We propose a quantum state protection scheme via quantum feedforward control combined with environment-assisted measurement to protect arbitrary unknown initial states from the finite-temperature thermal noise(FTTN).T...We propose a quantum state protection scheme via quantum feedforward control combined with environment-assisted measurement to protect arbitrary unknown initial states from the finite-temperature thermal noise(FTTN).The main strategy is to transfer the quantum system to a noise-robust state by weak measurement and feedforward control before the noise channel.Then we apply the environment-assisted measurement on the noise channel to select our desired damped states that are invertible to the initial state.After the noise channel,the reversal operations are applied to restore the initial state.We consider the protection of a single-qubit system,derive the analytical expressions of the success probability and the fidelity,and analyze the influence of key parameters on the performance of the proposed scheme.Unlike previous studies,there is no trade-off between the fidelity and the success probability in the proposed scheme;hence one could maximize them separately.Simulation results show that the proposed scheme can greatly improve the fidelity of the quantum state with a certain success probability.Moreover,the proposed scheme is successfully applied to improving the fidelity of controlled quantum teleportation through two independent FTTN channels from the perspective of protecting the shared entanglement.展开更多
Quantum teleportation as the key strategy for quantum communication requires pure maximally shared entangled states among quantum nodes.In practice,quantum decoherence drastically degrades the shared entanglement duri...Quantum teleportation as the key strategy for quantum communication requires pure maximally shared entangled states among quantum nodes.In practice,quantum decoherence drastically degrades the shared entanglement during entanglement distribution,which is a serious challenge for the development of quantum networks.However,most of the decoherence control strategies proposed thus far are either resource-intensive or time-consuming.To overcome this obstacle,we enable noise-resistant teleportation through a noisy channel with a limited number of qubits and without applying time-consuming weak measurements.We apply a quantum gate control unit consisting of a controlled NOT gate and a rotation gate after the original teleportation protocol is accomplished.Furthermore,we demonstrate that a teleportation fidelity of unity is attainable when environment-assisted measurement is added to the proposed teleportation protocol via quantum gates.Moreover,we present an entanglement distribution process by employing the designed quantum gate control unit followed by the deterministic standard teleportation protocol to improve teleportation fidelity by establishing improved shared entanglement.Our performance analysis indicates that the proposed teleportation schemes offer a competitive fidelity and success probability compared with the conventional schemes and a recent weak measurement-based teleportation protocol.展开更多
基金the National Natural Science Foundation of China(Grant No.61973290)a Program from Ministry of Science and Technology of China(Grant No.QN2022200007L)。
文摘We propose a quantum state protection scheme via quantum feedforward control combined with environment-assisted measurement to protect arbitrary unknown initial states from the finite-temperature thermal noise(FTTN).The main strategy is to transfer the quantum system to a noise-robust state by weak measurement and feedforward control before the noise channel.Then we apply the environment-assisted measurement on the noise channel to select our desired damped states that are invertible to the initial state.After the noise channel,the reversal operations are applied to restore the initial state.We consider the protection of a single-qubit system,derive the analytical expressions of the success probability and the fidelity,and analyze the influence of key parameters on the performance of the proposed scheme.Unlike previous studies,there is no trade-off between the fidelity and the success probability in the proposed scheme;hence one could maximize them separately.Simulation results show that the proposed scheme can greatly improve the fidelity of the quantum state with a certain success probability.Moreover,the proposed scheme is successfully applied to improving the fidelity of controlled quantum teleportation through two independent FTTN channels from the perspective of protecting the shared entanglement.
基金supported by the National Natural Science Foundation of China under grant no.61973290Ministry of Science and Technology of P.R.China Program under the grant no.QN2022200007L。
文摘Quantum teleportation as the key strategy for quantum communication requires pure maximally shared entangled states among quantum nodes.In practice,quantum decoherence drastically degrades the shared entanglement during entanglement distribution,which is a serious challenge for the development of quantum networks.However,most of the decoherence control strategies proposed thus far are either resource-intensive or time-consuming.To overcome this obstacle,we enable noise-resistant teleportation through a noisy channel with a limited number of qubits and without applying time-consuming weak measurements.We apply a quantum gate control unit consisting of a controlled NOT gate and a rotation gate after the original teleportation protocol is accomplished.Furthermore,we demonstrate that a teleportation fidelity of unity is attainable when environment-assisted measurement is added to the proposed teleportation protocol via quantum gates.Moreover,we present an entanglement distribution process by employing the designed quantum gate control unit followed by the deterministic standard teleportation protocol to improve teleportation fidelity by establishing improved shared entanglement.Our performance analysis indicates that the proposed teleportation schemes offer a competitive fidelity and success probability compared with the conventional schemes and a recent weak measurement-based teleportation protocol.
