Primordial Black Holes from Inflation and Quantum Diffusion

TL;DR

This paper investigates how quantum diffusion affects the formation of primordial black holes during inflation, challenging classical predictions and emphasizing the importance of stochastic effects in early universe models.

Contribution

It introduces the impact of quantum diffusion on primordial black hole production during non-attractor inflation phases, highlighting limitations of classical predictions.

Findings

Quantum diffusion significantly alters black hole mass fraction predictions.

Classical models may overestimate primordial black hole abundance.

Stochastic effects are crucial in accurate early universe modeling.

Abstract

Primordial black holes as dark matter may be generated in single-field models of inflation thanks to the enhancement at small scales of the comoving curvature perturbation. This mechanism requires leaving the slow-roll phase to enter a non-attractor phase during which the inflaton travels across a plateau and its velocity drops down exponentially. We argue that quantum diffusion has a significant impact on the primordial black hole mass fraction making the classical standard prediction not trustable.