Quantum state transfer along a ring with time-reversal asymmetry

Time-reversal symmetry breaking can enhance or suppress the probability of success for quantum state transfer (QST), and remarkably it can be used to implement the directional QST. In this paper we study the QST on a ring with time-reversal asymmetry. We show that the system will behave as a quantum state turnplate under some proper parameters, which may serve as time controlled quantum routers in complex quantum networks. We propose realizing the quantum state turnplate in the coupled resonator optical waveguide by controlling the coupling strength and the phase.