DERIVATION OF NONLINEAR ONSAGER RELATIONS FROM STATISTICAL MECHANICS

Abstract

The long road that starts from the microscopic equations of motion and ends with the phenomenological equations of the experimenter. is sketched. One type of system leads to nonlinear macroscopic equations, but no reciprocal relations are found. The other type (called diffusive type) leads to a nonlinear Fokker-Planck equation. For low temperature the fluctuations are small and one is left with a set of non linear deterministic equations. They obey the Onsager-Casimir relations.