Stochastic and Nonlinear Phenomena in Physics and Biology

物理和生物学中的随机和非线性现象

• 批准号: 9819646
• 负责人: Ronald Fox
• 金额: $ 13.5万
• 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: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9819646&HistoricalAwards=false
• 关键词: Stochastic; Nonlinear; Phenomena; Physics; Biology

The focus of this research proposal is the interplay of stochasticity and nonlinearity in physics and biology. Two projects are in physics and have their origin in earlier studies by the Principal Investigator on the amplification of intrinsic noise by chaos. Two projects are in biology and concern the fundamental constructive role of noise in molecular and cellular mechanisms. Each project involves a combination of methods. Analytic and numerical methods will be used, and contact with experiments will be made wherever possible. One project of each type is described below.1) The classical Lyapunov exponent has been shown by the Principal Investigator to be a quantum signature of classical chaos. This realization depends on the use of Husimi-Wigner distributions that have direct classical analogues as non-negative ensemble densities. Husimi-Wigner wave packets are most easily constructed using generalized coherent states. In this proposal, a new class of coherent states called Klauder states will be studied. Especially interesting are the Klauder states for the Coulomb problem. This work will impact research on quantum-classical correspondence and on experiments with Rydberg atom traps. 2) Rectified Brownian movement is a mechanism by which metabolic Gibbs free energy is converted into useful mechanical work inside cells. Rather than a direct chemo-mechanical conversion in which chemical energy is transduced into work, an indirect mechanism is proposed. In this alternative mechanism, work is done by heat, but not in violation of the second law of thermodynamics. Instead, a diffusion regime is applicable in which the boundary conditions are asymmetric. The asymmetry is paid for with metabolic free energy. The impact of this work will be to potentially provide a unified mechanism for a great many basic cellular processes.

本研究计划的重点是物理学和生物学中随机性和非线性的相互作用。 两个项目是在物理学和起源于早期的研究由首席研究员对混沌放大固有噪声。 两个项目是在生物学和关注的基本建设性作用的噪音在分子和细胞机制。每一个项目都涉及到方法的组合。 分析和数值方法将被使用，并与实验接触将尽可能。每种类型的一个项目如下所述。1）经典李雅普诺夫指数已被首席研究员证明是经典混沌的量子签名。 这种实现依赖于使用具有直接经典类似物作为非负系综密度的Husimi-Wigner分布。 Husimi-Wigner波包最容易用广义相干态构造。 在这个方案中，我们将研究一类新的相干态，称为Klauder态。特别有趣的是库仑问题的Klauder状态。这项工作将影响量子经典对应的研究和里德伯原子陷阱的实验。2)修正布朗运动是一种机制，通过该机制，代谢吉布斯自由能在细胞内转化为有用的机械功。 而不是一个直接的化学机械转换，其中化学能转化为工作，提出了一个间接的机制。 在这种替代机制中，功是通过热来完成的，但不违反热力学第二定律。相反，扩散制度是适用的边界条件是不对称的。 这种不对称性是用代谢自由能来补偿的。这项工作的影响将可能为许多基本的细胞过程提供统一的机制。