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Journal of Physics A Mathematical and General

Exact spectrum analysis of a one-dimensional Hubbard model

Philippe Audit

Published Apr 21, 1990• 2 citations
Publisher

Abstract

For a one-dimensional Hubbard model with a half-filled band and one extra hole the single-hole Green function is calculated analytically; the spectrum analysis shows that the N electrons tend to move so as to form identical and consecutive packets to satisfy rules fixed by arithmetical properties of the integer N.
DOI
10.1088/0305-4470/23/8/007

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The diagram technique for the one-band Hubbard model is formulated for the case of moderate to strong Hubbard repulsion.The expansion in powers of the hopping constant is expressed in terms of site cumulants of electron creation and annihilation operators.For Green's function an equation of the Larkin type is derived and solved in a one-loop approximation for the case of two dimensions and nearest-neighbor hopping.With decreasing the electron concentration in addition to the four bands observed at half-filling, a narrow band arises near the Fermi level.The dispersion of the new band, its bandwidth and the variation with filling are close to those of the spin-polaron band in the t-J model.
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