论文标题
颗粒柔软度对活动玻璃动力学的影响
The Influence of Particle Softness on Active Glassy Dynamics
论文作者
论文摘要
主动物质研究越来越适合高密度或玻璃极限。这主要是受活动玻璃材料与传统的被动玻璃物质之间显着相似的启发。有趣的是，在此限制内，最近已经表明，当固有的活性长度尺度（例如持久性长度）等于笼子长度时，活性准标准球的弛豫动力学是非单调的，并且最大程度地增强了活性。该最佳增强作用据称是由于对局部粒子笼的最有效扫描而产生的。在这里，我们证明了这种效果及其物理解释已完全保留在较软的活性球体中。我们对Athermal Active Brownian颗粒（ABP）进行了广泛的模拟，并表明弛豫动力学的非单调变化在不同的柔软度上在质量上保持相似。我们通过将它们与较长的较柔和相互作用电位的范围联系起来来解释定量差异，从而降低了笼子的长度并掩盖了内在的主动运动。此外，我们观察到，只有当持久性长度超过笼子长度时，相对于等效的被动布朗粒子系统，截然不同的定性变化才开始体现出来。总体而言，我们的结果进一步增强了笼子长度的重要性及其与主动玻璃材料背景下相关的活动长度尺度的关系。
Active matter studies are increasingly geared towards the high-density or glassy limit. This is mainly inspired by the remarkable resemblance between active glassy materials and conventional passive glassy matter. Interestingly, within this limit it has recently been shown that the relaxation dynamics of active quasi-hard spheres is non-monotonic and most enhanced by activity when the intrinsic active length scale (e.g., the persistence length) is equal to the cage length, i.e. the length scale of local particle caging. This optimal enhancement effect is claimed to result from the most efficient scanning of local particle cages. Here we demonstrate that this effect and its physical explanation are fully retained for softer active spheres. We perform extensive simulations of athermal active Brownian particles (ABPs) and show that the non-monotonic change of the relaxation dynamics remains qualitatively similar for varying softness. We explain quantitative differences by relating them to the longer range of the softer interaction potential, which decreases the cage length and obscures the intrinsic active motion. Moreover, we observe that only when the persistence length surpasses the cage length, distinct qualitative changes with respect to an equivalent passive Brownian particle system start to manifest themselves. Overall, our results further strengthen the importance of the cage length and its relation to the relevant active length scale in the context of active glassy materials.
