Behavior of Large Random Systems

9419362德意志研究在理论统计物理的三个领域提出。(1)具有大波动的非平衡过程的研究。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完全发展的湍流中出现的结构。这些结果将有助于我们更好地理解湍流的间断性。(2)大分子结构预测。结构和形态的预测对于理解材料和生物材料是很重要的，但需要知道系统的各个构建块之间的力。蛋白质结构的大型实验数据库将用于系统地确定作用于不同原子或组成亚分子之间的力场。这些结果对于确定大分子的结构具有重要意义。(3)利用统计方法进行量子模拟。由于平均过程中符号的变化，大量的问题难以模拟。这类问题具有根本性和现实性。我们将研究一种方法，用连续变化的相位代替符号的突然变化，从而大大加快这一平均过程。考虑这些阶段的统计数据，可以改进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重要的生物大分子的结构。另一个项目将处理新的算法，以解决涉及相互作用电子物理系统计算的基本问题。这一问题的解决将对高温超导体的计算产生深远的影响。最后，将计算稀有波动对流体湍流发展的影响。湍流是一个极其难以理解的问题，它影响着各种各样的日常事件。＊＊＊

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. ***