Detailed balance, quantum distribution functions, and equilibrium of mixtures

摘要

We consider systems of nearly free particles (or quasiparticles) interacting by scattering, emission absorption of radiation, or by physical or chemical transformation. The condition of detailed balance yields the appropriate distribution function for each species, the equality of their temperatures, and a relation for their chemical potentials associated with particle transformations. For example, antiparticles coexisting in equilibrium have opposite chemical potentials, and excitations above the Bose-Einstein condensate have zero chemical potential. For mixtures of classical ideal gases, the law of mass action is obtained. (C) 1999 America Association of Physics Teachers. [References: 13]