Numerical relativity simulation of inspiraling binary black holes with massive scalar condensate clouds

Massive scalar fields in the vicinity of a rotating black hole may form condensates, e.g., due to the superradiant instability or due to accretion. These scalar fields may represent wave-like dark matter candidates or axion-like particles proposed in the string axiverse. In a binary black hole system the presence of such scalar condensates may lead to an enriched dynamical evolution, additional scalar (dipole) radiation and imprints in the gravitational wave emission. We will report on new numerical relativity simulations for which we construct constraint satisfying initial data and self-consistently solve the Einstein-Klein-Gordon equations. We then discuss implications of our results for gravitational-wave observations.