Critical Phenomena Near the Superfluid Transition of 4He

4He 超流转变附近的临界现象

• 批准号: 9217577
• 负责人: Guenter Ahlers
• 金额: $ 48.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1996-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9217577&HistoricalAwards=false
• 关键词: Critical; Phenomena; Near; Superfluid; Transition

Investigations of the superfluid (sf) transition in liquid helium 4: 1) Study helium containing aerogels as an impurity, measuring the thermal expansion and thermal conductivity. Data on the concentration and pressure dependences will illuminate the relationship between the phase transitions in the pure and impure systems. 2) Study the propagation of second sound near the sf transition in the presence of superfluid and normal-fluid velocity fields, to test the correctness of a recent theory. %%% Quantum mechanics underlies and governs the behavior of all matter. Liquid helium is almost unique in being a substance which behaves as a quantum mechanical system on a macroscopic scale. Studies such as are here proposed can be expected to advance their understanding of quantum physics, as well as phase transitions and the special properties of porous materials.

液氦中超流体 (sf) 转变的研究 4： 1) 研究含有杂质的气凝胶的氦，测量热膨胀和导热率。 有关浓度和压力依赖性的数据将阐明纯系统和不纯系统中相变之间的关系。 2) 研究在超流体和正常流体速度场存在的情况下，第二声在 sf 转变附近的传播，以测试最新理论的正确性。 %%% 量子力学是所有物质行为的基础并支配着它们。 液氦几乎是独一无二的，因为它是一种在宏观尺度上表现为量子力学系统的物质。 这里提出的研究有望增进他们对量子物理学以及相变和多孔材料特殊性质的理解。