ABSTRACT
In this chapter, a more general approach is developed in terms of the partition function Z. It focuses mainly on systems of localized and, in principle, distinguishable particles such as spins on fixed lattice sites in solids. The various ensembles introduced into statistical physics correspond to particular physical situations of interest. Mean values may readily be obtained with the canonical distribution. The chapter describes the microcanonical, canonical, and grand canonical ensembles. In addition to thermodynamic systems, the Boltzmann and Gibbs equations for the entropy can be applied to other systems which involve statistical descriptions. The grand canonical ensemble involves baths for which the temperature and chemical potential are specified.
