Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
J Chem Phys. 2022 Feb 21;156(7):071102. doi: 10.1063/5.0084213.
We propose a new overarching model for self-propelled particles that flexibly generates a full family of "descendants." The general dynamics introduced in this paper, which we denote as the "parental" active model (PAM), unifies two special cases commonly used to describe active matter, namely, active Brownian particles (ABPs) and active Ornstein-Uhlenbeck particles (AOUPs). We thereby document the existence of a deep and close stochastic relationship between them, resulting in the subtle balance between fluctuations in the magnitude and direction of the self-propulsion velocity. Besides illustrating the relation between these two common models, the PAM can generate additional offsprings, interpolating between ABP and AOUP dynamics, that could provide more suitable models for a large class of living and inanimate active matter systems, possessing characteristic distributions of their self-propulsion velocity. Our general model is evaluated in the presence of a harmonic external confinement. For this reference example, we present a two-state phase diagram that sheds light on the transition in the shape of the positional density distribution from a unimodal Gaussian for AOUPs to a Mexican-hat-like profile for ABPs.
我们提出了一个新的自推进粒子的总体模型，该模型灵活地生成了一整套“后代”。本文引入的一般动力学，我们称之为“亲代”主动模型（PAM），统一了两种常用的描述活性物质的特殊情况，即活性布朗粒子（ABP）和活性奥恩斯坦-乌伦贝克粒子（AOUP）。因此，我们记录了它们之间存在着深刻而密切的随机关系，导致了自推进速度的大小和方向的波动之间的微妙平衡。除了说明这两个常见模型之间的关系外，PAM 还可以生成额外的后代，在 ABP 和 AOUP 动力学之间进行插值，这可以为一大类具有自推进速度特征分布的活的和无生命的活性物质系统提供更合适的模型。我们的一般模型在谐波外部约束下进行了评估。对于这个参考示例，我们提出了一个两态相图，该相图揭示了位置密度分布形状从 AOUP 的单峰高斯分布到 ABP 的墨西哥帽状分布的转变。
