Bang-Bang refocusing of a qubit exposed to telegraph noise
  We investigate the decoherence effect of telegraph noise on a single qubit, usually provoked by bistable fluctuators. To diminish the dephasing and relaxation impact an effective refocusing scheme (so-called Bang-Bang pulses) is proposed. Detailed numerical as well as analytical random walk analysis allows in particular to evaluate the applicability of non-perfect Bang-Bang pulses. 
H. Gutmann, F.K. Wilhelm, W.M. Kaminsky and S. Lloyd