报告主题：活性手性和手性活性液晶

主讲人：张锐助理教授（香港科技大学）

主持人：高永祥

时 间：2024年10月17日周四14：00

地 点：致知楼706

嘉宾简介：

Dr. ZHANG Rui is currently an Assistant Professor of Physics at the Hong Kong University of Science and Technology (HKUST) and an affiliate member at the WPI Institute, Hiroshima University. Before joining HKUST, he was a Distinguished Research Associate in the Pritzker School of Engineering at the University of Chicago. Prior to that, he was at the Levich Institute of Physio-Chemical Hydrodynamics at City College of New York. He obtained his B.S. in Physics from Fudan University. Dr Zhang is a computational soft matter physicist specialized in active matter, liquid crystals, and nanofluidics. He has published as first or corresponding author in many top journals, including Nature Materials, Nature Reviews Materials, PRL, PNAS, Nature Communications, Science Advances among others. He is currently serving on the Executive Committee for the Physical Society of Hong Kong.

报告摘要：

Active liquid crystal (LCs) is a paradigmatic active matter system, in which topological defects become self-propelled and spontaneous flows are developed. There is a recent interest in chiral active matter. There are, however, two types of chirality in active LCs. For active cholesteric LC having structural chirality, we show by theory that +1/2 defects in a quasi-two-dimensional (2D) active chiral nematic can break the symmetry by exhibiting circular motion. We further conduct hydrodynamic simulations of thin spherical-shell and thin cylindrical-shell systems to test our prediction. In the spherical-shell confinement, the four emerged +1/2 disclinations exhibit rich dynamics as a function of activity and chirality. In the thin cylindrical-shell system, +1/2 defect exhibits a helical motion with its pitch varying with the chirality. For active LC with dynamic chiral stresses, we focus on 2D systems and investigate how flow-aligning parameter and confinement and boundary conditions dictate the dynamics of active defects and the edge flow. As such, we have revealed a new symmetry-breaking scenario in chiral active matter, clarified different types of chirality, and provided new insights into defect dynamics in active matter.