Dark Matter Simulations with Primordial Black Holes in the Early
  Universe
  Primordial Black Holes (PBH) with masses of order $10-30 M_\odot$ have been
proposed as a possible explanation of the gravitational waves emission events
recently discovered by the LIGO observatory. If true, then PBHs would
constitute a sizeable fraction of the dark matter component in the Universe.
Using a series of cosmological N-body simulations which include both dark
matter and a variable fraction of PBHs ranging from $f_{PBH} = 10^{-4}$ to
$f_{PBH} = 1$, we analyse the processes of formation and disruption of
gravitationally bound PBH pairs, as well as the merging of both bound and
unbound pairs, and estimate the probabilities of such events. We show that they
are in good agreement with the constrains to the PBH abundance obtained by the
LIGO and other research groups. We find that pair stability, while being a main
factor responsible for the merger rate, is significantly affected by the
effects of dark matter halo formation and clustering. As a side result, we also
evaluate the effects of numerical errors in the stability of bound pairs, which
can be useful for future research using this methodology.
