High-Density Expansion for the Spinless Fermion Model III : Green-Functions

• The single-particle electron Green's function and the charge-fluctuation Green's function for the spin-polarized fermion lattice gas are calculated within the framework of the high-density expansion up to the first order in 1/z. Violation of some conditions of consistency of diagrammatic perturbation expansion approximation schemes are discussed. Relations between the Green's functions and corresponding approximate free energy are established. Two kinds of approximations for Green's functions for the charge ordered phase are constructed and applied to determine the band structure of the spinless fermion model. The Green's functions for the nonordered phase are used to study the phase diagram of the model for finite temperatures and arbitrary band filling. 

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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