Department of Physics and Center for Supersolid and Quantum Matter Research, KAIST, Daejeon 305-701, Republic of Korea.
Science. 2010 Dec 10;330(6010):1512-5. doi: 10.1126/science.1196409. Epub 2010 Nov 18.
Supersolidity, the appearance of zero-viscosity flow in solids, was first indicated in helium-4 torsional oscillator (TO) experiments. In this apparatus, the irrotationality of the superfluid component causes it to decouple from the underlying normal solid, leading to a reduction in the resonant period of the TO. However, the resonant period may be altered for reasons other than supersolidity, such as the temperature dependence of the elastic modulus of solid helium. Superimposing rotation onto oscillatory measurements may distinguish between supersolidity and classical effects. We performed such simultaneous measurements of the TO and the shear modulus, and observed substantial change in the resonant period with rotational speed where the modulus remained unchanged. This contrasting behavior suggests that the decrease in the TO period is a result of supersolidity.
超流固态性，即固体中出现零粘性流动的现象，最初在氦-4 扭摆振荡器 (TO) 实验中被观察到。在该装置中，超流部分的无旋性使其与下方的正常固体解耦，导致 TO 的共振周期缩短。然而，共振周期可能会因其他原因而发生变化，例如固体氦弹性模量随温度的变化。在振荡测量中叠加旋转可能会区分超流固态性和经典效应。我们对 TO 和剪切模量进行了这种同时测量，并观察到在模量不变的情况下，共振周期随转速的显著变化。这种对比行为表明，TO 周期的减小是超流固态性的结果。
