A New Probe of Dark Matter-Induced Fifth Force with Neutron Star
  Inspirals
  A light scalar dark matter (DM) is allowed in a wide range of the mass and
interaction types. We show that the light scalar DM may be probed in a new way
from final years of neutron-star (NS) binary inspirals. If the DM interacts
with the neutron, its long wave coherence in the background can induce the
time-oscillating mass shift, to which the binary inspiral is inherently
sensitive. But the sensitivity is found to be significantly enhanced by a large
number of gravitational-wave (GW) cycles during year-long highest-frequency
measurements in the broadband $f \simeq 0.01-1000$ Hz. The future broadband
detector networks including LIGO-band detectors can probe unconstrained
parameter space of the light scalar DM.
