Evidence of superfluidity in a dipolar supersolid from nonclassical rotational inertia

Abstract

A supersolid rotation When a bucket of water is rotated, the water rotates with the vessel, contributing to the total moment of inertia. If such an experiment were done with a superfluid, it would decouple from the vessel and would not contribute to rotation. Tanzi et al. studied an intermediate case, a supersolid, which is predicted to only partially decouple, resulting in a moment of inertia smaller than the classical value. Whereas previous such experiments were done with helium, the authors used a gas of highly magnetic dysprosium atoms in an optical trapping potential that was suddenly changed, causing the gas to oscillate. Measuring the frequency of these oscillations provides evidence for a reduced moment of inertia. Science , this issue p. 1162