Effect of confinement on the dynamics of an active suspension of Quincke rotors*

The electrically induced rotation of a sphere in an applied uniform DC field (Quincke effect) has been exploited to engineer particle self-propulsion (Bricard et al, Nature (2013)), by converting rotational to translational motion when the particle is sitting on a surface. In this talk, we discuss the underlying mechanism for self-propulsion in Quincke rollers, allowing us to engineer a novel system consisting of hovering Quincke rotors. We study the characteristic dynamics of these single Quincke “gliders” by quantifying the thresholds for levitation and identifying the ranges for stable stationary electro rotation, periodic rotation and onset of chaotic motion. We further introduce the emergence of unprecedented collective behavior in the multiple hovering particle system and present the corresponding phase diagram of the emergent structures. Our experimental observations offer new insights into the unexplored dynamics of the Quincke system and suggest new paths for further theoretical and experimental development in the dynamics of active systems.