论文标题
通过转向更高密度的区域，主动相分离
Active phase separation by turning toward regions of higher density
论文作者
论文摘要
从分子组件到动物群的活性物质的研究揭示了两种广泛的行为类别：一种趋势，趋势是产生定向秩序和集体运动，而粒子排斥会导致自我捕获和运动诱导的相位分离。在这里，我们报告了第三类行为：产生主动相分离的定向相互作用。结合了自构成的Janus胶体的理论和实验，我们表明后部的排斥力比这些颗粒的前部更强，会产生非晶状体扭矩，从而重新定向粒子向高密度区域的运动。因此，颗粒自行于拥挤的区域，从而导致相位分离。簇保持流体并表现出快速的颗粒更新，与通常由自捕捞引起的堵塞簇相比，界面足够宽，以至于它们跨越整个簇。总体而言，我们的工作确定了基于扭矩的活性流体相位分离的机制，我们的理论预测这些取向相互作用产生了缺乏内部取向顺序的共存阶段。
Studies of active matter, from molecular assemblies to animal groups, have revealed two broad classes of behavior: a tendency to align yields orientational order and collective motion, whereas particle repulsion leads to self-trapping and motility-induced phase separation. Here, we report a third class of behavior: orientational interactions that produce active phase separation. Combining theory and experiments on self-propelled Janus colloids, we show that stronger repulsion on the rear than on the front of these particles produces non-reciprocal torques that reorient particle motion toward high-density regions. Particles thus self-propel toward crowded areas, which leads to phase separation. Clusters remain fluid and exhibit fast particle turnover, in contrast to the jammed clusters that typically arise from self-trapping, and interfaces are sufficiently wide that they span entire clusters. Overall, our work identifies a torque-based mechanism for phase separation in active fluids, and our theory predicts that these orientational interactions yield coexisting phases that lack internal orientational order.
