Klymko, Katherine - University of California, Berkeley

Pattern Formation in Driven Systems

We are interested in understanding assembly processes in far-from-equilibrium systems, in particular particle systems under the influence of external driving fields. We have been using theory and computer simulations to study pattern formation in a particular model of driven particles. Our model of interest consists of two types of particles that are pushed in opposite directions by an external AC or DC field and interact with each other through purely repulsive interactions. This model is appealing because it is simple yet provides access to a wide range of patterns in both two and three dimensions which can be accessed by tuning the strength of the external field, the frequency of the field, and the density of the system. For example, this system undergoes a homogeneous to ordered transition as the strength of the external field is increased, characterized by the emergence of dynamic lanes of like particles moving parallel to the field direction. These lanes persist at low field frequencies, but transition to bands perpendicular to the field direction as the frequency increases. Additionally, the bands’ widths can be tuned by adjusting the frequency of the field. We have been working to develop a microscopic understanding of the origins of the different patterns this system supports.