# Primordial Black Holes from Inflation with Nonminimal Derivative Coupling

## TL;DR

This paper introduces a new inflation model with nonminimal derivative coupling that enhances curvature perturbations, enabling the formation of primordial black holes with specific mass spectra to explain various astrophysical phenomena.

## Contribution

It presents a novel mechanism for primordial black hole formation via a special coupling in inflation, producing a sharp mass spectrum matching observational data.

## Key findings

- Achieves sharp peaks in the power spectrum for PBH formation.
- Produces PBHs with masses around 10 solar masses, 10^-5 solar masses, and 10^-12 solar masses.
- Potentially explains LIGO events, microlensing, and dark matter.

## Abstract

We propose a novel enhancement mechanism of the curvature perturbations in the nonminimal derivative coupling inflation model with a coupling parameter related to the inflaton field. By considering a special form of the coupling parameter as a function of the inflaton, a period of ultra-slow-roll inflation can be realized due to the gravitationally enhanced friction, and the resulting power spectrum of the curvature perturbations has a sharp peak, which is large enough to produce the primordial black holes. Under this mechanism, we can easily obtain a sharp mass spectrum of primordial black holes around specific masses such as $\mathcal{O}(10)M_\odot$, $\mathcal{O}(10^{-5})M_\odot$, and $\mathcal{O}(10^{-12})M_\odot$, which can explain the LIGO events, the ultrashort-timescale microlensing events in OGLE data, and the most of dark matter, respectively.