Eliminating the mean-field shift in multicomponent Bose-Einstein   condensates
  We demonstrate that the nonlinear mean-field shift in a multi-component Bose-Einstein condensate may be eliminated by controlling the two-body interaction coefficients. This modification is achieved by, e.g., suitably engineering the environment of the condensate. We consider as an example the case of a two-component condensate in a tightly confining atom waveguide. Modification of the atom-atom interactions is then achieved by varying independently the transverse wave function of the two components. Eliminating the density dependent phase shift in a high-density atomic beam has important applications in atom interferometry and precision measurement. 
E. V. Goldstein, M. G. Moore, H. Pu and P. Meystre