title: Concentration dependence of the collective dynamics of swimming bacteria.
abstract: At concentrations near the maximum allowed by steric repulsion, swimming bacteria form a dynamical state exhibiting extended spatiotemporal coherence. The viscous fluid into which locomotive energy of individual microorganisms is transferred also carries interactions that drive the coherence. The concentration dependence of correlations in the collective state is probed here with a novel technique that herds bacteria into condensed populations of adjustable concentration. For the particular thin-film geometry employed, the correlation lengths vary smoothly and monotonically through the transition from individual to collective behavior.
authors.affiliation: Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Andrey
authors.initials: A
authors.lastname: Sokolov
authors.forename: Igor S
authors.initials: IS
authors.lastname: Aranson
authors.forename: John O
authors.initials: JO
authors.lastname: Kessler
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Goldstein
mesh_terms: D001412:Bacillus subtilis / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D008954:Models, Biological