Theory of Large Fluctuations in Systems Away From Thermal Equilibrium

大的波动虽然不常见，但在从成核到电子器件故障的广泛过程中起着重要作用。 拟议的研究旨在了解执行大波动的系统的动态，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。 揭示和分析最优路径模式的一般奇异特征，以及波动路径分布的相关临界行为。 真实的时间中的最优路径将被用来研究从亚稳态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，而在几乎恒定的能量下隧穿的标准概念并不适用于这个问题。

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.