Feedback control on geometric phase in dissipative two-level systems
  The effect of feedback on a two-level dissipative system is studied in this paper. The results show that it is possible to control the phase in the open system even if its state can not be manipulated from an arbitrary initial one to an arbitrary final one. The dependence of the geometric phase on the control parameters is calculated and discussed. 
H. Y. Sun, P. L. Shu, C. Li, X. X. Yi