论文标题
活性布朗颗粒的均质流体相的异常波动
Anomalous fluctuations in homogeneous fluid phase of active Brownian particles
论文作者
论文摘要
巨型数量波动（GNF）是在具有极性或列表的活性流体中普遍观察到的一种异常。在本文中，我们表明GNF在没有极性的活性布朗颗粒（ABP）的流体相（ABP）中出现。 ABP中的GNF延伸到较大但有限的长度上，这表征了增长的速度相关性。为了抑制不需要的相分离，并允许在大活动中探索无序的流体相，我们将惯性或质量赋予ABP。线性化的流体动力学理论捕获了我们的发现，但仅在定性上捕获了我们的发现。我们在数值上发现了密度相关函数的非平凡缩放关系，线性化理论无法解释。结果表明，即使在没有方向性的情况下，即使在均质流体相位无序中，异常波动的无处不在。
Giant number fluctuations (GNF) are an anomaly universally observed in active fluids with polar or nematic order. In this paper, we show that GNF arise in the fluid phase of active Brownian particles (ABP), where the polar order is absent. GNF in ABP extends over a large but finite length which characterizes the growing velocity correlations. To suppress unwanted phase separation and allow ones to explore the disordered fluid phase at large activities, we impart the inertia, or the mass, to the ABP. A linearized hydrodynamic theory captures our findings, but only qualitatively. We find numerically a nontrivial scaling relation for the density correlation function, which the linearized theory cannot explain. The results suggest ubiquitousness of the anomalous fluctuations even in the disordered homogeneous fluid phase in the absence of the directional order.
