Pattern formation in nonreciprocal quorum-sensing active particles

报告题目：Pattern formation in nonreciprocal quorum-sensing active particles

报告人：段煜博士，德国马普所动力学和自组织研究所

报告时间：2024-11-06，下午14:00

报告地点：物理科技楼245

报告摘要：Over the past years, the generation of interactions breaking action-reaction symmetry has emerged as new paradigm for active matter. Such nonreciprocal interactions have in particular been argued to constitute a generic route for the emergence of steady states breaking time reversal symmetry. The generalization of the Cahn-Hilliard theory of phase separation to nonreciprocal mixtures predicts, for example, the emergence of traveling states when intra-species attraction leads to demixing while chasing inter-species interactions are present. Here, we study a minimal model of active phase separation involving two species of particles regulating their self-propulsion speed via quorum-sensing rules. Combining simulations of the microscopic model and linear stability analysis of the associated coarse-grained field theory, we identify a mechanism for dynamical pattern formation that does not rely on the standard route of intra-species effective attractive interactions. Instead, our results reveal a highly dynamical phase of chasing bands induced only by the combined effects of self-propulsion and nonreciprocity in the inter-species couplings. Turning on self-attraction, we find that the system may phase separate into a macroscopic domain of such chaotic chasing bands coexisting with a dilute gas. We show that the chaotic dynamics of bands at the interfaces of this phase-separated phase results in anomalously slow coarsening.

报告人简介：Yu Duan obtained his Ph. D. degree from Nanjing university in 2021 supervised by Prof. Yuqiang Ma. After working in Soochow university as a research assistant for a short period, he joined the Living Matter Physics Department of Max Planck Institute for Dynamics and Self-organization in 2022 and worked as a postdoc until now. He mainly uses simulations and theory to study the collective behavior of active matter. Currently, he is interested in understanding the emergent phase behavior in nonreciprocal active system.