Fundamental Physics Seminar Series - Survival of the Fittest: Testing Superradiance Termination with Simulated Binary Black Hole Statistics

Abstract

The superradiance instability of rotating black holes leads to the formation of an ultralight boson cloud with distinctive observational signatures, making black holes an effective probe of ultralight dark matter. However, around black holes in a binary system, the superradiance effect of such clouds can be terminated by tidal perturbations from the companion, leading to cloud depletion. In this study, we perform the first analysis of the impact of this termination effect on superradiant black hole binaries which are realistically modelled after their statistics in our Galaxy. Working with a dataset of approximately 10^7 black hole binaries simulated using the Stellar Evolution for N-body (SEVN) population synthesis code, we identify the superradiant candidates and those that manage to survive the termination effect. We then calculate the cloud survival rate for various boson masses and black hole spin models. Our findings reveal that the l = m = 1 cloud modes are generally stable against termination, whereas the l = m = 2 modes can be significantly affected, with survival rates dropping below 10% for boson masses below approximately 0.5 × 10^{−12} eV. In addition, our analysis indicates that clouds that overcome termination typically exhibit a higher superradiant growth rate and therefore a higher detectability.


About the Speaker

Dr. ZHU Huiyu is currently a Postdoc researcher in Korea Institute for Basic Science. She finished her Ph.D. at Hong Kong University of Science and Technology. Her supervisors are Prof WANG Yi and Prof. George SMOOT. She received her Bachelor's degree from Southern University of Science and Technology at 2019 supervised by Prof. Leonardo MODESTO. Her research interest is on cosmology and Black Hole physics.


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