Emergence and collapse of coherent motions of self-propelled particles are affected more by particle motions and interactions than by their material or biological details. In the reconstructed systems of biofilaments and molecular motors, several types of collective motion including a global-order pattern emerge due to the alignment interaction. Meanwhile, earlier studies show that the alignment interaction of a binary collision of biofilaments is too weak to form the global order. The multiple collision is revealed to be important to achieve global order, but it is still unclear what kind of multifilament collision is actually involved. In this study, we demonstrate that not only alignment but also crossing of two filaments is essential to produce an effective multiple-particle interaction and the global order. We design the reconstructed system of biofilaments and molecular motors to vary a probability of the crossing of biofilaments on a collision and thus control the effect of volume exclusion. In this system, biofilaments glide along their polar strands on the turf of molecular motors and can align themselves nematically when they collide with each other. Our experiments show the counterintuitive result, in which the global order is achieved only when the crossing is allowed. When the crossing is prohibited, the cluster pattern emerges instead. We also investigate the numerical model in which we can change the strength of the volume exclusion effect and find that the global orientational order and clusters emerge with weak and strong volume exclusion effects, respectively. With those results and simple theory, we conclude that not only alignment but also finite crossing probability are necessary for the effective multiple-particles interaction forming the global order. Additionally, we describe the chiral symmetry breaking of a microtubule motion which causes a rotation of global alignment.

中文翻译：

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滑翔灯丝系统同时提供整体取向顺序和整体运动簇

自推进粒子的相干运动的出现和崩溃受粒子运动和相互作用的影响更大，而不是受其材料或生物学细节的影响。在生物丝和分子马达的重建系统中，由于对齐相互作用，出现了几种类型的集体运动，包括整体运动模式。同时，较早的研究表明，生物丝的二元碰撞的排列相互作用太弱而无法形成整体秩序。多重碰撞对实现全球秩序很重要，但目前尚不清楚实际涉及哪种复丝碰撞。在这项研究中，我们证明，不仅对齐而且两个细丝的交叉对于产生有效的多粒子交互作用和全局顺序至关重要。我们设计了生物丝和分子马达的重建系统，以改变碰撞时生物丝交叉的可能性，从而控制体积排阻的效果。在该系统中，生物丝沿着其极性链在分子马达的草皮上滑动，并且在相互碰撞时可以向列排列。我们的实验显示了违反直觉的结果，其中仅当允许交叉时才实现全局顺序。当禁止穿越时，出现群集模式。我们还研究了可以改变体积排斥效应强度的数值模型，发现整体取向顺序和簇出现时，体积排斥效应弱和强。根据这些结果和简单的理论，我们得出结论，对于形成全局有序的有效多粒子交互作用，不仅需要对齐而且需要有限的穿越概率。另外，我们描述了引起整体排列旋转的微管运动的手性对称性断裂。