Stochastic Phenomena in Physics and Biology

物理和生物学中的随机现象

• 批准号: 9514853
• 负责人: Ronald Fox
• 金额: $ 9万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9514853&HistoricalAwards=false
• 关键词: Stochastic; Phenomena; Physics; Biology

Stochastic phenomena, the dynamical effects of thermal and molecular fluctuations, are of continuing interest in physics and biology. Our approach involves theory, numerical simulations and contact with experiments. In one part of the research, quantum mechanical consequences of chaotic dynamics in classical systems will be studied. Classical measures of fluctuation amplification by chaos, such as Lyapunov exponents, can be related to the growth rate of quantum variances in systems that can be described both classically and quantally. This connection will be explored in the context of magneto-optically trapped cesium atom experiments. This work leads to a reevaluation of fundamental classical concepts such as point and trajectory that turn out to be unstable characteristics of chaotic systems. In another part of the research, stochastic properties of the propagation of action potentials along neurons is explored. These studies provide a first principles account of ion channel fluctuations and their affects on action potential propagation, timing, and interspike statistics, each of which has been recently highlighted as of importance for the information coding problem in neuronal signals. The fluctuations cause spontaneous firing patterns that have been measured and which will be compared with numerical simulations of a stochastic theory.

随机现象，热和分子波动的动力学效应，一直是物理学和生物学的研究热点。我们的方法包括理论、数值模拟和接触实验。在研究的一部分中，将研究经典系统中混沌动力学的量子力学后果。混沌的涨落放大的经典度量，如李雅普诺夫指数，可以与系统中量子方差的增长率相关，这些系统可以被经典和量子描述。这种联系将在磁光俘获铯原子实验的背景下进行探讨。这项工作导致了一个基本的经典概念，如点和轨迹，原来是混沌系统的不稳定特征的重新评估。在另一部分研究中，探讨了动作电位沿神经元传播的随机特性。这些研究提供了离子通道波动及其对动作电位传播、时序和峰间统计的影响的基本原理，其中每一项最近都被强调为神经元信号中信息编码问题的重要性。波动引起的自发发射模式已被测量，并将与随机理论的数值模拟进行比较。