Variational Ground-State Energy of a Bose System. II

Abstract

The variational calculation using a pair-correlation-type trial function is examined for a Bose system interacting through two-body interactions which are sufficiently attractive to give a negative zero-energy scattering length for the two-body scattering. A simple proof is given that in this case the energy-density curve always has a minimum at a certain density with negative energy, and an upper bound on the variation energy is derived.