Hunt B, Pratt E, Gadagkar V, Yamashita M, Balatsky A V, Davis J C
Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA.
Science. 2009 May 1;324(5927):632-6. doi: 10.1126/science.1169512.
Although solid helium-4 (4He) may be a supersolid, it also exhibits many phenomena unexpected in that context. We studied relaxation dynamics in the resonance frequency f(T) and dissipation D(T) of a torsional oscillator containing solid 4He. With the appearance of the "supersolid" state, the relaxation times within f(T) and D(T) began to increase rapidly together. More importantly, the relaxation processes in both D(T) and a component of f(T) exhibited a complex synchronized ultraslow evolution toward equilibrium. Analysis using a generalized rotational susceptibility revealed that, while exhibiting these apparently glassy dynamics, the phenomena were quantitatively inconsistent with a simple excitation freeze-out transition because the variation in f was far too large. One possibility is that amorphous solid 4He represents a new form of supersolid in which dynamical excitations within the solid control the superfluid phase stiffness.
尽管固态氦 - 4（4He）可能是一种超固体，但它也展现出许多在这种情况下意想不到的现象。我们研究了包含固态4He的扭摆振荡器在共振频率f(T)和耗散D(T)中的弛豫动力学。随着“超固体”状态的出现，f(T)和D(T)中的弛豫时间开始一起迅速增加。更重要的是，D(T)和f(T)的一个分量中的弛豫过程都表现出朝着平衡的复杂同步超慢演化。使用广义旋转磁化率的分析表明，虽然表现出这些明显的玻璃态动力学，但这些现象在数量上与简单的激发冻结转变不一致，因为f的变化太大。一种可能性是无定形固态4He代表了一种新的超固体形式，其中固体内部的动态激发控制着超流相刚度。
