Bose-Einstein Condensation and Condensation of q-Particles in Equilibrium and Nonequilibrium Thermodynamics

In the setting of the principle of local equilibrium which asserts that the temperature is a function of the energy levels of the system, we exhibit plenty of steady states describing the condensation of free Bosons which are not in thermal equilibrium. The surprising facts are that the condensation can occur both in dimension less than 3 in configuration space, and even in excited energy levels. The investigation relative to non equilibrium suggests a new approach to the condensation, which allows an unified analysis involving also the condensation of q-particles, −1≤q≤1, where q=±1 corresponds to the Bose/Fermi alternative. For such q-particles, the condensation can occur only if 0