By using the Bogoliubov perturbation theory in combination with variational methods, we derive an expression for the ground-state energy for a one-dimensional neutral system containing a large number (N) of locally interacting ‘‘charged’’ bosons in one dimension. When only ‘‘Coulomb-like’’ interactions are considered, the employment of Dirichlet boundary conditions leads to a physically sensible bound state, while using periodic boundary conditions does not. As far as the large-N dependence is concerned, our results agree with those proposed recently, but our derived expression produces a better value for the ground-state energy.

• Received 27 February 1992

DOI:https://doi.org/10.1103/PhysRevA.46.2271