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Center for Nonlinear Studies |
Recently it has been shown that self-propelled agents such as E. coli bacteria will concentrate on one side of a microenvironment when exposed to an array of asymmetrically-shaped gates. Computational studies have verified that this phenomenon occurs in the absence of interparticle interactions; here we present a system of self-propelled particles which exhibits rectification that is strongly dependent on collective interactions. We simulate particles which flock by aligning with their neighbors (c.f. Vicsek et al. 1995) and which additionally experience stiff-spring interparticle repulsion and repulsion mediated by an arrangement of fixed barriers. We show that, by bifurcating the simulation domain with an array of V-shaped gates, the particles preferentially localize to one side of the barrier over time. Moreover, we find that the direction of rectification can be reversed by adjusting the exclusion radii and noise parameters in the equations of motion. These results provide a conceptual basis for isolation and sorting of single- and multi-cellular organisms which move collectively according to flocking-type interaction rules.
Host: Peter Loxley, loxley@lanl.gov