We consider a system of infinitely many hard balls in R^d undergoing Brownian motions and submitted to a smooth pair potential. It is modelized by an infinite-dimensional stochastic differential equation with a local time term. We prove that the set of all equilibrium measures, solution of a detailed balance equation, coincides with the set of canonical Gibbs measures associated to the hard core potential added to the smooth interaction potential.

We consider an infinite system of hard balls in Rd undergoing Brownian motions and submitted to a smooth pair potential. It is modelized by an infinite- dimensional Stochastic Differential Equation with an infinite-dimensional local time term. Existence and uniqueness of a strong solution is proven for such an equation with fixed deterministic initial condition. We also show that Gibbs measures are reversible measures.

We consider a system of infinitely many hard balls in Rd undergoing Brownian motions and submitted to a smooth pair potential. It is modelized by an infinite-dimensional Stochastic Differential Equation with a local time term. We prove that the set of all equilibrium measures, solution of a Detailed Balance Equation, coincides with the set of canonical Gibbs measures associated to the hard core potential added to the smooth interaction potential.

<p> An investigation is carried out to see whether a nonsingular two-nucleon velocity-dependent potential can give similar results as those of a model hard-core potential in the a-state in nuclear-matter. Reasons for failure of some earlier velocity-dependent model potentials to give saturation in nuclear-matter at reasonable densities are examined and a new velocity-dependent potential is proposed which gives results similar to the model hard-core potential. </p> / Thesis / Doctor of Philosophy (PhD)