Constrained Quantization of Charged Strings in Background B Field and   g-Factors
  The Dirac quantization is performed for the constrained system of the open string with different charges located at both ends in the constant background B field. Noncommutativity reveals to commutators [X, X], [P, P] and also [X,P] at both ends of the string. We consider a dependence on the change of the "cyclotron frequency" of the charged string. The g-factor of the charged string is also calculated in the framework of our formulation. 
Akira Kokado, Gaku Konisi and Takesi Saito