A billiard model for a gas of particles with rotation

The hard sphere gas is a mathematical model in which several spherical particles collide elastically with each other in a compact Euclidean domain. Using the fact that this system can be modeled as point billiard, its dynamical properties have been investigated extensively, with a great deal of progress towards establishing a central hypothesis, viz., that the system is ergodic. Here we consider the implications of extending the model to include non-spherical particles which have rotational as well as translational components of motion. We show that the point billiard model which forms the basis of the hard sphere gas investigations can be extended to the non-spherical case.