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arXiv · 2501.11071

Probing Spin-2 Ultralight Dark Matter with Space-based Gravitational Wave Detectors in the mHz Regime

Jing-Rui Zhang·Ju Chen·Heng-Sen Jiao·Rong-Gen Cai·Yun-Long Zhang
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Abstract

Spin-2 ultralight dark matter (ULDM) is a viable dark matter candidate and it can be constrained using gravitational wave (GW) observations. In this paper, we investigate the detectability of spin-2 ULDM by space-based GW interferometers. By considering a direct coupling between spin-2 ULDM and ordinary matter, we derive the corresponding response functions and sensitivity curves for various time-delay interferometry channels and calculate the optimal sensitivity curves for future millihertz GW detectors. Our results demonstrate that the space-based detectors can place stringent constraints on the coupling constant of spin-2 ULDM, reaching $\alpha \sim 10^{-10}$ around a mass of $m \sim 10^{-17} \rm eV$, surpassing current limits from ground-based detectors and pulsar timing arrays. Thus, the space-based GW detectors can serve as powerful tools not only for detecting GWs but also for probing fundamental properties of ultralight dark matter.

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Jing-Rui Zhang, Ju Chen, Heng-Sen Jiao, Rong-Gen Cai, Yun-Long Zhang. 2025-01-19. Probing Spin-2 Ultralight Dark Matter with Space-based Gravitational Wave Detectors in the mHz Regime. https://doi.org/10.1103/cz2w-5cfj

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