Effective diffusion of a tracer in active bath: A path-integral approach
作者机构：Hefei National Research Center for Physical Sciences at the Microscale & Key Laboratory of Precision and Intelligent ChemistryUniversity of Science and Technology of China
出 版 物：《National Science Open》 (国家科学进展)
年 卷 期：2024年第3卷第4期
页 面：29-40页
学科分类：080701[工学-工程热物理] 08[工学] 0807[工学-动力工程及工程热物理]
基 金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0450402) the National Natural Science Foundation of China (32090040 and 22373090)
主 题：active matter nonequilibrium statistical mechanics active bath mean-field theory path integral tracer diffusivity
摘 要：We investigate the effective diffusion of a tracer immersed in an active particle bath consisting of self-propelled particles. Utilising the Dean s method developed for the equilibrium bath and extending it to the nonequilibrium situation, we derive a generalized Langevin equation(GLE) for the tracer particle. The complex interactions between the tracer and bath particles are shown as a memory kernel term and two colored noise terms. To obtain the effective diffusivity of the tracer, we use path integral technique to calculate all necessary correlation functions. Calculations show the effective diffusion decreases with the persistent time of active force, and has rich behavior with the number density of bath particles, depending on different activities. All theoretical results regarding the dependence of such diffusivity on bath parameters have been confirmed by direct computer simulation.
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