arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1706.00784cond-mat.stat-mechcond-mat.softq-bio.QM
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漂移场中的定常扩散:大偏差技术和多尺度分析的比较

Steady diffusion in a drift field: a comparison of large deviation techniques and multiple-scale analysis

Erik Aurell, Stefano Bo

摘要:

具有内部未观测状态的粒子在力场中扩散,通常会显示出有效的对流扩散。漂移速度与在内部状态上平均的迁移率或有效迁移率成比例,而有效扩散具有两项。一个是平衡型的,并满足爱因斯坦关系的有效流动性,而另一个是二次施加的力。在这篇文章中,我们提出了两种新的方法来获得这些结果,一方面使用大偏差技术,另一方面通过多尺度分析,并比较两者。我们考虑两个系统的离散内部状态和连续内部状态。我们表明,辅助方程的多尺度分析也可以在二阶微扰理论中的大偏差理论的生成函数(离散内部状态)或生成功能(连续内部状态)。我们讨论,测量的两个组件的有效扩散给出了一种方法来确定动力学速率从只有第一和第二时刻的位移在稳态。

英文摘要:

A particle with internal unobserved states diffusing in a force field will generally display effective advection-diffusion. The drift velocity is proportional to the mobility averaged over the internal states, or effective mobility, while the effective diffusion has two terms. One is of the equilibrium type and satisfies an Einstein relation with the effective mobility while the other is quadratic in the applied force. In this contribution we present two new methods to obtain these results, on the one hand using large deviation techniques, and on the other by a multiple-scale analysis, and compare the two. We consider both systems with discrete internal states and continuous internal states. We show that the auxiliary equations in the multiple-scale analysis can also be derived in second-order perturbation theory in a large deviation theory of a generating function (discrete internal states) or generating functional (continuous internal states). We discuss that measuring the two components of the effective diffusion give a way to determine kinetic rates from only first and second moments of the displacement in steady state.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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