Motile Colloids with Tunable Random Walk: Individual Dynamics and Collective Behavior"

Active particles such as swimming bacteria or self-propelled colloids spontaneously self-organize into large-scale dynamic structures. The emergence of the collective states from the motility pattern of the individual particles, typically a random walk, is yet to be probed in a well-defined synthetic system. Recently, the PIs created a motile colloid that reproduces run-and-tumble and Levy walks by exploiting the Quincke effect to achieve controlled sequences of repeated particle runs and random reorientations. Preliminary work by the PIs found that population of these random walkers exhibit behaviors reminiscent of bacterial suspensions such as dynamic clusters and mesoscale turbulent-like flows. However, the complete phase diagram and the mechanisms driving the collective states. To fill this void, we propose a combined theoretical and experimental study.