Fidelity analysis of cyclic three-level system-based quantum routing

A quantum router can guide information from one quantum channel to another; thus, it has an increasingly important role in complex quantum networks. Here, we verify that the quantum router proposed by [L. Zhou et al., Phys. Rev. Lett 111, 103604 (2013)] achieves quantum-state high fidelity. When the transition strengths match [Formula: see text], the fidelity of the atom decreases from the maximum value after a period of time and then rises to a maximum value of 1; if the transition strengths do not match, the fidelity will not be able to reach 1.