  We have performed cosmological N-body simulations which include the effect of
the masses of the individual neutrino species. The simulations were aimed at
studying the effect of different neutrino hierarchies on the matter power
spectrum. Compared to the linear theory predictions, we find that
non-linearities enhance the effect of hierarchy on the matter power spectrum at
mildly non-linear scales. The difference between the different hierarchies is
about 0.5% for a sum of neutrino masses of 0.1eV. Albeit this is a small
effect, it is potentially measurable from upcoming surveys. In combination with
neutrinoless double-beta decay experiments, this opens up the possibility of
using the sky to determine if neutrinos are Majorana or Dirac fermions.
