Violent Events in Superfluid 3Helium and a Collective Model of Glasses

将研究超流体氦中涉及剧烈偏离平衡和/或强烈非线性耗散的各种类型的现象。这类问题的例子有：结构和体磁化跟随移动的a - b界面的方式，移动的奇异涡的耗散，质量和自旋超流中的约瑟夫森效应，以及超流体3氦- b中导线在极低温度下振动的动力学。将有意识地尝试为这类问题发展中级的现象学概念，而不是依靠现有的微观技术。同时，我们也将尝试将玻璃的热学和声学特性发展成一个定量的理论。该方案是基于这样一种想法，即在大亚体积的应力变量的声子介导的相互作用中寻求玻璃性质中引人注目的普遍性的基本原理。人们希望这样的模型将取代目前在低温下建立的“隧穿两级系统”模型，并且还可以解释许多中高温行为，例如热导率的平台，这被认为与声子诱导相互作用的延迟性质开始发挥重要作用的点相对应。

A study will be made of various types of phenomenon in superfluid 3helium which involve violent departures from equilibrium and/or strongly nonlinear dissipation. Examples of such problems are the way in which textures and bulk magnetization follow the moving A-B interface, dissipation by moving singular vortices, the Josephson effect in both mass and spin supercurrent flow, and the dynamics of a wire vibrating in superfluid 3helium-B at very low tempertures. A conscious attempt will be made to develop intermediate-level, phenomenological concepts for this type of problem, rather than relying on existing microscopic technology. Also an attempt will be made to develop into a quantitative theory a collective scenario for the thermal and acoustic properties of glasses. The scenario is based on the idea that the underlying principle of the striking universality in glassy properties is to be sought in the phonon-mediated interactions of the stress variables of large subvolumes. It is hoped that such a model will replace the currently established "tunnelling two- level system" model at low tempertures, and in addition explain much of the intermediate- and high-temperature behavior, such as the plateau in the thermal conductivity, which is believed to correspond to the point at which the retarded nature of the phonon-induced interaction begins to play a substantial role.