Work

Unpolarized Low-Frequency Tail of Causal Chiral Gravitational Waves

Year: 2026

Type: preprint

Abstract: Parity violation in the early Universe may lead to a chiral gravitational wave background. We show that, for finite-time parity-violating sources, the low-frequency tail of the generated chiral gravitational wave background is universally unpolarized, and that the chirality fraction decreases linearly with frequency. Our result generally applies to any parity-violating gravitational-wave source that appears quadratically in the wave equation. We consider both Gaussian sources and explicit trispectrum templates. We attribute the lack of chirality of the low-frequency tail to the fact that, on large scales, gravitational wave generation is almost equally inefficient for both helicities.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2609.28828

Authors: Chabour, Tikinas, Domènech, Guillem, Ganz, Alexander, Tränkle, Jan

Institutions: Leibniz University Hannover, Max Planck Institute for Gravitational Physics

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: École Normale Supérieure, Deutsche Forschungsgemeinschaft, Japan Society for the Promotion of Science

Award: Das primordiale Universum mit Gravitationswellen erforschen

OpenAlex ID: W7214307681

Cites: 68

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Related to: 10