Technique of quantum state transfer for a double Lambda atomic beam
  The transfer technique of quantum states from light to collective atomic excitations in a double $\Lambda$ type system is extended to matter waves in this paper, as a novel scheme towards making a continuous atom laser. The intensity of the output matter waves is found to be determined by the initial relative phase of the two independent coherent probe lights, which may indicate an interesting method for the measurement of initial relative phase of two independent light sources. 
Xiong-Jun Liu, Hui Jing, Xiao-Ting Zhou and Mo-Lin Ge