Disordered jammed packings of frictionless spheres

At low volume fraction, disordered arrangements of frictionless spheres are found in unjammed states unable to support applied stresses, while at high volume fraction they are found in jammed states with mechanical strength. Here we show, focusing on the hard sphere zero pressure limit, that the transition between unjammed and jammed states does not occur at a single value of the volume fraction, but in a whole volume fraction range. This result is obtained via the direct numerical construction of disordered jammed states with a volume fraction varying between two limits, 0.636 and 0.646. We identify these limits with the random loose packing volume fraction ?rlp and the random close packing volume fraction ?rcp of frictionless spheres, respectively.