Objective quantum theory based on the CP(N-1) affine gauge fields
  The ordinary linear quantum theory predicts the quantum correlations at any distance (the universal superposition principle). It creates the decoherence problem since quantum interactions entangle states into non-separable combination. On the other hand the linear quantum theory prevents the existence of the localizable solutions, and after all, leads to the divergences problem in the quantum field theory. In order to overcome these difficulties the non-perturbative nonlinearity originated by the curvature of the compact quantum phase space has been used. 
Peter Leifer