Computer Simulations of Phase Transitions

[00:94422 . landau]计算机模拟是获取统计物理学中广泛问题的基本信息和补充传统理论和实验方法的有力工具。这项拨款支持统计系统计算机模拟的广泛计划。作为这项工作的一部分，将开发和改进大规模模拟方法，以研究难以分析处理的系统中的相变。使用的技术包括各种蒙特卡罗和自旋动力学模拟，这些模拟已经非常完善。要检查的模型将与磁性材料（包括具有巨大磁阻的系统）、二元半导体合金、生长薄膜和无序介质有关。其中一些系统包括可能在空间中连续移动并受弹性相互作用影响的粒子，而另一些系统则局限于具有离散近邻相互作用的刚性晶格（包括具有连续自由度的经典自旋）。在许多系统中，有限的几何形状和/或壁的存在是造成与整体不同的行为的原因。平衡系统的静态和动态临界现象将仔细检查，并使用蒙特卡罗和动力学蒙特卡罗方法研究与薄膜生长和超离子扩散有关的简单非平衡模型。在可能的情况下，将结果与分析理论和/或实验进行比较。计算机模拟是获取统计物理中广泛问题的基本信息和补充传统理论和实验方法的有力工具。这笔拨款支持一个广泛的计算机模拟项目。计算技术将得到发展和完善，这些技术将应用于各种物理系统。* * *

0094422LandauComputer simulations are a powerful tool for obtaining fundamental information about wide ranging problems in statistical physics and to complement traditional theoretical and experimental methods. This grant supports a broad program on computer simulations of statistical systems. As part of this effort, large scale simulation methods will be developed and refined for the study of phase transitions in systems which are difficult to treat analytically. Techniques to be used include diverse Monte Carlo and Spin Dynamics simulations which have been exceedingly well refined. Models to be examined will be relevant to magnetic materials (including systems which exhibit colossal magnetoresistance), binary semiconductor alloys, growing films, and disordered media. Several of the systems include particles which may move continuously in space and which are subject to elastic interactions, whereas others will be confined to rigid lattices (including classical spins with continuous degrees of freedom) with discrete near-neighbor interactions. In many of the systems finite geometries and/or the presence of walls are responsible for behavior which is different than that which is found in the bulk. Both static and dynamic critical phenomena for systems in equilibrium will be carefully examined, and simple non-equilibrium models related to film growth and superionic diffusion will be studied using Monte Carlo and Kinetic Monte Carlo methods. Where possible, results will be compared with analytical theory and/or experiment.%%%Computer simulations are a powerful tool for obtaining fundamental information about wide ranging problems in statistical physics and to complement traditional theoretical and experimental methods. This grant supports a broad program on computer simulations. Computational techniques will be developed and refined, and these techniques will be applied to a variety of physics systems. ***