The derivation of conservation laws for nonlinear Schroedinger equations   with a power type nonlinearity
  For nonlinear Schroedinger equations with a power nonlinearity, a new approach to derive the conservation law of the momentum and the pseudo conformal conservation law is obtained. Since this approach does not contain approximating procedure, the argument is simplified to derive these conservation laws. 
Kazumasa Fujiwara and Hayato Miyazaki
math.AP