On Stochastic Effects and Primordial Black-Hole Formation
  The effect of large quantum fluctuations on primordial black-hole formation
during an inflationary phase along a plateau is investigated. By using
techniques of stochastic inflation in combination with replica field theory and
the Feynman-Jensen variational method, it is non-perturbatively demonstrated
that the abundance of primordial black holes is amplified by several orders of
magnitude as compared to the classical computation.
