Density fluctuations of two-dimensional active-passive mixtures

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 tansition 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 P\'eclet number was observed. When phase separation occurs, the fluctuation exponent is an approximate constant of $0.85$.

Activity affects the stability, deformation and breakage dynamics of colloidal architectures

“…In the first stage, the system escapes the potential well and reaches the l 23 -interface for the first time at a particular S-value, which we denote S mech . These S mech -values are counted as n 1-3 (S mech ) which' probability distribution is given by eqn (14). Note that the counts N i-j from eqn ( 12) and ( 13) equal the sum over all S mech -values as N i!j ¼ P S n i!j ðSÞ.…”

“…Indeed, one of the promising directions in material science is to mimic driven biological systems in the form of active (gel) architectures, where active particles provide continuous energy injection. 4 While much research is being done in this area, both on biological materials 3,[5][6][7][8][9] as well as simplified physical systems, [10][11][12][13][14][15] there is a need for wellcontrolled model systems that would allow us to investigate the fundamental physical properties of such driven materials in a systematic way. In this work we investigate activated breakage of self-assembled colloidal architectures relevant for networks and gels.…”