Double inflation as a single origin of primordial black holes for all
  dark matter and LIGO observations
  Primordial Black Hole (PBH) is one of the leading non-particle candidates for
dark matter (DM). Although several observations severely constrain the amount
of PBHs, it is recently pointed out that there is an uncertainty on the
microlensing constraints below $\sim 10^{-10} M_\odot$ which was ignored
originally but may weaken the constraints significantly. In this paper, facing
this uncertainty, we investigate the possibility that PBHs can make up all DM
in a broad mass spectrum. Moreover, we propose a concrete inflation model which
can simultaneously produce PBHs for all DM in a broad mass spectrum around
$\mathcal O(10^{-13}) M_\odot$ and PBHs for LIGO events in a sharp mass
spectrum at $\mathcal O(10) M_\odot$.
