Laboratory of Quantum Information Technology, ICMP and SPTE, South China Normal University, 510006 Guangzhou, China.
J Chem Phys. 2010 Mar 7;132(9):094504. doi: 10.1063/1.3327842.
Transport of the Brownian particles driven by Lévy flights coexisting with subdiffusion in asymmetric periodic potentials is investigated in the absence of any external driving forces. Using the Langevin-type dynamics with subordination techniques, we obtain the group velocity which can measure the transport. It is found that the group velocity increases monotonically with the subdiffusive index and there exists an optimal value of the Lévy index at which the group velocity takes its maximal value. There is a threshold value of the subdiffusive index below which the ratchet effects will disappear. The nonthermal character of the Lévy flights and the asymmetry of the potential are necessary to obtain the directed transport. Some peculiar phenomena induced by the competition between Lévy flights and subdiffusion are also observed. The pseudonormal diffusion will appear on the level of the median.
在没有外部驱动力的情况下,研究了布朗粒子在非对称周期势中由 Lévy 飞行和亚扩散共同驱动的输运。使用次扩散的次隶属技术的 Langevin 型动力学,我们得到了可以测量输运的群速度。发现群速度随着亚扩散指数单调增加,并且在 Lévy 指数存在最佳值,此时群速度取最大值。亚扩散指数存在一个阈值,低于该阈值,棘轮效应将消失。 Lévy 飞行的非热特性和势的不对称性是获得定向输运的必要条件。还观察到 Lévy 飞行和亚扩散之间竞争引起的一些特殊现象。中值处会出现拟正态扩散。