运用CTRW-Metropolis模型数值研究亚稳势中粒子逃逸问题  

Escape from Metastable Potentials in a CTRW-Metropolis Model

作　　者：林方[1] 包景东[1] 

机构地区：[1]北京师范大学物理系,北京100875

出　　处：《计算物理》2009年第3期461-466,共6页Chinese Journal of Computational Physics

摘　　要：基于连续时间随机行走(CTRW)理论,实现反常扩散条件下对跳跃步长和等待时间分布函数的抽样,改进Metropolis抽样判定方法以适用于存在非线性势的情况.数值研究布朗粒子在亚稳势下的逃逸速率.结果显示,稳定逃逸速率γst随反常指数α非单调变化,在超扩散条件下存在极大值和位垒相消现象.A numerical method based on continuous time random walk （CTRW） theory is developed for anomalous diffusion. Probability density functions for both jump distance and residence time in CTRW model are determined. Metropolis sampling method is improved in the case of nonlinear potentials. Escape rate in metastable potential is investigated. It shows that stationary escape rate is non-monotonic as anomalous index α increases. A maximum of escape rate exists in the case of super-diffusion and a cancellation phenomenon in barrier region is found.

关 键 词：连续时间随机行走 Metropolis抽样 亚稳势 逃逸速率 位垒相消 

分 类 号：O414.2[理学—理论物理]