Enhanced tidal disruption rates from massive black hole binaries
  "Hard" massive black hole (MBH) binaries embedded in steep stellar cusps can
shrink via three-body slingshot interactions. We show that this process will
inevitably be accompanied by a burst of stellar tidal disruptions, at a rate
that can be several orders of magnitude larger than that appropriate for a
single MBH. Our numerical scattering experiments reveal that: 1) a significant
fraction of stars initially bound to the primary hole are scattered into its
tidal disruption loss cone by gravitational interactions with the secondary
hole, an enhancement effect that is more pronounced for very unequal-mass
binaries; 2) about 25% (40%) of all strongly interacting stars are tidally
disrupted by a MBH binary of mass ratio q=1/81 (q=1/243) and eccentricity 0.1;
and 3) two mechanisms dominate the fueling of the tidal disruption loss cone, a
Kozai non-resonant interaction that causes the secular evolution of the stellar
angular momentum in the field of the binary, and the effect of close encounters
with the secondary hole that change the stellar orbital parameters in a chaotic
way. For a hard MBH binary of 10^7 solar masses and mass ratio 0.01, embedded
in an isothermal stellar cusp of velocity dispersion sigma*=100 km/s, the tidal
disruption rate can be as large as 1/yr. This is 4 orders of magnitude higher
than estimated for a single MBH fed by two-body relaxation. When applied to the
case of a putative intermediate-mass black hole inspiraling onto Sgr A*, our
results predict tidal disruption rates ~0.05-0.1/yr.
