Superfluid Dynamics and Critical Phenomena

[9623694]本课程将探讨三个主题，阐述无序条件下超流体物理的不同方面：液氦在多孔（Vycor）玻璃中的超流体转变，特别是在转变时的热容异常的测量，这将需要低温量热法技术的重大进展。多孔介质中的耗散超流。该系统作为一个高tc超导体的玻色子模拟，其中涡旋流体和通量流动的理解在技术上是重要的。3. 在4He的第二层中发现了吸附在石墨上的超流体相，这是一种需要进一步研究的独特相。超流氦被用来阐明凝聚态物理中普遍感兴趣的问题。杂质和结构缺陷对“临界现象”和其他性能的影响将被检查。在多孔介质中，液氦的结构作为一种“淬火杂质”，对其进行研究，可以为理解凝聚态系统的无序性这一基本问题提供有价值的见解和测试。＊＊＊

9623694 Reppy Threee topics will be pursued which illustrate different aspects of superfluid physics under conditions of disorder: 1. The superfluid transition of liquid helium in porous (Vycor) glass, specifically a measurement of the heat capacity anomaly at the transition - for which a major advance in the art of low-temperature calorimetry will be required 2. Dissipative superflow in porous media. The system serves as a boson analog of a high-Tc superconductor, in which the understanding of the vortex fluid and the flux flow is of technically important. 3. The superfluid phase found in the second layer of 4He adsorbed on graphite - a unique phase that calls for further investigation. %%% Superfluid helium is employed to illuminate problems of general interest in condensed-matter physics. The effect of impurities and structural defects on "critical phenomena" and other properties will be examined. The study of liquid helium contained in a porous medium, where the structure acts as a "quenched impurity", can provide valuable insights and tests for understanding the fundamental problem of disorder in condensed-matter systems. ***