Angular oscillations in a 2D supersolid of Dysprosium*

When cooled to quantum degeneracy, gases of dipolar atoms, such as dysprosium, can spontaneously form a modulated many-body state, while simultaneously exhibiting global phase coherence: the supersolid phase. There is great interest in the direct observation of superfluid flow of such a state. For non-modulated superfluids the scissors mode can be directly connected to the moment of inertia and shows an increased frequency compared to classical rigid-body rotation. We probed the response of linear, “zig-zag” and hexagonal supersolid states to small angle rotations and observe a rich excitation spectrum. Our work shows that deducing the moment of inertia from a supersolid state requires knowledge of the full excitation spectrum, motivating further investigation and development of more elaborate excitation schemes to preferentially excite the low frequency modes.