Stochastic gravitational-wave background from self-interacting superradiant clouds
Abstract
Gravitational-wave (GW) observations offer a powerful probe of new fundamental fields. One well-motivated source is black hole (BH)--boson cloud systems, in which an ultralight scalar field forms a cloud around a rotating BH via superradiance and emits long-lived nearly monochromatic GWs. In this work, we compute the stochastic GW background (SGWB) from such systems, extending previous work by including scalar self-interactions, and discuss its detectability with next-generation ground-based GW detectors. We find that self-interactions can suppress the SGWB and thereby relax existing LIGO-Virgo-KAGRA constraints inferred from null searches. Namely, the LIGO detectors at design sensitivity are insensitive to a SGWB produced by scalar fields with a decay constant fs ≲ 3× 1017 GeV, independently of the scalar field mass. Looking ahead, we show that a moderately self-interacting cloud can still produce a detectable SGWB with next-generation detectors. Under conservative assumptions, for a decay constant fs = 1017 GeV, the Einstein Telescope (ET) will be sensitive to scalar masses in the range ∼[10−13.0,10−11.8] eV, while Cosmic Explorer (CE) will be sensitive to scalar masses in the range ∼[10−13.2,10−11.7] eV. We also find that the minimum decay constants that still yield a detectable SGWB for ET and CE are fs∼ 6×1016GeV and ∼ 3×1016GeV, respectively.
Related
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- Modeling Uncertainties in Modified Gravity Predictions for the Stochastic Gravitational-Wave Background
BibTeX
@misc{guo2026stochastic,
title = {{Stochastic gravitational-wave background from self-interacting superradiant clouds}},
author = {Yin-Da Guo and Richard Brito and Chen Yuan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.33596},
eprint = {2609.33596},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.33596},
}
RIS
TY - UNPB
TI - Stochastic gravitational-wave background from self-interacting superradiant clouds
AU - Yin-Da Guo
AU - Richard Brito
AU - Chen Yuan
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2609.33596
UR - https://arxiv.org/abs/2609.33596
AB - Gravitational-wave (GW) observations offer a powerful probe of new fundamental fields. One well-motivated source is black hole (BH)--boson cloud systems, in which an ultralight scalar field forms a cloud around a rotating BH via superradiance and emits long-lived nearly monochromatic GWs. In this work, we compute the stochastic GW background (SGWB) from such systems, extending previous work by including scalar self-interactions, and discuss its detectability with next-generation ground-based GW detectors. We find that self-interactions can suppress the SGWB and thereby relax existing LIGO-Virgo-KAGRA constraints inferred from null searches. Namely, the LIGO detectors at design sensitivity are insensitive to a SGWB produced by scalar fields with a decay constant f_s ≲ 3× 10^17 GeV, independently of the scalar field mass. Looking ahead, we show that a moderately self-interacting cloud can still produce a detectable SGWB with next-generation detectors. Under conservative assumptions, for a decay constant f_s = 10^17 GeV, the Einstein Telescope (ET) will be sensitive to scalar masses in the range ∼[10^−13.0,10^−11.8] eV, while Cosmic Explorer (CE) will be sensitive to scalar masses in the range ∼[10^−13.2,10^−11.7] eV. We also find that the minimum decay constants that still yield a detectable SGWB for ET and CE are f_s∼ 6×10^16GeV and ∼ 3×10^16GeV, respectively.
ER -