Nonextensive quantum method for itinerant-electron ferromagnetism: The interpolation approximation
نویسنده
چکیده
By using the generalized Femi-Dirac distribution in the interpolation approximation [H. Hasegawa, arXiv:0904.2399], we have discussed magnetic and thermodynamical properties of nonextensive itinerant-electron (metallic) ferromagnets described by the Hubbard model combined with the Hartree-Fock approximation. Magnetic moment, energy, specific heat and spin susceptibility are calculated as functions of the temperature and entropic index q expressing the degree of the nonextensivity: q = 1.0 corresponds to the Boltzmann-Gibbs statistics. A comparison between the results calculated by the interpolation and factorization approximations has been made. It has been pointed out that the factorization approximation yields qualitatively inappropriate results for q < 1.0 and that it overestimates the effect of Stoner excitations for q > 1.0. PACS No.: 05.30.-d, 71.28.+d, 75.10.Lp, 75.40.Cx
منابع مشابه
The interpolation approach to nonextensive quantum systems
Recently it has been shown by the present author [H. Hasegawa, Phys. Rev. E (in press): arXiv:0904.2399] that the interpolation approximation (IA) to the generalized Bose-Einstein and Femi-Dirac distributions yields results in agreement with the exact ones within the O(q − 1) and in highand low-temperature limits, where (q−1) expresses the non-extensivity: the case of q = 1 corresponding to the...
متن کاملNonextensive quantum method for itinerant-electron ferromagnetism: Superstastical approach
Magnetic and thermodynamical properties of itinerant-electron (metallic) ferromagnets described by the Hubbard model have been discussed with the use of the generalized Fermi-Dirac (GFD) distribution for nonextensive quantum systems. We have derived the GFD distribution within the superstatistics, which is equivalent to that obtained by the maximum-entropy method to the Tsallis entropy with the...
متن کاملNonextensive quantum approach to itinerant-electron ferromagnetism: Superstastical method
Magnetic and thermodynamical properties of itinerant-electron (metallic) ferromagnets described by the Hubbard model have been discussed with the use of the generalized Fermi-Dirac (GFD) distribution for nonextensive quantum systems. We have derived the GFD distribution within the superstatistics, which is equivalent to that obtained by the maximum-entropy method to the Tsallis entropy with the...
متن کاملNonextensive quantum method for itinerant-electron ferromagnetism: Fractorization approach
Magnetic and thermodynamical properties of itinerant-electron (metallic) ferromagnets described by the Hubbard model have been discussed with the use of the generalized Fermi-Dirac (GFD) distribution for nonextensive quantum systems. We have derived the GFD distribution within the superstatistics, which is equivalent to that obtained by the maximum-entropy method to the Tsallis entropy with the...
متن کاملGeneralized Bose-Einstein and Fermi-Dirac distributions: The interpolation approximation
Generalized Bose-Einstein and Femi-Dirac distributions in the interpolation approximation (IA) has been shown to yield results in agreement with the exact ones within the O(q − 1) and in highand low-temperature limits [H. Hasegawa, arXiv:0904.2399], where q stands for the entropic index. We have applied the generalized distributions in the IA to typical nonextensive quantum subjects: the black-...
متن کامل