Communications in Theoretical Physics ›› 2022, Vol. 74 ›› Issue (7): 075601. doi: 10.1088/1572-9494/ac71fe

• Statistical Physics, Soft Matter and Biophysics • Previous Articles     Next Articles

Density fluctuations of two-dimensional active-passive mixtures

Jian Zhang1,2, Tao Huang3,(), Guoqing Xu1,2, Yong Chen1,2,,()   

  1. 1Center of Soft Matter Physics and Its Applications, Beihang University, Beijing 100191, China
    2School of Physics, Beihang University, Beijing 100191, China
    3Faculty of Science, Kunming University of Science and Technology, Kunming 650093, China
  • Received: 2022-03-01 Revised: 2022-05-19 Accepted: 2022-05-23 Published: 2022-07-01
  • Contact: Yong Chen E-mail:taohonker@gmail.com;ychen@buaa.edu.cn
  • About author: First author contact:Author to whom any correspondence should be addressed.

Abstract:

Dimension-dependent giant density fluctuations are a typical feature of active matter systems. In this work, we study the density fluctuation in two-dimensional mixtures of active and passive particles by Brownian dynamics simulations. The boundary of motility-induced phase separation is determined by the transition from unimodal to bimodal density distribution. A rapid increase of the fluctuation exponent near the boundary of phase separation in the plane of density and Péclet number was observed. When phase separation occurs, the fluctuation exponent is an approximate constant of $0.85.$

Key words: active particle, fluctuation, phase separation