Nonuniversality of density and disorder in jammed sphere packings

We show for the first time that collectively jammed disordered packings of three-dimensional monodisperse frictionless hard spheres can be produced and tuned using a novel numerical protocol with packing density phi as low as 0.6. This is well below the value of 0.64 associated with the maximally random jammed state and entirely unrelated to the ill-defined random loose packing state density. Specifically, collectively jammed packings are generated with a very narrow distribution centered at any density phi over a wide density range phi is an element of (0.6, 0.740 48 ... ) with variable disorder. Our results support the view that there is no universal jamming point that is distinguishable based on the packing density and frequency of occurrence. Our jammed packings are mapped onto a density-order-metric plane, which provides a broader characterization of packings than density alone. Other packing characteristics, such as the pair correlation function, average contact number, and fraction of rattlers are quantified and discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3524489]