Theory of the quasi-one-dimensional electron gas with strong "on site" interaction

Abstract

A quasi-one-dimensional system with strong attraction between electrons on the same site is analyzed in terms of an equivalent weakly interacting array of Heisenberg-Ising spin chains. The single-chain ground-state properties and elementary excitation spectrum are discussed. It is shown that for certain ranges of the coupling constants, gapless excitations rather widely believed to be present do not in fact exist. Some inadequacies in a recent derivation of a mean-field ordering temperature for interacting spin chains are pointed out, and a new derivation is given. The application of this technique to the quasi-one-dimensional electron system is discussed.