Is the formation of primordial black holes from single-field inflation compatible with standard cosmology?

TL;DR

This paper examines whether single-field inflation models can produce primordial black holes compatible with standard cosmology, highlighting the need for fine-tuning and detailed post-inflationary understanding, and introduces a new model for sub-solar PBHs.

Contribution

It demonstrates the conditions under which single-field inflation can generate primordial black holes and presents a new model consistent with observations for sub-solar PBHs.

Findings

Single-field inflation can produce PBHs with specific tuning.

A new double inflection point model generates sub-solar PBHs.

Potential detectability of PBH mergers by LVK.

Abstract

In this work, we investigate the generation of primordial black holes (PBHs) within the framework of single-field inflationary models and their compatibility with the cosmological history of the Universe. Our results suggest that, depending on the masses of the formed PBHs, single-field inflation models require more than fine-tuning a potential to induce ultra-slow roll; it necessitates a comprehensive understanding of the post-inflationary cosmological evolution. As an explicative example, we introduce a new model, based on a double inflection point and consistent with Cosmic Microwave Background observations, capable of generating sub-solar PBHs, whose merger could be potentially detectable by the LVK experiment.