Frictional forces affect the rheology of hard-sphere colloids, at high shear rate. Here we demonstrate, via numerical simulations, that they also affect the dynamics of active Brownian particles and their motility-induced phase separation. Frictional forces increase the angular diffusivity of the particles, in the dilute phase, and prevent colliding particles from resolving their collision by sliding one past to the other. This leads to qualitatively changes of motility-induced phase diagram in the volume-fraction motility plane. While frictionless systems become unstable towards phase separation as the motility increases only if their volume fraction overcomes a threshold, frictional systems become unstable regardless of their volume fraction. These results suggest the possibility of controlling the motility-induced phase diagram by tuning the roughness of the particles.

中文翻译：

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摩擦活性布朗粒子

摩擦力在高剪切速率下影响硬球胶体的流变性。在这里，我们通过数值模拟证明它们还影响活性布朗粒子的动力学及其运动性引起的相分离。在稀相中，摩擦力增加了颗粒的角扩散性，并通过使一个彼此滑过而防止碰撞的颗粒解决其碰撞。这导致了体积分数运动平面中运动诱发的相图的定性变化。尽管无摩擦系统仅在其体积分数超过阈值时才因运动性而变得对相分离不稳定，但摩擦系统却不管其体积分数如何都变得不稳定。