Dark Matter Direct Detection with Accelerometers
  The mass of the dark matter particle is unknown, and may be as low as
~$10^{-22}$ eV. The lighter part of this range, below ~eV, is relatively
unexplored both theoretically and experimentally but contains an array of
natural dark matter candidates. An example is the relaxion, a light boson
predicted by cosmological solutions to the hierarchy problem. One of the few
generic signals such light dark matter can produce is a time-oscillating,
EP-violating force. We propose searches for this using accelerometers, and
consider in detail the examples of torsion balances, atom interferometry, and
pulsar timing. These approaches have the potential to probe large parts of
unexplored parameter space in the next several years. Thus such accelerometers
provide radically new avenues for the direct detection of dark matter.
