Correlated errors can significantly impact the quantum error correction, which challenges the assumption that errors occur in different qubits independently in both space and time. Superconducting qubits have been found to suffer correlated errors across multiple qubits, which could be attributable to ionizing radiations and cosmic rays. Nevertheless, the direct evidence and a quantitative understanding of this relationship are currently lacking. In this work, we put two cosmic-ray muon detectors directly beneath the sample box in a dilution refrigerator and successfully observe the correlated errors in a superconducting qubit array triggered by muons through monitoring multi-qubit simultaneous charge-parity jumps and bit flips. By introducing a lead shielding layer on the refrigerator, we reveal that the majority of other correlated errors are primarily induced by gamma rays. Furthermore, we find the superconducting film with a higher recombination rate of quasiparticles used in the qubits helps reduce the duration of correlated errors. Our results provide experimental evidence of the impact of gamma rays and muons on superconducting quantum computation and offer practical insights into mitigation strategies for quantum error correction. In addition, we observe the average occurrence rate of muon-induced correlated errors in our processor is approximately 0.40 min−1cm−2 which is comparable to the muon event rate detected by the muon detector with 0.506 min−1cm−2. This demonstrates the potential applications of superconducting qubit arrays as low-energy threshold sensors in the field of high-energy physics.

报告人简介

王骏华于2012年至 2017年在中国科学院大学物理研究所获得博士学位，毕业后于2018 年至 2020 年在四川师范大学物理与电子工程学院担任讲师， 2020年7月至今在北京量子信息科学研究院量子计算研究部任高级工程师。

邀请人

宋宁强 副研究员