Navigation of Active Microbial Cells

Speaker: Dr Marco Mazza, Loughborough Univesity

Swimming microbial cells have attracted considerable interest from the physics community due to unique interplay of hydrodynamics and nonequilibrium physics. In this talk we will discuss recent results on suspensions of microswimmers. The competition between hydrodynamic interactions and steric forces give rise to a nonmonotonic density dependence of aggregation. We will also discuss the motion of a single motile cell in confinement. Experiments, analytical and numerical calculations indicate that a robust topology of probability flux loops organizes active motion even at the level of a single cell in an isolated habitat. Accounting for the interplay of activity and contact forces, we find that the boundary’s curvature determines the nonequilibrium probability fluxes. We predict a universal relation between fluxes and global geometric properties that is confirmed by experiments.