Third Sound Study of Pinned Vortices

小行星9322389 技术摘要：第三类声波将被用于研究超流4He薄膜在低温下的涡旋性质。 这些涡最近已被证明存在于超流过渡，钉在基板和稳定对温和的薄膜流。 大振幅的第三声波不仅提供足够大的膜流来移动涡旋，而且能够通过涡旋的量子力学类比来创建和破坏涡旋。 小振幅波被用来探测涡的分布。 对涡旋钉扎和产生的详细研究将有助于更好地理解低温下固有涡旋的重要性及其性质。 非技术摘要：本研究将探讨超流氦薄膜中微观量子化循环态的性质。 这些漩涡已被证明在超流转变温度附近的薄膜特性中发挥作用，并将首次在较低温度下通过与声波的相互作用直接研究。 与对应的超导性不同，在超流态的微观描述中仍然存在基本问题，澄清涡旋在薄膜中的作用将有助于对凝聚态物理的一般理解。 ***

9322389 Ellis Technical abstract: Third sound waves will be used to study the properties of vortices in superfluid 4He films at low temperatures. These vortices have been recently shown to exist well below the superfluid transition, pinned to the substrate and stable against moderate film flow. Large amplitude third sound waves not only provide film flow large enough to move the vortices, but are able to create and destroy the vortices by the quantum-mechanical analogy of swirling. Small amplitude waves are used to probe the vortex distribution. This detailed study of vortex pinning and creation will provide better understanding of the importance of innate vortices at low temperatures and their properties. Non-technical abstract: This research will investigate the properties of microscopic quantized circulation states in thin films of superfluid helium. These vortices have been shown to play a role in the properties of films near the superfluid transition temperature and will be studied directly for the first time at lower temperatures by their interaction with sound waves. Unlike its counterpart superconductivity, there remain fundamental problems in the microscopic description of the superfluid state and clarifying the role of the vortices in films will contribute to the general understanding of condensed matter physics. ***