Gravitational wave as probe of superfluid dark matter
  In recent years, superfluid dark matter (SfDM) has become a competitive model
of emergent modified Newtonian dynamics (MOND) scenario: MOND phenomenons
naturally emerge as a derived concept due to an extra force mediated between
baryons by phonons as a result of axionlike particles condensed as superfluid
at galactic scales; Beyond galactic scales, these axionlike particles behave as
normal fluid without phonon-mediated MOND-like force between baryons, therefore
SfDM also maintains the usual success of $\Lambda$CDM at cosmological scales.
In this paper, we use gravitational waves (GWs) to probe the relevant parameter
space of SfDM. GWs through Bose-Einstein condensate (BEC) could propagate with
a speed slightly deviation from the speed-of-light due to the change in the
effective refractive index, which depends on the SfDM parameters and GW-source
properties. We find that Five hundred meter Aperture Spherical Telescope
(FAST), Square Kilometre Array (SKA) and International Pulsar Timing Array
(IPTA) are the most promising means as GW probe of relevant parameter space of
SfDM. Future space-based GW detectors are also capable of probing SfDM if a
multimessenger approach is adopted.
