Scalar-induced gravitational waves and primordial black holes from a localized bump or dip feature in a single-field inflationary potential

TL;DR

This paper investigates how localized features in a single-field inflationary potential can simultaneously produce detectable gravitational waves and primordial black holes, aligning theoretical predictions with observational constraints.

Contribution

It introduces a model with a localized bump or dip in the inflationary potential that enhances curvature perturbations, leading to observable gravitational waves and black holes.

Findings

Primordial black hole abundances are compatible with current limits.

Gravitational wave spectra peak across multiple frequencies.

Model predictions are testable with future experiments.

Abstract

We study the production of scalar-induced gravitational waves and primordial black holes in a single-field inflation model with a localized bump or dip feature in the potential. Introducing such a localized feature temporarily decelerates the slow-roll inflaton, amplifying the primordial curvature power spectrum into a sharp peak. Consequently, this enhancement sources a significant stochastic background of gravitational waves and leads to abundant formation of primordial black holes. Through eight benchmark cases, we show that the predicted abundances of primordial black holes can remain compatible with current observational limits, while the corresponding gravitational wave spectra peaking across a wide range of frequencies are accessible to future gravitational wave experiments in multiple observational bands.