Title: Structure and dynamics of a vibrated granular bead-chain

Author (Talk): Kevin Safford, Clark University

Abstract:

\\documentclass{article} \\begin{document} \\title{Structure and dynamics of a vibrated granular bead-chain} \\authors{Kevin Safford and Arshad Kudrolli (Clark University), Mehran Kardar (MIT), Yacov Kantor (Tel Aviv University)} We investigate the dynamics of a vibrated granular bead-chain with experiments and numerical simulations of random-walk models of polymers. Experiments are conducted with a chain composed of hollow 3~mm steel beads connected by flexible links confined to move on a 30~cm diameter rough circular bed and observations made with digital imaging. We analyze the radius of gyration $R_g$, the structure factor of the chain configurations, and the diffusion of the center of mass. We find that the radius of gyration and the structure factor scale with the exponent $/nu$ very near 3/4, consistent with the two dimensional self avoiding random walk model. The diffusion of the beaded chain is observed to scale inversely as the length of the chain consistent with Rouse model of polymers. We also observe confinement effects in the scaling of $R_g$ as the polymer size increases relative to the size of the container. We perform simulations of non-self avoiding walks confined to the same sized domain and find good agreement with experiment. \\end{document}