布朗马达的非均匀高斯跃迁模型  

A nonuniform ratchet model with Gauss-transition rates for Brownian motor

作　　者：李微[1] 赵同军[1] 郭鸿涌[2] 纪青[1] 展永[1] 

机构地区：[1]河北工业大学理学院,天津300130 [2]河北工业大学电气工程学院,天津300130

出　　处：《物理学报》2004年第11期3684-3689,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 3 75 0 16);河北省自然科学基金 (批准号 :A2 0 0 40 0 0 0 0 5和B2 0 0 1113 )资助的课题~~

摘　　要：提出了布朗马达的非均匀高斯跃迁理论 ,用布朗粒子在多态之间的跃迁模型描述分子马达的定向运动 .假定跃迁速率与位置有关 ,且在跃迁点附近具有高斯函数形式 ,将布朗粒子在x处的概率密度Pm(x ,t)在跃迁点附近展开 ,可以进行任意阶的近似计算 .这一理论涵盖了以往的定点跃迁模型和均匀跃迁模型 .作为具体例子 ,研究了系统在两态之间的跃迁问题 .假定在一个周期内有两个跃迁点 ,讨论了布朗粒子定向运动产生的概率流随温度。A nonuniform ratchet model with Gauss-transition rates is proposed to discuss the directional motion of Brownian particles in an asymmetrical periodic potential. It is assumed that the particles experience several internal states in a single mechanical-chemical circle. In this model, the transition rates between different states are position-dependent, which have the form of Gaussian function. For any internal states, the probability distribution as a function of time and position may be expanded near the transition points to any rank if necessary. Finally, the focus of our study is concentrated on a two-state model, in which we choose (M, K)=(2, 2) and calculate the average current as a function of the transition width, temperature and transition rate. It is revealed that the transition width influences the current greatly.

关 键 词：跃迁 布朗粒子 任意阶 非均匀 概率密度 变化关系 近似计算 高斯 定向运动 定点 

分 类 号：O552[理学—热学与物质分子运动论] G633[理学—物理]