Norcia Matthew A, Poli Elena, Politi Claudia, Klaus Lauritz, Bland Thomas, Mark Manfred J, Santos Luis, Bisset Russell N, Ferlaino Francesca
Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria.
Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria.
Phys Rev Lett. 2022 Jul 22;129(4):040403. doi: 10.1103/PhysRevLett.129.040403.
Angular oscillations can provide a useful probe of the superfluid properties of a system. Such measurements have recently been applied to dipolar supersolids, which exhibit both density modulation and phase coherence, and for which robust probes of superfluidity are particularly interesting. So far, these investigations have been confined to linear droplet arrays, which feature relatively simple excitation spectra, but limited sensitivity to the effects of superfluidity. Here, we explore angular oscillations in systems with 2D structure which, in principle, have greater sensitivity to superfluidity. In both experiment and simulation, we find that the interplay of superfluid and crystalline excitations leads to a frequency of angular oscillations that remains nearly unchanged even when the superfluidity of the system is altered dramatically. This indicates that angular oscillation measurements do not always provide a robust experimental probe of superfluidity with typical experimental protocols.
角振荡可以为系统的超流性质提供一个有用的探测手段。此类测量最近已应用于偶极超固体，偶极超固体既表现出密度调制又表现出相位相干性，对于其而言，超流性的稳健探测手段尤其令人感兴趣。到目前为止，这些研究局限于线性液滴阵列，其具有相对简单的激发光谱，但对超流效应的灵敏度有限。在这里，我们探索具有二维结构的系统中的角振荡，原则上，这种系统对超流性具有更高的灵敏度。在实验和模拟中，我们发现超流激发与晶体激发的相互作用导致角振荡频率即使在系统的超流性发生显著变化时仍几乎保持不变。这表明，采用典型的实验方案时，角振荡测量并不总是能提供一个对超流性的稳健实验探测手段。
