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Nonequilibrium Relaxation Method

非平衡弛豫法

基本信息

批准号：
15607003
负责人：
ITO Nobuyasu
金额：
$ 2.37万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

One well-established simulation strategy to study the thermal phases and transitions of a given microscopic model system is so-called the equilibrium method, in which one firstly realizes the equilibrium ensemble of a finite system and then extrapolates the results to infinite system. This equilibrium method traces over the standard theory of the thermal statistical mechanics, and over the idea of the thermodynamic limit. Recently, alternative simulation strategy has been developed by the initiative of the head investigator of this research project, which analyzes the nonequilibrium relaxation (NER) process. It is called the NER method. There are some advantages in the NER method over the equilibrium method. The NER method provides simpler analyzing procedure. This implies the less systematic error which is inevitable in the simulation and provides efficient resource usage. Main purpose of this research project is the following: (1) Further development of the NER method. (2) Refinement of the NER method as one standard technique to study material property. (3) Preparation towards analyzer software based on the NER method. During the four years of this project, these three are achieved. Analyzing method of the Kosterlitz-Thouless transition with the NER method is established, and it has turned out that hard-disk melting shows KT transition twice, as an example. Rejection free Monte Carlo method is developed for particle system, which makes simulation more efficient in high density region. An automatic analyzing software named as NER analyzer is designed and partly coded. The NER analyzer analyzes phase and exponent using the NER method by generating specified simulations, simulating and analyzing them, together with making precise log of execution in its database.

平衡法是研究给定微观模型系统的热相和相变的一种成熟的模拟策略，它首先实现有限系统的平衡系综，然后将结果外推到无限系统。这种平衡方法超越了热统计力学的标准理论，超越了热力学极限的思想。最近，在本研究项目负责人的倡议下，开发了一种替代模拟策略，该策略分析了非平衡松弛（NER）过程。它被称为NER方法。与平衡法相比，NER法有一些优点。NER方法提供了更简单的分析过程。这意味着在模拟中不可避免的系统误差较小，并且提供了有效的资源利用。本研究项目的主要目的如下：(1)进一步发展NER方法。(2)改进NER方法，使其成为研究材料性能的一种标准技术。(3)基于NER方法的分析仪软件开发。在这个项目的四年中，实现了这三个目标。建立了用NER方法分析Kosterlitz-Thouless跃迁的方法，并以硬盘熔化为例，分析了两次KT跃迁。提出了粒子系统的无排斥蒙特卡罗方法，使模拟在高密度区域更有效。设计了一种自动分析软件——NER分析仪，并进行了部分编码。NER分析器采用NER方法对相位和指数进行分析，生成指定的仿真，对其进行仿真和分析，并在其数据库中记录精确的执行日志。