Cuckoo's Eggs in Neutron Stars: Can LIGO Hear Chirps from the Dark
  Sector?
  We explore in detail the possibility that gravitational wave signals from
binary inspirals are affected by a new force that couples only to dark matter
particles. We discuss the impact of both the new force acting between the
binary partners as well as radiation of the force carrier. We identify numerous
constraints on any such scenario, ultimately concluding that observable effects
on the dynamics of binary inspirals due to such a force are not possible if the
dark matter is accrued during ordinary stellar evolution. Constraints arise
from the requirement that the astronomical body be able to collect and bind at
small enough radius an adequate number of dark matter particles, from the
requirement that the particles thus collected remain bound to neutron stars in
the presence of another neutron star, and from the requirement that the theory
allows old neutron stars to exist and retain their charge. Thus, we show that
any deviation from the predictions of general relativity observed in binary
inspirals must be due either to the material properties of the inspiraling
objects themselves, such as a tidal deformability, to a true fifth force
coupled to baryons, or to a non-standard production mechanism for the dark
matter cores of neutron stars. Viable scenarios of the latter type include
production of dark matter in exotic neutron decays, or the formation of compact
dark matter objects in the early Universe that later seed star formation or are
captured by stars.
