distributions. Statistical theories about the one-point distribution function
of the quotient of two complex Gaussian random variables are introduced and
applied to model one-point statistics about the growth of individual Fourier
mode of the dark matter density field, namely the mode-dependent growth
function and the mode growth rate, which can be obtained by the ratio of two
Fourier transformed cosmic fields. Our simulation results proved that the
models based on the Gaussian approximation are impressively accurate, and our
analysis revealed many interesting aspects about the growth of dark matter's
density fluctuation in Fourier space.
