Chinese scientists at the University of Science and Technology of China have made a breakthrough in the field of quantum error correction (QEC) based on superconducting quantum circuits, contributing to the development of quantum computing.

Using the 107-qubit Zuchongzhi 3.2 processor, which can achieve a high-fidelity readout with an error rate of only 0.95 percent within around 300 nanoseconds, the scientist team has successfully implemented an all-microwave leakage suppression architecture on a distance-7 surface code, achieving a significant decrease in the logical error rate by effectively suppressing the leakage of quantum information as the surface code distance increases.

The experimental result also proves that the system is operating below the error correction threshold, and has successfully improved accuracy with corrective measures.

"Just like when many people come to vote, only when each person's judgment is accurate can the vote cast be accurate; otherwise, as the number of voters increases, the vote cast become even less accurate. Therefore, only when the accuracy of each person's vote exceeds a certain threshold can the team's advantage be brought into play. In other words, as the number of qubits increases, the more error corrections are performed, the more accurate the result become," Zhu Xiaobo, a professor with the University of Science and Technology of China, explained.

Achieving "below-threshold" quantum error correction is a long-sought core goal in the global quantum computing field and one of the key milestones to verify whether quantum computing systems can move from prototypes to practical applications. The new technique also provides a more advantageous solution for building million-qubit quantum computers in the future.