Behavior of Large Random Systems

大型随机系统的行为

• 批准号: 9419362
• 负责人: Joshua Deutsch
• 金额: $ 18.7万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-15 至 1998-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419362&HistoricalAwards=false
• 关键词: Behavior; Large; Random; Systems

9419362 Deutsch Research is proposed in three areas of theoretical statistical physics. (1) Studies of nonequilibrium processes which possess large fluctuations. The objective is to better understand the structures which arise in fully developed turbulence by using a simulation technique that selects large, but unlikely fluctuations. The results should provide an improved understanding of turbulent intermittency. (2) Structural prediction for macromolecules. Prediction of structure and morphology is important in the understanding of materials and biomaterials, but requires knowing the forces between the individual building blocks of the systems. The large experimental data base on protein structure will be used to systematically determine the force field that acts between different atoms or constituent submolecules. The results will be important in determining structures of macromolecules. (3) Quantum simulations using statistical methods. A large class of problems is difficult to simulate due to sign changes during averaging processes. This class of problems is of fundamental and current interest. A method will be studied which greatly speeds up this averaging process by replacing the sudden change in sign by a continuously varying phase. The consideration of the statistics of these phases leads to improved methods for doing these averages. %%% Theoretical research involving advanced computational techniques will be done on a variety of problems dealing with very large random systems. One problem will develop new methods to better determine the structure of biologically important macromolecules. Another project will deal with new algorithms to surmount a fundamental problem involving calculations of physical systems of interacting electrons. The solution of this problem can have a profound impact on calculations for high temperature superconductors. Finally, calculations will be made on the effect of rare fluctuations on the development of turbulence in fluids. Turbulence is an extremely difficult problem to understand and it affects a wide variety of everyday happenings. ***

9419362德意志研究是在理论统计物理的三个领域提出的。(1)研究具有大波动的非平衡过程。其目的是通过使用一种选择大的但不太可能的波动的模拟技术来更好地理解在充分发展的湍流中出现的结构。这些结果应该有助于更好地理解湍流的间歇性。(2)大分子的结构预测。结构和形态的预测在理解材料和生物材料方面很重要，但需要知道系统各个组成部分之间的力。基于蛋白质结构的大量实验数据将被用来系统地确定不同原子或组成亚分子之间相互作用的力场。这一结果将对确定大分子的结构具有重要意义。(3)用统计方法进行量子模拟。由于平均过程中符号的变化，一大类问题很难模拟。这类问题具有根本性和时代性。将研究一种方法，通过用连续变化的相位代替符号的突然变化来极大地加速这一平均过程。考虑到这些阶段的统计数据，改进了计算这些平均值的方法。涉及先进计算技术的理论研究将在处理非常大的随机系统的各种问题上进行。其中一个问题是开发新的方法来更好地确定具有生物重要性的大分子的结构。另一个项目将处理新的算法，以克服一个基本问题，涉及相互作用电子的物理系统的计算。这个问题的解决将对高温超导体的计算产生深远的影响。最后，对稀有波动对流体中湍流发展的影响进行了计算。湍流是一个极难理解的问题，它影响着各种各样的日常事件。***