An equilibrium thermostatistics of a nonextensive finite system: Canonical distribution and entropy

A simple model is presented to illustrate the equilibrium thermostatistics of a nonentensive finite system. Interaction between the finite system and the reservoir is taken into account as a nonextensive term λH1H2 in the expression of total energy (H1 and H2 are the energy of the finite system and the reservoir respectively, λ is nonadditivity parameter). In the present paper, a case with harmonic reservoir potential is considered. Energy probability distribution, average energy, heat capacity and entropy function for energy distribution are derived in different finite systems including those with constant density of state in energy, the ideal gas and the phonon gas.