Quasi-particles, random fields, and phase transitions in classical statistical mechanics

A unique approach to canonical, grand canonical, and microcanonical ensembles of classical statistical mechanics was formulated. The accessible volume of the phase space of a microcanonical ensemble was related to the canonical partition function of imaginary temperature. Thermodynamic equivalence of inter-atomic interactions and random external fields in a canonical ensemble was proved. Classical statistical mechanics was shown to be equivalent to the theory of nonlinear self-acting fields with temperature-dependent Hamiltonians