Ground-state correlations in a charged Bose quantum wire

Abstract

We study the ground-state correlations in a charged Bose quantum wire within the self-consistent-field approximation of Singwi, Tosi, Land, and Sjölander. A simple cylindrical model for the quantum wire is used. Static properties (structure factor, pair correlation function, and screened interaction potential), elementary excitation spectra, and ground-state energies are calculated at different boson number densities and wire radii. Our study shows that, in addition to the density of bosons, the wire radius provides an extra control on the strength of the many-body correlations. The correlation effects are found to become increasingly important with decreasing wire radius at a fixed density, and vice versa. The results obtained using the lower-order random-phase approximation are also given. We have compared our results for the screened potential with those for the semiconductor electron quantum wire. It is found that the screened potential for charged bosons is more attractive than that for electrons for r_s < 8, while the two potentials become essentially the same for r_s > 8. Therefore, we conclude that the exchange effects associated with the electron statistics act to oppose the overscreening properties of the charged Bose system and are dominated by the Coulomb correlation effects at low carrier densities corresponding to r_s > 8.