Primordial Black Holes from non-Gaussian tails
  We develop a primordial black hole (PBH) production mechanism, deriving
non-Gaussian tails from interacting quantum fields during early universe
inflation. The multi-field potential landscape may contain relatively flat
directions, as a result of energetically favorable adjustments of fields
coupled to the inflaton. Such additional fields do not contribute to CMB
fluctuations given a sufficient large-scale decay, related to a gap in the
critical exponents computed using stochastic methods. Along such directions
transverse to the inflaton, the field makes rare jumps to large values. Mixing
with the inflaton leads to a substantial tail in the resulting probability
distribution for the primordial perturbations. Incorporating a large number of
flavors of fields ensures theoretical control of radiative corrections and a
substantial abundance. This generates significant PBH production for a
reasonable window of parameters, with the mass range determined by the time
period of mixing and the inflationary Hubble scale. We analyze a particular
model in detail, and then comment on a broader family of models in this class
which suggests a mechanism for primordial seeds for early super-massive black
holes in the universe. Along the way, we encounter an analytically tractable
example of stochastic dynamics and provide some representative calculations of
its correlations and probability distributions.
