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arXiv · 2508.09567

Local Group Velocity Distribution inside Superradiant Condensates

Yin-Da Guo·Kai-Dong Zhou·Shou-Shan Bao·Hong Zhang
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Abstract

Superradiance enables scalar fields to extract energy and angular momentum from a rotating black hole (BH), leading to the formation of a BH-condensate system. Previous studies mainly focus on the phase velocity, which propagates in the azimuthal direction. In this work, we show that the superradiant scalar condensate presents a nontrivial group velocity distribution. In the region sufficiently far from the BH, the condensate exhibits a radial velocity magnitude that approaches $ (r_g\mu/2) \sin (2\omega t-2 \varphi)$, while the polar and azimuthal velocity magnitudes asymptotically decline as $\propto 1/r$.

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Yin-Da Guo, Kai-Dong Zhou, Shou-Shan Bao, Hong Zhang. 2025-08-13. Local Group Velocity Distribution inside Superradiant Condensates. https://doi.org/10.1016/j.physleta.2025.131316

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