The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits (qubits) are susceptible to two types of error, corresponding to flips of the qubit state about the X and Z directions. Although the Heisenberg uncertainty principle precludes simultaneous monitoring of X- and Z-flips on a single qubit, it is possible to encode quantum information in large arrays of entangled qubits that enable accurate monitoring of all errors in the system, provided that the error rate is low¹. Another crucial requirement is that errors cannot be correlated. Here we characterize a superconducting multiqubit circuit and find that charge noise in the chip is highly correlated on a length scale over 600 micrometres; moreover, discrete charge jumps are accompanied by a strong transient reduction of qubit energy relaxation time across the millimetre-scale chip. The resulting correlated errors are explained in terms of the charging event and phonon-mediated quasiparticle generation associated with absorption of γ-rays and cosmic-ray muons in the qubit substrate. Robust quantum error correction will require the development of mitigation strategies to protect multiqubit arrays from correlated errors due to particle impacts.

构建量子计算机的核心挑战是纠错。与仅易受一种错误影响的经典位不同，量子位（qubits）易受两种错误影响，对应于量子位状态关于X和Z 方向的翻转。尽管海森堡不确定性原理排除了在单个量子位上同时监测X和Z翻转，但可以在纠缠量子位的大型阵列中编码量子信息，从而能够准确监测系统中的所有错误，前提是错误率是低¹. 另一个关键要求是错误不能相互关联。在这里，我们描述了一个超导多量子比特电路，发现芯片中的电荷噪声在超过 600 微米的长度尺度上高度相关；此外，离散电荷跳跃伴随着整个毫米级芯片上量子位能量弛豫时间的强烈瞬态减少。由此产生的相关误差可以用与量子位衬底中 γ 射线和宇宙射线 μ 子吸收相关的充电事件和声子介导的准粒子产生来解释。强大的量子纠错将需要开发缓解策略，以保护多量子位阵列免受由于粒子影响引起的相关错误。