通过转向远离实现的集群运动
Flocking by Turning Away
AI总结：
本研究发现自驱动Janus胶体可通过转向远离相互作用产生集群运动，结合模拟、理论与实验验证了该机制，衔接了对齐与非对齐活性物质类别，为细胞集群运动现象提供了新解释。
摘要：
集群运动（以鸟类为典型范例）是活性智能体的相干集体运动。最初的构想认为，集群运动通过智能体之间的对齐相互作用涌现。本文中，我们报告集群运动也可通过使智能体彼此转向远离的相互作用产生。结合模拟、动力学理论与实验，我们在前端排斥力强于后端的自驱动Janus胶体（两面神胶体）中验证了这一集群运动机制。极性态之所以稳定，是因为粒子在转向远离左侧与右侧邻居之间达成了平衡。与对齐相互作用不同，由转向远离相互作用涌现极性序需要粒子排斥力。在高浓度下，排斥力会产生集群运动的Wigner晶体（维格纳晶体）。尽管排斥力通常会导致活性粒子发生运动诱导相分离，但在此处它与转向远离力矩共同作用产生了集群运动。因此，我们的发现衔接了对齐型与非对齐型活性物质类别。我们的结果有助于调和以下观测现象：细胞尽管通过运动接触抑制彼此转向远离，仍能进行集群运动。总体而言，本研究表明集群运动是一种极强健的现象，即便在取向相互作用看似会阻碍它的情况下也能产生。
英文摘要：
Flocking, as paradigmatically exemplified by birds, is the coherent collective motion of active agents. As originally conceived, flocking emerges through alignment interactions between the agents. Here, we report that flocking can also emerge through interactions that turn agents away from each other. Combining simulations, kinetic theory, and experiments, we demonstrate this mechanism of flocking in self-propelled Janus colloids with stronger repulsion on the front than on the rear. The polar state is stable because particles achieve a compromise between turning away from left and right neighbors. Unlike for alignment interactions, the emergence of polar order from turn-away interactions requires particle repulsion. At high concentration, repulsion produces flocking Wigner crystals. Whereas repulsion often leads to motility-induced phase separation of active particles, here it combines with turn-away torques to produce flocking. Therefore, our findings bridge the classes of aligning and non-aligning active matter. Our results could help to reconcile the observations that cells can flock despite turning away from each other via contact inhibition of locomotion. Overall, our work shows that flocking is a very robust phenomenon that arises even when the orientational interactions would seem to prevent it.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
