The inflation trilogy and primordial black holes

TL;DR

This paper introduces a novel inflation model with three stages—cold, warm, and thermal—driven by different scalar fields, which naturally produces primordial black holes that could account for dark matter.

Contribution

It presents a new multi-stage inflation scenario that generates a distinctive black hole mass spectrum and addresses dark matter composition.

Findings

Large density fluctuations from warm inflation lead to primordial black hole formation.

The model predicts a black hole mass gap due to thermal inflation.

Primordial black holes could constitute all dark matter within this framework.

Abstract

We propose an inflation scenario with three independent stages of cold, warm and thermal inflation, respectively, driven by different scalar fields, motivated by the large number of such fields predicted in most extensions of the Standard Model. We show, in particular, that the intermediate period of warm inflation naturally leads to large density fluctuations on small scales, which can lead to primordial black hole formation in the mass window where they may account for all dark matter. This type of scenario yields a distinctive primordial black hole mass function with a mass gap, with the final period of thermal inflation diluting the abundance of very light black holes.