title: Entropy of jammed matter.
abstract: We investigate the nature of randomness in disordered packings of frictional spheres. We calculate the entropy of 3D packings through the force and volume ensemble of jammed matter, a mesoscopic ensemble and numerical simulations using volume fluctuation analysis and graph theoretical methods. Equations of state are obtained relating entropy, volume fraction and compactivity characterizing the different states of jammed matter. At the mesoscopic level the entropy vanishes at random close packing, while the microscopic states contribute to a finite entropy. The entropy of the jammed system reveals that the random loose packings are more disordered than random close packings, allowing for an unambiguous interpretation of both limits.
authors.affiliation: Levich Institute and Physics Department, City College of New York, New York, New York 10031, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Briscoe
authors.forename: Chaoming
authors.initials: C
authors.lastname: Song
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Hernán A
authors.initials: HA
authors.lastname: Makse