Primordial black holes and induced gravitational waves from double-pole inflation

TL;DR

This paper introduces a novel double-pole inflation model that naturally produces primordial black holes and detectable gravitational waves with less fine-tuning, offering rich observational signatures and potential dark matter candidates.

Contribution

It proposes a new asymmetric double-pole inflation model that simplifies PBH production and predicts distinctive gravitational wave signals for future detection.

Findings

Enhanced small-scale curvature perturbations with ultraviolet oscillations.

PBHs can account for dark matter, microlensing events, and LIGO-Virgo detections.

Induced gravitational waves are detectable by future space-based and pulsar timing detectors.

Abstract

The primordial black hole (PBH) productions from the inflationary potential with an inflection point usually rely heavily on the fine-tuning of the model parameters. We propose in this work a new kind of the $\alpha$-attractor inflation with asymmetric double poles that naturally and easily lead to a period of non-attractor inflation, during which the PBH productions are guaranteed with less fine-tuning the model parameters. This double-pole inflation can be tested against the observational data in the future with rich phenomenological signatures: (1) the enhanced curvature perturbations at small scales admit a distinctive feature of ultraviolet oscillations in the power spectrum; (2) the quasi-monochromatic mass function of the produced PBHs can be made compatible to the asteroid-mass PBHs as the dominant dark matter component, the planet-mass PBHs as the OGLE ultrashort-timescale microlensing events, and the solar-mass PBHs as the LIGO-Virgo events; (3) the induced gravitational waves can be detected by the gravitational-wave detectors in space and Pulsar Timing Array/Square Kilometer Array.