PT Journal
AU Figueroa, DG
   Raatikainen, S
   Rasanen, S
   Tomberg, E
TI Non-Gaussian Tail of the Curvature Perturbation in Stochastic Ultraslow-Roll Inflation: Implications for Primordial Black Hole Production
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2021
BP 101302
EP 7pp
VL 127
IS 10
DI 10.1103/PhysRevLett.127.101302
LA English
AB We consider quantum diffusion in ultraslow-roll (USR) inflation. Using the Delta N formalism, we present the first stochastic calculation of the probability distribution P(R) of the curvature perturbation during USR. We capture the nonlinearity of the system, solving the coupled evolution of the coarse-grained background with random kicks from the short wavelength modes, simultaneously with the mode evolution around the stochastic background. This leads to a non-Markovian process from which we determine the highly non-Gaussian tail of P(R). Studying the production of primordial black holes in a viable model, we find that stochastic effects during USR increase their abundance by a factor of similar to 10(5) compared with the Gaussian approximation.
ER