Theory of Large Fluctuations in Systems Away From Thermal Equilibrium

远离热平衡系统的大波动理论

• 批准号: 9722057
• 负责人: Mark Dykman
• 金额: $ 12.6万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9722057&HistoricalAwards=false
• 关键词: Theory; Large; Fluctuations; Systems; Away

Large fluctuations, although infrequent, play a fundamental role in a broad range of processes, from nucleation to failure of electronic devices. The proposed research aims to reach understanding of the dynamics of systems which perform large fluctuations, to investigate new large-fluctuation phenomena, and to find optimal ways of controlling fluctuations by external fields. For classical systems, the problem of the optimal (most probable) fluctuational paths will be formulated in terms of physically observable characteristics of the system and the driving noise. Generic singular features of the pattern of optimal paths will be revealed and analyzed as well as the related critical behavior of the distribution of fluctuational paths. Optimal paths in real time will be used to investigate quantum rates of escape from metastable periodic states and their singular behavior - the problem which is of topical interest for experiments and to which the standard notion of tunneling at a nearly constant energy does not apply.

大的波动虽然不常见，但在从成核到电子设备故障的广泛过程中发挥着重要作用。 所提出的研究旨在了解发生大波动的系统的动力学，研究新的大波动现象，并找到通过外部场控制波动的最佳方法。 对于经典系统，最优（最可能）波动路径的问题将根据系统的物理可观察特性和驱动噪声来制定。 将揭示和分析最佳路径模式的一般奇异特征以及波动路径分布的相关关键行为。 实时最优路径将用于研究从亚稳周期态逃逸的量子速率及其奇异行为——这个问题是实验的热门话题，但几乎恒定能量的隧道效应的标准概念并不适用。