Statistical mechanics of composite particles

This paper is concerned with the statistical mechanics of an hydrogenic plasma. Ions are no more randomly fixed, however the present formulation is similar to that of paper (I): starting from the “physical” problem we introduce an “ideal” problem, with an enlarged state space, defined in such a way that its dynamical evolution leads to the dynamical evolution of the “physical” one by means of a projection technique. The fundamental features of the “ideal” problem make it simpler than the physical one: usual commutation relations for the “ideal” creation and annihilation operators and two-particle hamiltonian (instead of an infinite-number-of-particle hamiltonian as in all previous works).