Key points are not available for this paper at this time.
Recent pulsar timing array data suggest the presence of stochastic gravitational waves, implying a significant amplitude in curvature perturbations and thus a large abundance of primordial black holes (PBH). The latter is at odds with the observed constraints on the PBH abundance. The authors scrutinize in detail the standard calculation and approximations in determining the PBH abundance and point out several uncertainties, concluding that the PBH abundance is likely much smaller than what is the current consensus.
Luca et al. (Thu,) studied this question.