二维各向异性系统中的噪声诱导漂移
Noise-induced drift in two-dimensional anisotropic systems
摘要：
研究了扩散系数随空间变化的系统中粒子的等温布朗动力学。由于系统的不均匀性，即使质点不受任何物理力，其平均位移也不会为零。这种现象被称为“噪声诱导漂移”，并已针对一维系统进行了广泛研究。在这里，我们研究噪声引起的漂移在一个二维各向异性系统，其特征在于一个对称的扩散张量与不平等的对角元素。平均位移矢量的一般表达式推导和呈现为两个矢量的总和，描绘两个不同的漂移效应。第一矢量描述了颗粒在每个正交主扩散方向上向高扩散率侧漂移的趋势。这是一维系统中噪声诱导漂移的著名表达式的推广。第二个矢量表示一种新颖的漂移效应，在一维系统中没有发现，源于主轴方向上的空间旋转。利用Langevin动力学模拟验证了推导表达式的有效性。作为一个具体的例子，我们考虑了两个跨膜蛋白的相对扩散，并证明它们之间的平均距离以每秒几十微米的惊人速度增加。
英文摘要：
We study the isothermal Brownian dynamics of a particle in a system with spatially varying diffusivity. Due to the heterogeneity of the system, the particle's mean displacement does not vanish even if it does not experience any physical force. This phenomenon has been termed "noise-induced drift", and has been extensively studied for one-dimensional systems. Here, we examine the noise-induced drift in a two-dimensional anisotropic system, characterized by a symmetric diffusion tensor with unequal diagonal elements. A general expression for the mean displacement vector is derived and presented as a sum of two vectors, depicting two distinct drifting effects. The first vector describes the tendency of the particle to drift toward the high diffusvity side in each orthogonal principal diffusion direction. This is a generalization of the well-known expression for the noise-induced drift in one-dimensional systems. The second vector represents a novel drifting effect, not found in one-dimensional system, originating from the spatial rotation in the directions of the principal axes. The validity of the derived expressions is verified by using Langevin dynamics simulations. As a specific example, we consider the relative diffusion of two transmembrane proteins, and demonstrate that the average distance between them increases at a surprisingly fast rate of several tens of micrometers per second.
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。
