Marchenko Ivan G, Marchenko Igor I, Aksenova Viktoriia, Łuczka Jerzy, Spiechowicz Jakub
NSC "Kharkiv Institute of Physics and Technology", Kharkiv, 61108, Ukraine.
Institute of Physics, University of Silesia, 41-500, Chorzów, Poland.
Sci Rep. 2025 Mar 25;15(1):10231. doi: 10.1038/s41598-025-94509-w.
Diffusion coefficient usually decreases when friction increases. We analyze the opposite behavior in the paradigmatic system consisting of an inertial Brownian particle moving in a symmetric spatially periodic potential and driven by an unbiased time periodic force. For tailored parameter set in strong dissipation regime the particle spreading can be giantly amplified: if the friction is twice as large then the diffusion grows up to five orders of magnitude. The mechanism lying behind this effect is related to bifurcation of periodic orbits oscillating around the potential maximum and their symmetric displacement towards the adjacent potential minima when the friction coefficient increases. On the other hand, in the weak dissipation regime, where the increase of diffusion vs friction is also observed, the effect is induced by a non-monotonic change of population of the running orbits. However, in this regime the enhancement of diffusion is much smaller.
扩散系数通常会随着摩擦力的增加而减小。我们分析了一个典型系统中的相反行为，该系统由一个在对称空间周期势中运动且受无偏时间周期力驱动的惯性布朗粒子组成。对于强耗散 regime 中的特定参数集，粒子的扩散可以被极大地放大：如果摩擦力增大两倍，那么扩散会增长多达五个数量级。这种效应背后的机制与围绕势垒最大值振荡的周期轨道的分岔以及当摩擦系数增加时它们向相邻势阱的对称位移有关。另一方面，在弱耗散 regime 中，也观察到扩散随摩擦力增加，这种效应是由运行轨道的种群非单调变化引起的。然而，在这个 regime 中，扩散的增强要小得多。
