Primordial Black Holes from Inflation and non-Gaussianity

Primordial black holes may owe their origin to the small-scale enhancement of the comoving curva- ture perturbation generated during inflation. Their mass fraction at formation is markedly sensitive to possible non-Gaussianities in such large, but rare fluctuations. We discuss a path-integral formu- lation which provides the exact mass fraction of primordial black holes at formation in the presence of non-Gaussianity. Through a couple of classes of models, one based on single-field inflation and the other on spectator fields, we show that restricting to a Gaussian statistics may lead to severe inac- curacies in the estimate of the mass fraction as well as on the clustering properties of the primordial black holes.