Synthesis of stabilizing switched controllers for N-dimensional quantum   angular momentum systems
  This paper provides a class of feedback controllers that guarantee global stability of quantum angular momentum systems. The systems are in general finite dimensions and the stability is around an assigned eigenstate of observables with a specific form. It is realized by employing the control law which was proposed by Mirrahimi & van Handel. The class of stabilizing controllers is parameterized by a switching parameter and we show that the parameter between 0 and 1/N assures the stability, where N is the dimension of the quantum systems. 
Kyosuke Matsumoto, Koji Tsumura and Shinji Hara