Superradiant scattering by a black hole binary

Understand

I present evidence of a novel guise of superradiance that arises in black hole binary spacetimes.

• Given the right initial conditions, a wave will be amplified as it scatters off the binary.
• This process, which extracts energy from the orbital motion, is driven by absorption across the horizons and is most pronounced when the individual black holes are not spinning.
• Focusing on real scalar fields, I demonstrate how modern effective field theory (EFT) techniques enable the computation of the superradiant amplification factor analytically when there exist large separations of scales.