Work

Primordial Black Hole and Gravitational Wave by Peaked Cosmic Perturbations from Axion Curvaton

Year: 2026

Type: preprint

Abstract: We demonstrate that an axion field can develop perturbations peaked at an intermediate wavenumber through its inflationary dynamics. We compute the resultant spectrum of gravitational waves (GWs) and primordial black holes (PBHs) generated through the curvaton mechanism. The GW spectrum exhibits a triangular shape, with UV and IR slopes determined by the axion's inflationary evolution and treatable as free parameters. In computing the PBH abundance, we properly account for the nonlinear relation between curvature and density perturbations and the primordial non-Gaussianity generated by the curvaton. The PBHs can account for all of dark matter, accompanied by blue-tilted isocurvature perturbations at small scales. The IR slope of the GW spectrum is anti-correlated with the magnitude of the dark matter isocurvature perturbations, offering a multi-messenger test of the model.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2610.00457

Authors: Harigaya, Keisuke, Wang, Lian-Tao, Yi, Jiangyi

Institutions: Kavli Institute for the Physics and Mathematics of the Universe, University of Chicago, The University of Tokyo, The University of Tokyo Institutes for Advanced Study

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: U.S. Department of Energy, Ministry of Education, Culture, Sports, Science and Technology, Nankai University

OpenAlex ID: W7216165890

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