Black hole binaries and light fields: Gravitational molecules

We show that light scalars can form quasibound states around binaries. In the nonrelativistic regime, these are formally described by quantum-mechanical Schr\"odinger equation for a one-electron heteronuclear diatomic molecule. performed extensive numerical simulations of scalar fields black hole binaries, showing structure condenses binary---we dub ``gravitational molecules.'' further well perturbative, description.