Slow relaxation of randomly packed hard spheres

Abstract

We discover that the apparent weight and the electrical resistance of the randomly packed stainless steel balls exhibit unusually slow relaxation behaviors. It is found experimentally that these relaxations are due to structural change of packing. Simultaneous measurements of the apparent weight and the electrical resistance show correlated time dependence. We have also performed two dimensional molecular dynamics simulations and studied a possible mechanism for the slow relaxation behaviors observed in experiments.