Composite control for protecting two nonorthogonal qubit states against decoherence
Ya Cao, Guojing Tian, Zhichao Zhang, Ying‐Hui Yang, Qiaoyan Wen, Fei Gao · Physical Review A · 2017
Quantum feedback control (QFBC) and quantum feedforward control (QFFC) are two of the major techniques for protecting two nonorthogonal qubit states against decoherence. In this paper, we propose a quantum composite control scheme for protecting such states, where QFBC and QFFC are combined. Note that the combination is deliberately devised, other than simply one plus one (i.e., the trivial combination). We show the performance of our scheme is better than that of both the previous control schemes and the trivially combined one for most states and noises in the sense that, for given success probability, our scheme can achieve the biggest fidelity, and for given fidelity, our scheme has the biggest success probability. Furthermore, our scheme can be experimentally implemented with current technologies.