Such oscillators had been used to hunt for superfluidity because quantum materials, when placed in a spinning container, don’t spin along. Imagine rotating a bucket of water. If the water were a superfluid, it wouldn’t slosh around with the rotation but would instead sit unmoving, decoupled from the bucket’s moving sides. Supersolids, if they exist, would do the same thing. Thus, as a solid transitions to a supersolid state at low temperatures, the period of time it takes for the oscillator to rotate back and forth would drop — because less mass would be sloshing around."