Fazli Zahra, Naji Ali
School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
Phys Rev E. 2021 Feb;103(2-1):022601. doi: 10.1103/PhysRevE.103.022601.
We study steady-state properties of active, nonchiral and chiral Brownian particles with polar alignment and steric interactions confined within a ring-shaped confinement (annulus) in two dimensions. Exploring possible interplays between polar interparticle alignment, geometric confinement and the surface curvature, being incorporated here on minimal levels, we report a surface-population reversal effect, whereby active particles migrate from the outer concave boundary of the annulus to accumulate on its inner convex boundary. This contrasts the conventional picture, implying stronger accumulation of active particles on concave boundaries relative to the convex ones. The population reversal is caused by both particle alignment and surface curvature, disappearing when either of these factors is absent. We explore the ensuing consequences for the chirality-induced current and swim pressure of active particles and analyze possible roles of system parameters, such as the mean number density of particles and particle self-propulsion, chirality, and alignment strengths.
我们研究了二维环形约束（环面）内具有极性排列和空间相互作用的活性、非手性和手性布朗粒子的稳态性质。通过在最小程度上考虑极性粒子间排列、几何约束和表面曲率之间可能的相互作用，我们报告了一种表面种群反转效应，即活性粒子从环面的外凹边界迁移，聚集在其内凸边界上。这与传统观点相反，传统观点认为活性粒子在凹边界上的聚集相对于凸边界更强。种群反转是由粒子排列和表面曲率共同引起的，当这两个因素中的任何一个不存在时，这种效应就会消失。我们探讨了由此对活性粒子的手性诱导电流和游动压力产生的后果，并分析了系统参数（如粒子的平均数密度、粒子的自推进、手性和排列强度）可能发挥的作用。
