GENERALIZATION OF THE MEAN-FIELD ISING-MODEL WITHIN TSALLIS THERMOSTATISTICS

In this study, the mean-field Ising model, using the Bogolyubov inequa lity which has been obtained in the framework of the generalized stati stical thermodynamics (GST), suitable for non-extensive systems, has b een investigated. Generalized expressions for the mean-field magnetiza tion and free energy have been established. These new results have bee n verified by the fact that they transform to the well-known Boltzmann -Gibbs results in the q-->1 limiting case. For the index q which chara cterizes the fractal structure of the magnetic system, an interval has been established where the generalized mean-field free energy has a m inimum and mean-field magnetization has a corresponding finite value. The interval of q is consistent with paramagnetic free spin systems.