Brownian particles far from equilibrium
Brownian particles far from equilibrium
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DOI：
10.1007/s100510051104
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发表时间：
2000-05-01
影响因子：
1.6
通讯作者：
Schweitzer, F
中科院分区：
文献类型：
--
作者：
Erdmann, U;Ebeling, W;Schweitzer, F
本文研究了布朗粒子模型，它是通过一个非线性摩擦函数被能量抽运的，并讨论了不同的类型。通过考虑布朗粒子的内部能量库，导出了一个合适的非线性、速度依赖的摩擦函数的表达式。在这种情况下，摩擦函数描述了在小速度范围内的能量泵送，而在大速度范围内，达到了耗散摩擦的已知极限。为了研究附加能量的影响，我们讨论了不同情况下的速度分布函数。给出了相应的二维Fokker-Planck方程的解析解，并与计算机模拟结果进行了比较。与被动布朗运动的情况不同，我们发现了一些新的动力学特征，如在四维相空间中形成极限环，大的均方位移随能量供应呈二次方增加，或具有火山口状形式的非平衡速度分布。此外，我们指出一些概括和可能的应用模型。
We study a model of Brownian particles which are pumped with energy by means of a non-linear friction function, for which different types are discussed. A suitable expression for a non-linear, velocity-dependent friction function is derived by considering an internal energy depot of the Brownian particles. In this case, the friction function describes the pumping of energy in the range of small velocities, while in the range of large velocities the known limit of dissipative friction is reached. In order to investigate the influence of additional energy supply, we discuss the velocity distribution function for different cases. Analytical solutions of the corresponding Fokker-Planck equation in 2d are presented and compared with computer simulations. Different to the case of passive Brownian motion, we find several new features of the dynamics, such as the formation of limit cycles in the four-dimensional phase-space, a large mean squared displacement which increases quadratically with the energy supply, or non-equilibrium velocity distributions with crater-like form. Further, we point to some generalizations and possible applications of the model.