  We consider the use of quantum-limited mechanical force sensors to detect
ultralight (sub-meV) dark matter candidates which are weakly coupled to the
standard model. We show that mechanical sensors with masses around or below the
milligram scale, operating around the standard quantum limit, would enable
novel searches for dark matter with natural frequencies around the kHz scale.
This would complement existing strategies based on torsion balances, atom
interferometers, and atomic clock systems.
