Olsen Kristian S, Angheluta Luiza, Flekkøy Eirik G
PoreLab, Department of Physics, University of Oslo, Blindern, 0316 Oslo, Norway.
Soft Matter. 2021 Mar 4;17(8):2151-2157. doi: 10.1039/d0sm01942a.
Disordered media are ubiquitous in systems where self-propelled particles are present, ranging from biological settings to synthetic systems, like in active microfluidic devices. Here we investigate the behavior of active Brownian particles that have an internal energy depot and move through a landscape with a quenched frictional disorder. We consider the cases of very fast internal relaxation processes and the limit of strong disorder. Analytical calculations of the mean-square displacement in the fast-relaxation approximation is shown to agree well with numerically integrated energy depot dynamics and predict normal dispersion for a bounded drag coefficient and anomalous dispersion for power-law dependence of the drag on spatial coordinates. Furthermore, we show that in the strongly disordered limit the self-propulsion speed can, for practical purposes, be considered a fluctuating quantity. Distributions of self-propulsion speeds are investigated numerically for different parameter choices.
无序介质在存在自驱动粒子的系统中无处不在，从生物环境到合成系统，比如在主动式微流控装置中。在这里，我们研究具有内部能量库并在具有猝灭摩擦无序的环境中移动的主动布朗粒子的行为。我们考虑非常快速的内部弛豫过程的情况以及强无序的极限。结果表明，在快速弛豫近似下对均方位移的解析计算与数值积分的能量库动力学结果吻合良好，并且预测对于有界阻力系数为正常扩散，对于阻力对空间坐标的幂律依赖为反常扩散。此外，我们表明在强无序极限下，出于实际目的，自推进速度可被视为一个波动量。针对不同的参数选择，对自推进速度的分布进行了数值研究。
