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The effective action and the spectrum of collective modes in the antiferromagnetic phase of the three-band repulsive Hubbard model. (English. Russian original) Zbl 0978.82029
J. Math. Sci., New York 100, No. 2, 2147-2155 (2000); translation from Zap. Nauchn. Semin. POMI 245, 216-230 (1997).
Summary: The paper is concerned with the application of path integration (successive integration over “fast”’ and “slow” variables and the Hubbard-Stratonovich transformation) to the antiferromagnetic state in the three-band, two-dimensional repulsive Hubbard model. It is shown that, in the lowest approximation, the model under consideration is equivalent to the half-filled single-band Hubbard model. The effective action for the collective Bose-fields, the critical temperature of the phase transition, and the spectra of excitations are obtained.
82B20 Lattice systems (Ising, dimer, Potts, etc.) and systems on graphs arising in equilibrium statistical mechanics
82B26 Phase transitions (general) in equilibrium statistical mechanics