Run-and-tumble is a common but vital strategy that bacteria employ to explore environment suffused with boundaries, as well as to escape from entrapment. We demonstrate that it is crucial to include a commonly neglected thermodynamic effect, through a model that provides analytic explanation of bacterial entrapment in two dimensionless parameters: the ratio of thermal energy to self-propulsion, and an intrinsic shape factor.  We then investigate how run-and-tumble strategy and the resulting dynamical behavior can be sensitively regulated by bacterial dimensions. Our results reveal that the logarithm of the surface residence time for bacteria with constant tumble bias is linearly related to a dimensionless parameter of bacterial intrinsic size characteristics, where a small variation in bacterial dimensions, which is natural in a suspension, reproduces well the large variation in bacterial residence time that is observed in experimental studies. Furthermore, our results predict that the optimal tumble bias corresponding to the maximum surface diffusivity depends strongly on bacterial intrinsic size characteristics, where the same small variation in bacterial dimensions gives rise to a strongly diversified optimal tumble bias.

报告人简介

徐辛亮，海南大学物理与光电工程学院教授，博士生导师。研究领域为统计物理和软凝聚态物理，致力于探索软物质体系丰富的结构性质背后的统计物理基本规律。于2002年在清华大学物理系获得学士学位，2007年在芝加哥大学物理系获得博士学位。在麻省理工学院进行博士后工作后于2014年加入北京计算科学研究中心开展独立工作，于2024年10月加入海南大学物理与光电工程学院，主要研究体系包括复杂流体、活性体系、胶体体系。

邀请人

周海军 研究员