title: Granular entropy: explicit calculations for planar assemblies.
abstract: This paper proposes a new volume function for calculation of the entropy of planar granular assemblies. This function is extracted from the antisymmetric part of a new geometric tensor and is rigorously additive when summed over grains. It leads to the identification of a conveniently small phase space. The utility of the volume function is demonstrated on several case studies, for which we calculate explicitly the mean volume and the volume fluctuations.
authors.affiliation: Polymers and Colloids, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, United Kingdom.
authors.forename: Raphael
authors.initials: R
authors.lastname: Blumenfeld
authors.forename: Sam F
authors.initials: SF
authors.lastname: Edwards