Primordial Black Holes from Multifield Inflation with Nonminimal
  Couplings
  Primordial black holes (PBHs) provide an exciting prospect for accounting for
dark matter. In this paper, we consider inflationary models that incorporate
realistic features from high-energy physics -- including multiple interacting
scalar fields and nonminimal couplings to the spacetime Ricci scalar -- that
could produce PBHs with masses in the range required to address the present-day
dark matter abundance. Such models are consistent with supersymmetric
constructions, and only incorporate operators in the effective action that
would be expected from generic effective field theory considerations. The
models feature potentials with smooth large-field plateaus together with
small-field features that can induce a brief phase of ultra-slow-roll
evolution. Inflationary dynamics within this family of models yield predictions
for observables in close agreement with recent measurements, such as the
spectral index of primordial curvature perturbations and the ratio of power
spectra for tensor to scalar perturbations. As in previous studies of PBH
formation resulting from a period of ultra-slow-roll inflation, we find that at
least one dimensionless parameter must be highly fine-tuned to produce PBHs in
the relevant mass-range for dark matter. Nonetheless, we find that the models
described here yield accurate predictions for a significant number of
observable quantities using a smaller number of relevant free parameters.
