A two-stage approach to relaxation in billiard systems of locally   confined hard spheres
  We consider the three-dimensional dynamics of systems of many interacting hard spheres, each individually confined to a dispersive environment, and show that the macroscopic limit of such systems is characterized by a coefficient of heat conduction whose value reduces to a dimensional formula in the limit of vanishingly small rate of interaction. It is argued that this limit arises from an effective loss of memory. Similarities with the diffusion of a tagged particle in binary mixtures are emphasized. 
Pierre Gaspard, Thomas Gilbert
cond-mat.stat-mech nlin.CD