Speaker
Description
Ultralight bosons, such as axion-like particles, are promising candidates for physics beyond the Standard Model. Rotating black holes can amplify these fields through superradiance, forming macroscopic bosonic clouds known as gravitational atoms. In this work, we investigate the evolution of ultralight boson clouds in binary black hole systems, considering their full evolutionary history from large orbital separations to the late inspiral stage. We show that the common-envelope phase in astrophysical binary evolution can significantly enhance cloud survival by suppressing resonant depletion, expanding the parameter space accessible to future space-based gravitational-wave detectors. We further identify a novel mass-transfer mechanism of boson clouds driven by binary tidal interactions, which arises from the wave nature of the bosonic field and does not require superradiance around the companion object. At small separations, we demonstrate the transition from gravitational atoms to bosonic common envelopes and show that their backreaction can excite binary eccentricity to observable levels. These results provide a unified picture of boson cloud evolution in binary systems and reveal new possibilities for probing ultralight particles through gravitational-wave observations.