Anomalous mobility of a driven active particle in a steady laminar flow

Abstract

We study, via extensive numerical simulations, the force-velocity curve of an active particle advected by a steady laminar flow, in the nonlinear response regime. Our model for an active particle relies on a colored noise term that mimics its persistent motion over a time scale $τ_A$. We find that the active particle dynamics shows non-trivial effects, such as negative differential and absolute mobility (NDM and ANM, respectively). We explore the space of the model parameters and compare the observed behaviors with those obtained for a passive particle ($τ_A=0$) advected by the same laminar flow. Our results show that the phenomena of NDM and ANM are quite robust with respect to the details of the considered noise: in particular for finite $τ_A$ a more complex force-velocity relation can be observed.

12 pages, 9 figures, paper submitted for the Special Issue of Journal of Physics: Condensed Matter, "Transport in Narrow Channels", Guest Editors P. Malgaretti, G. Oshanin, J. Talbot