Side information -driven quantum composite control for protecting a\n qubit

We study protection of a qubit that transfer through a decoherence noise by\nquantum control technique. In this work, we assume that the communication\nparticipants have some side information about the qubit. Our aim is to take\nfully advantage of given side information to design a quantum control scheme\nthat makes the output state close to the input state as better as possible.\nEspecially, in this paper, we consider the quantum composite control (QCC)\nstructure, which has shown to capture a better balance between fidelity and\nsuccess probability, i.e., two essential measures for protection. Comparison\nhas been made between our scheme and previous ones. We show there's advantages\nin two aspects. On one hand, when compared with the scheme that has taking\nfully consideration of classical side information but not quantum one, our\nscheme achieves higher fidelity. Inversely, when the scheme with quantum side\ninformation but not classical one is considered, our scheme also has nontrivial\nimprovement.\n