Understanding complex matter from simple packing models

By pouring equal balls into a container one obtains disordered packings with fascinating properties which might shed light on several elusive properties of complex materials such as amorphous metals or colloids. In any real experiment with equal-sized spheres one cannot reach packing fractions (fraction of volume occupied by the spheres respect to the total volume, ρ) below the Random Loose Packing limit (RLP, ρ ~ 0.555) or above the Random Close Packing limit (RCP, ρ ~ 0.645) unless order is externally induced. What is happening at these two limits is an open unanswered question. In this paper we address this question by combining statistical geometry and statistical mechanics methods. Evidences of phase transitions occurring at the RLP and RCP limits are reported.