Primordial Black Hole Dark Matter and LIGO/Virgo Merger Rate from
  Inflation with Running Spectral Indices: Formation in the Matter- and/or
  Radiation-Dominated Universe
  We study possibilities to explain the whole dark matter abundance by
primordial black holes (PBHs) or to explain the merger rate of binary black
holes estimated from the gravitational wave detections by LIGO/Virgo. We assume
that the PBHs are originated in a radiation- or matter-dominated era from large
primordial curvature perturbation generated by inflation. We take a simple
model-independent approach considering inflation with large running spectral
indices which are parametrized by $n_\text{s}, \alpha_\text{s}$, and
$\beta_\text{s}$ consistent with the observational bounds. The merger rate is
fitted by PBHs with masses of $\mathcal{O}(10)$ $M_{\odot}$ produced in the
radiation-dominated era. Then the running of running should be $\beta_\text{s}
\sim 0.025$, which can be tested by future observation. On the other hand, the
whole abundance of dark matter is consistent with PBHs with masses of asteroids
($\mathcal{O}(10^{-17})~M_{\odot}$) produced in an early matter-dominated era
if a set of running parameters are properly realized.
