Article révisé par les pairs
| Résumé : | We briefly recall how the developments of the theory of irreversible processes have led to a dynamical H theorem, requiring only very general assumptions about the initial conditions and a rather simple property of the collision operator in the physical representation. Our aim is to investigate the connection between this theorem and Boltzmann's theory. Instead of the rather complicated case of a dilute gas, we use a simple probabilistic model due to McKean. This enables us to see that the conditions imposed in Boltzmann's formulation on the initial preparation of the system (molecular chaos) are quire restrictive but nevertheless essential for obtaining Boltzmann's H theorem. We also show how, asymptotically, for an aged system, one can recover Boltzmann's results. © 1974. |
