The 1D Bose Gas with Weakly Repulsive Delta Interaction
  We consider the asymptotic solutions to the Bethe ansatz equations of the integrable model of interacting bosons in the weakly interacting limit. In this limit we establish that the ground state maps to the highest energy state of a strongly-coupled repulsive bosonic pairing model. 
M T Batchelor, X-W Guan, C Dunning and J Links