论文标题

部分可观测时空混沌系统的无模型预测

Active Glassy Dynamics is Unaffected by the Microscopic Details of Self-Propulsion

论文作者

Debets, Vincent E., Janssen, Liesbeth M. C.

论文摘要

近年来,人们对密集的活性材料的兴趣迅速增加,在这种状态下,这种材料与常规的被动玻璃形成物质具有惊人的相似性。对于这样的被动玻璃材料,(至少在三个维度上)已经确定了微观动力学的细节,例如牛顿或布朗尼,不会影响长期的玻璃状行为。在这里,我们通过考虑两个简单且广泛使用的活动粒子模型,即活性Ornstein-uhlenbeck颗粒(AOUP)和活性的Brownian颗粒(ABP),研究在非平衡活动情况下是否仍然存在。特别是,我们试图通过推导热AOUP的模式耦合理论(MCT)来更深入地了解自我推广机制对玻璃动力学的作用,该模式耦合理论(MCT)可以直接与ABP的最近开发的MCT进行比较。两种理论都明确考虑了积极的自由度。我们将AOUP和ABP-MCT方程在两个维度上求解,并证明这两个模型在各种控制参数(包装分数,主动速度和持久性时间)上为中间散射函数提供了几乎相同的结果。我们还通过模拟主动准标准球的多分散混合物来确认不同自我渗透机制之间的理论等效性,从而确定至少对于这些模型系统,自我启动的显微镜细节不会改变主动玻璃行为。

Recent years have seen a rapid increase of interest in dense active materials, which, in the disordered state, share striking similarities with conventional passive glass-forming matter. For such passive glassy materials, it is well established (at least in three dimensions) that the details of the microscopic dynamics, e.g., Newtonian or Brownian, do not influence the long-time glassy behavior. Here we investigate whether this still holds true in the non-equilibrium active case by considering two simple and widely used active particle models, i.e., active Ornstein-Uhlenbeck particles (AOUPs) and active Brownian particles (ABPs). In particular, we seek to gain more insight into the role of the self-propulsion mechanism on the glassy dynamics by deriving a mode-coupling theory (MCT) for thermal AOUPs, which can be directly compared to a recently developed MCT for ABPs. Both theories explicitly take into account the active degrees of freedom. We solve the AOUP- and ABP-MCT equations in two dimensions and demonstrate that both models give almost identical results for the intermediate scattering function over a large variety of control parameters (packing fractions, active speeds, and persistence times). We also confirm this theoretical equivalence between the different self-propulsion mechanisms numerically via simulations of a polydisperse mixture of active quasi-hard spheres, thereby establishing that, at least for these model systems, the microscopic details of self-propulsion do not alter the active glassy behavior.

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