A case concerning the improved transition probability
  As is well known, the existed perturbation theory can be applied to calculations of energy, state and transition probability in many quantum systems. However, there are different paths and methods to improve its calculation precision and efficiency in our view. According to an improved scheme of perturbation theory proposed by [An Min Wang, quant-ph/0611217], we reconsider the transition probability and perturbed energy for a Hydrogen atom in a constant magnetic field. We find the results obtained by using Wang's scheme are indeed more satisfying in the calculation precision and efficiency. Therefore, Wang's scheme can be thought of as a powerful tool in the perturbation calculation of quantum systems. 
Jian Tang and An Min Wang