Violent Events in Superfluid Three-Helium and a Collective Model of Glasses

超流三氦中的暴力事件和眼镜的集体模型

• 批准号: 9214236
• 负责人: Anthony Leggett
• 金额: $ 27万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1996-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9214236&HistoricalAwards=false
• 关键词: Violent; Events; Superfluid; Three; Helium

A theoretical study will be carried out on various phenomena in superfluid helium-three in which the liquid is thrown violently out of thermal equilibrium and must then recover. In particular, in light of the recent discovery of Osheroff and Schiffer that a gamma ray scource is an efficient nucleator of the first order A to B transition, it is planned to elaborate the "baked Alaska" mechanism for nucleation of this transition by high energy electrons which was suggested earlier and to make detailed predictions of the dependence of the nucleation rate on temperature and on magnetic field. In addition, studies are planned of the nuclear magnetic resonance behavior in the highly supercooled A phase in low field, with a view to obtaining previously unavailable microscopic parameters of the liquid. It is also proposed to develop further a collective model of amorphous materials for explaining the remarkable quantitative universlaity of the thermal and acoustic properties of these materials at low temperatures. %%% Theoretical research will be conducted in two areas for which the Principal Investigator is the world leader: (1) research will continue on models for amorphous materials to explain the common properties that occur at very low temperatures among diverse materials; (2) work will continue on models for the violent behavior of helium at very low temperatures. This behavior has recently been observed and a theory, introduced earlier, will be further developed in light of these recent and exciting experimental discoveries.

将对超流氦三中的各种现象进行理论研究，其中液体被猛烈地抛离热平衡，然后必须恢复。 特别是，鉴于Osheroff和Schiffer最近发现伽马射线源是一阶A到B跃迁的有效成核剂，计划详细阐述先前提出的高能电子在此跃迁中成核的“烘烤阿拉斯加”机制，并对成核速率对温度和磁场的依赖性进行详细预测。 此外，还计划研究低场下高度过冷A相的核磁共振行为，以获得以前无法获得的液体微观参数。 还建议进一步开发非晶材料的集体模型，以解释这些材料在低温下的热和声学性能的显着的定量通用性。 %%% 理论研究将在两个领域进行，首席研究员在这两个领域处于世界领先地位：（1）将继续研究非晶材料模型，以解释不同材料在极低温度下出现的共同特性； (2) 将继续研究氦在极低温度下的剧烈行为模型。 最近已经观察到了这种行为，并且根据这些最近令人兴奋的实验发现，将进一步发展之前引入的理论。