We are working to build cryogenic quantum sensors such as transition edge sensors (TES). The philosophy is to keep a superconductor film just below its superconductor critical temperature, most of the time around the O(mK-K) range, and the film is attached to an absorber crystal. If there is any recoil in the absorber nuclei which increases their temperature (by even the tiniest fraction), the TES should be able to measure the change. In that sense, it can be used for a very sophisticated thermometer.
This technology will be useful to detect low-mass (<1 GeV) dark matter (DM), where the recoil energy in the absorber due to a scattering with the DM can be very low.