paper

Violation of Luttinger's theorem in strongly correlated electronic systems within a 1/N expansion

arXiv:cond-mat/9906349 · doi:10.1142/S021797929900254X

Abstract

We study the 1/N expansion of a generic, strongly correlated electron model (SU(N) symmetric Hubbard model with and N degrees of freedom per lattice site) in terms of X operators. The leading order of the expansion describes a usual Fermi liquid with renormalized, stable particles. The next-to-leading order violates Luttinger's theorem if a finite convergence radius for the 1/N expansion for a fixed and non-vanishing doping away from half-filling is assumed. We find that the volume enclosed by the Fermi surface, is at large, but finite N's and small dopings larger than at . As a by-product an explicit expression for the electronic self-energy in O(1/N) is given which cannot be obtained by factorization or mode-coupling assumptions but contains rather sophisticated vertex corrections.

revtex, 2 eps figues, to appear on Int. Journ. of Mod. Phys. B

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