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Physical picture of the gapped excitation spectrum of the one-dimensional Hubbard model

D. Braak·N. Andrei
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Abstract

A simple picture for the spectrum of the one-dimensional Hubbard model is presented using a classification of the eigenstates based on an intuitive bound-state Bethe-Ansatz approach. This approach allows us to prove a "string hypothesis" for complex momenta and derive an exact formulation of the Bethe-Ansatz equations including all states. Among other things we show that all gapped eigenstates have the Bethe-Ansatz form, contrary to assertions in the literature. The simplest excitations in the upper Hubbard band are computed: we find an unusual dispersion close to half-filling.

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D. Braak, N. Andrei. 1998-09-22. Physical picture of the gapped excitation spectrum of the one-dimensional Hubbard model. https://doi.org/10.1016/s0550-3213(98)00811-6

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