Chinese scientists including Xu Yuan, an assistant researcher at the Southern University of Science and Technology (SUSTech), have made a breakthrough in the field of quantum error correction (QEC) based on superconducting quantum circuits, contributing to the development of quantum computing.
Led by Yu Dapeng, an academician with the Chinese Academy of Sciences, the team extended the storage time of quantum information beyond the break-even point for the first time through repetitive real-time QEC. The findings were published online in the journal Nature.
According to Xu, although quantum information processing based on superconducting quantum circuit system has made great progress in recent years, the error rate of quantum operations is still much higher than that of a classical computer. Therefore, QEC, which protects logical qubits from noises, is extremely important.
Conventional QEC schemes use multiple physical qubits to encode a logical qubit, which not only requires a great number of hardware resources but also adds the number of error channels with increased number of physical qubits, resulting in an awkward situation of “more corrections, more errors.”
This problem has not yet been solved to achieve a positive QEC gain to reach the break-even point, which is defined as the lifetime of the best available physical component in this system.
In this study, the research team developed a quantum system with high coherence performance, implemented an error syndrome detection method with low error rates, and improved the QEC procedure.
As a result, they realized QEC of a logical qubit encoded with discrete photon number states in a single bosonic mode. Through repetitive real-time QEC operations, the storage lifetime of the quantum information has been extended beyond the break-even point.
Other scientists involved in the study include Sun Luyan, an associate professor at Tsinghua University, and Zheng Shibiao, a professor at Fuzhou University.