Many active biological particles, such as swimming microorganisms or motor-proteins, do work on their environment by going though a periodic sequence of shapes. Interactions between particles can lead to the phase-synchronization of their duty cycles. Here we consider collective dynamics in a suspension of such active particles coupled through hydrodynamics. We demonstrate that the emergent non-equilibrium states feature stationary patterned flows and robust unidirectional pumping states under confinement. Moreover the phase-synchronized state of the suspension exhibits spatially robust chimera patterns in which synchronized and phase-isotropic regions coexist within the same system. These findings demonstrate a new route to pattern formation and could guide the design of new active materials.
Self-organized flows break morphological symmetry in active/passive systems
Institute of Scientific Computing, Technische Universität Dresden（德累斯顿工业大学科学计算研究所）；Center for Systems Biology Dresden（德累斯顿系统生物学中心）；Cluster of Excellence, Physics of Life, Technische Universität Dresden（德累斯顿大学生命物理卓越集群）
Self-Organized Velocity Pulses of Dense Colloidal Suspensions in Microchannel Flow
本文对压力驱动的微通道中稠密胶体悬浮液的二维流动进行了数值研究。胶体被模拟为弹性和摩擦球悬浮在牛顿流体中，我们模拟使用多粒子碰撞动力学的方法。该模型再现了周期性的速度和密度脉冲序列，在微通道中向上游行进，这是在L。Isa等人[Phys. Rev. Lett. 102，058302（2009）]。我们发现，胶体壁摩擦和合力链是至关重要的这些脉冲的形成。随着胶体密度的增加，首先出现孤立子阻塞，在中等密度下形成周期脉冲串，在高密度下形成不稳定的孤立子脉冲。我们制定了一个唯象的连续模型，并展示了如何这些时空流和密度分布可以被理解为同宿和周期轨道的行波方程。
Spontaneous oscillations and geometric cutoff in confined bacterial swarms
Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences (UCAS)（中国科学院大学材料科学与光电技术学院物质科学与光电工程中心）；Department of Physics, Hong Kong Baptist University（香港浸会大学物理系）；Center for Interdisciplinary Studies, Westlake University（西湖大学交叉研究中心）
Elasticity-Driven Periodic Polarization Patterns in Confined Chiral Ferroelectric Nematic Fluid
Jožef Stefan Institute（约瑟夫·斯特凡研究所）；Faculty of Mathematics and Physics, University of Ljubljana（卢布尔雅那大学数学与物理学院）；CENN Nanocenter（CENN纳米中心）；Department of Physics, Faculty of Science and Technology, University of the Basque Country UPV/EHU（巴斯克国立大学理学院物理系）；School of Chemistry, University of Leeds（利兹大学化学学院）；School of Physics and Astronomy, University of Leeds（利兹大学物理与天文学院）
Universitat de Barcelona（巴塞罗那大学）；Institute of Nanoscience and Nanotechnology, IN2UB, Universitat de Barcelona（巴塞罗那大学纳米科学与技术研究所）；Centro Brasileiro de Pesquisas Físicas（巴西物理研究中心）；Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa（里斯本大学理学院理论与计算物理中心）；Departamento de Física, Faculdade de Ciências, Universidade de Lisboa（里斯本大学理学院物理系）；Institute for Bioengineering of Catalonia, The Barcelona Institute for Science and Technology（加泰罗尼亚生物工程学院，巴塞罗那科学技术研究院）
