Formation of subhorizon black holes from preheating
  We study the production of primordial black holes (PBHs) during the preheating stage that follows a chaotic inflationary phase. The scalar fields present in the process are evolved numerically using a modified version of the HLATTICE code. From the output of the numerical simulation, we compute the probability distribution of curvature fluctuations, paying particular attention to sub-horizon scales. We find that in some specific models these modes grow to large amplitudes developing highly non-Gaussian probability distributions. We then calculate PBH abundances using the standard Press-Schechter criterion and find that overproduction of PBHs is likely in some regions of the chaotic preheating parameter space. 
E. Torres-Lomas, Juan Carlos Hidalgo, Karim A. Malik, L. Arturo   Ure\~na-L\'opez
astro-ph.CO gr-qc hep-th