Prokof'ev Nikolay, Svistunov Boris
Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Phys Rev Lett. 2005 Apr 22;94(15):155302. doi: 10.1103/PhysRevLett.94.155302. Epub 2005 Apr 20.
We prove that the necessary condition for a solid to be also a superfluid is to have zero-point vacancies, or interstitial atoms, or both, as an integral part of the ground state. As a consequence, in the absence of symmetry between vacancies and interstitials, superfluidity has a zero probability to occur in commensurate solids which break continuous translation symmetry. We discuss recent 4He experiments by Kim and Chan in the context of this theorem, question its bulk supersolid interpretation, and offer an alternative explanation in terms of superfluid interfaces.
我们证明，一种固体同时成为超流体的必要条件是具有零点空位、间隙原子或两者兼而有之，作为基态的一个组成部分。因此，在空位和间隙原子之间不存在对称性的情况下，在破坏连续平移对称性的整比固体中，超流性出现的概率为零。我们在该定理的背景下讨论了Kim和Chan最近关于4He的实验，对其体超固体解释提出质疑，并从超流体界面的角度给出了另一种解释。
