Evidence of superfluidity in a dipolar supersolid

The elusive supersolid, an exotic quantum phase that combines the properties of a crystalline solid and those of a superfluid, has been recently discovered in a system of Bose-condensed strongly magnetic atoms. In this paper, I report on an experiment that directly demonstrates the superfluid behavior of the dipolar supersolid measuring its anomalous response to a rotational excitation. I complement the illustration of the experimental results with a review and an original interpretation of a seminal model due to Leggett.