title: Emergence of collective dynamical chirality for achiral active particles.
abstract: Emergence of collective dynamical chirality (CDC) at mesoscopic scales plays a key role in many formation processes of chiral structures in nature, which may also provide possible routines for people to fabricate complex chiral architectures. So far, most of the reported CDCs have been found in systems of active objects with individual structure chirality or/and dynamical chirality, and whether CDC can arise from simple and achiral units is still an attractive mystery. Here, we report a spontaneous formation of CDC in a system of both dynamically and structurally achiral particles motivated by active motion of cells adhered onto a substrate. Active motion, confinement and hydrodynamic interaction are found to be the three key factors. Detailed analysis shows that the system can support abundant collective dynamical behaviors, including rotating droplets, rotating bubbles, CDC oscillations, arrays of collective rotations, and interesting transitions such as chirality transition, structure transition and state reentrance.
authors.affiliation: Department of Chemical Physics & Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China. hzhlj@ustc.edu.cn.
authors.forename: Huijun
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Chemical Physics & Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China. hzhlj@ustc.edu.cn.
authors.forename: Huai
authors.initials: H
authors.lastname: Ding
authors.affiliation: Department of Chemical Physics & Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China. hzhlj@ustc.edu.cn.
authors.forename: Mingfeng
authors.initials: M
authors.lastname: Pu
authors.affiliation: Department of Chemical Physics & Hefei National Laboratory for Physical Sciences at Microscales, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China. hzhlj@ustc.edu.cn.
authors.forename: Zhonghuai
authors.identifier: http://orcid.org/0000-0003-1241-7041
authors.initials: Z
authors.lastname: Hou