Quantum network is a physical device that stores, processes and transmits quantum information based on the laws of quantum mechanics. It is the basis for realizing quantum communication and large-scale quantum computing.Professor Duan Luming’s research group at the Institute of Cross-Information, Tsinghua UniversityUtilizing dual-type qubit encoding of the same kind of ions, it is the first time in the world to realize crosstalk-free quantum network nodes.It is of great significance to the future realization of quantum communication and large-scale quantum computing. The research results were recently published in the international academic journal Nature Communications.
Huang Yuanyuan, an assistant researcher at the Institute of Cross-Information at Tsinghua University, said that they used two pairs of ultra-fine energy level structures of the same kind of ions to respectively encode the "communication bits" used to entangle photons and the "storage bits" used to store information in the quantum network. At the same time, microsecond-level coherent conversion between two qubits was also achieved using lasers.
Experiments have found that communication bits prepared by this method can generate ion-photon entanglement within hundreds of milliseconds; the spin echo method can extend the storage life of storage bits and achieve storage qubits with coherence times on the order of seconds. By comparing the fidelity changes of the stored bits with and without the ion-photon entanglement generation operation,The researchers confirmed crosstalk errors between the two qubits below experimental accuracy, enabling a crosstalk-free quantum network node.