Flocks, Flow and Fluctuations in Inanimate Matter : Simulations and Theory

Abstract

In this thesis we study a novel soft-matter system that imitates motility. Our system consists of a few asymmetrically tapered brass rods and aluminium beads which are confined between two vertically shaking plates. The rods are motile due to interplay of their the fore-aft asymmetric shape, vibrational energy input, and the mechanics of contact with the bounding surfaces. Experiments done by our col- laborators revealed that the system undergoes a phase transition from a disordered state to an ordered coherently moving flock above a critical bead concentration. We have used time-driven numerical simulations and analytical theory to understand the physics underlying the phenomenon.