Collective behavior of penetrable self-propelled rods in two dimensions
Collective behavior of penetrable self-propelled rods in two dimensions
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DOI：
10.1103/physreve.88.062314
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发表时间：
2013-12-26
影响因子：
2.4
通讯作者：
Gompper, Gerhard
中科院分区：
文献类型：
--
作者：
Abkenar, Masoud;Marx, Kristian;Gompper, Gerhard
自推进粒子的集体行为是在微观尺度上观察到的游泳者，如精子和细菌，以及蛋白质丝的运动性测定。这类系统的性质既取决于它们的维数，也取决于它们粒子之间的相互作用。我们介绍了一个模型的自推进杆在两个维度上，通过分离移动的伦纳琼斯潜力。由于有限的势垒，棒能够交叉。这个模型使我们能够有效地模拟系统的自推进杆，有效地在二维移动，但偶尔可以逃脱到第三维，以通过对方。我们的准二维自推进粒子描述了一类活跃的系统，其中包括microswimmer靠近墙壁和细丝推进基板上。利用Monte Carlo模拟，我们首先确定了被动棒的各向同性-相变。使用布朗动力学模拟，我们表征集群形成的自推进棒作为一个功能的推进强度，噪音，和能量障碍。与具有无限势垒的棒相反，推进强度的增加不仅有利于对准，而且有效地降低了阻止棒交叉的势垒。因此，我们找到了一个集群窗口，在中等推进强度的最大集群大小。
Collective behavior of self-propelled particles is observed on a microscale for swimmers such as sperm and bacteria as well as for protein filaments in motility assays. The properties of such systems depend both on their dimensionality and the interactions between their particles. We introduce a model for self-propelled rods in two dimensions that interact via a separation-shifted Lennard-Jones potential. Due to the finite potential barrier, the rods are able to cross. This model allows us to efficiently simulate systems of self-propelled rods that effectively move in two dimensions but can occasionally escape to the third dimension in order to pass each other. Our quasi-two-dimensional self-propelled particles describe a class of active systems that encompasses microswimmers close to a wall and filaments propelled on a substrate. Using Monte Carlo simulations, we first determine the isotropic-nematic transition for passive rods. Using Brownian dynamics simulations, we characterize cluster formation of self-propelled rods as a function of propulsion strength, noise, and energy barrier. Contrary to rods with an infinite potential barrier, an increase of the propulsion strength does not only favor alignment but also effectively decreases the potential barrier that prevents crossing of rods. We thus find a clustering window with a maximum cluster size at medium propulsion strengths.