Dynamical friction in gravitational atoms

Abstract Due to superradiant instabilities, clouds of ultralight bosons can spontaneously grow around rotating black holes, creating so-called “gravitational atoms”. In this work, we study their dynamical effects on binary systems. We first focus open orbits, showing that the presence a cloud increase cross section for capture compact object by more than an order magnitude. then consider closed orbits and demonstrate backreaction cloud's ionization orbital motion should be identified as friction. Finally, time eccentric inclined orbits. find that, while quickly circularizes binary, it barely affects inclination angle. These results enable realistic description dynamics gravitational atoms in binaries pave way dedicated searches with future wave detectors.