Dynamics of Non-Equilibrium Systems and Theory of Quantum Fluids and Solids

非平衡系统动力学以及量子流体和固体理论

• 批准号: 8715474
• 负责人: Michael Cross
• 金额: $ 22.38万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-03-01 至 1991-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8715474&HistoricalAwards=false
• 关键词: Dynamics; Non; Equilibrium; Systems; Theory

Part of the study is a theoretical program to investigate the spatial structure and complex dynamics in non-equilibrium systems near the threshold of an instability at finite wavenumber. Considerable progress has been made for stationary instabilities, exemplified by convection in pure fluids. Experiments on convection in binary fluid mixtures provide the impetus for theoretical work on the rich behavior near the threshold of a dynamic instability. The methods to be used are perturbational schemes leading to "amplitude" and "phase" equations; numerical solution of the full fluid equations to answer specific questions; and the numerical simulation of simpler model equations constructed to capture the important physics near the instabilities. Although fluid systems provide convenient systems for a careful comparison between theory and experiment, the results should have wide applicability in diverse fields. The other part of the work will study bulk and interfacial Helium, both to understand the microscopic behavior of these simple but challenging model quantum systems, and to investigate them as laboratories for novel physics in new parameter regimes, where quantum effects dominate thermal, and collisional relaxation effects are often small. Monte-Carlo methods provide an important tool for investigating the microscopic physics, but must be tied in with analytic phenomenology to yield any real understanding. Interfacial Helium provides an interesting two- dimensional thermodynamic system, and has remarkable and experimentally vital transport behavior that remains poorly understood.

该研究的一部分是一个理论计划，旨在研究有限波数的不稳定性阈值附近的非平衡系统中的空间结构和复杂动力学。 对于固定不稳定性，已经取得了相当大的进步，以纯流体的对流为例。 二元流体混合物中对流的实验为动态不稳定性阈值附近的丰富行为提供了理论工作的动力。 要使用的方法是导致“振幅”和“相位”方程的扰动方案。全流体方程的数值解决方案，以回答特定问题；以及构建的简单模型方程的数值模拟，以捕获不稳定性附近的重要物理。 尽管流体系统提供了方便的系统，以仔细比较理论和实验，但结果应在不同领域具有广泛的适用性。 工作的另一部分将研究散装和界面氦气，以了解这些简单但具有挑战性的模型量子系统的微观行为，并将它们作为新参数方案中新型物理学的实验室进行调查，其中量子效应主导了热效应，碰撞弛豫效应通常很小。 蒙特卡罗方法为研究微观物理学提供了重要的工具，但必须与分析现象学相关，以产生任何真正的理解。 界面氦气提供了一个有趣的二维热力学系统，并且具有显着且实验至关重要的运输行为，但仍然知之甚少。