Noise is the central obstacle to building large-scale quantum computers. Quantum systems with sufficiently uncorrelated and weak noise could be used to solve computational problems that are intractable with current digital computers. There has been substantial progress towards engineering such systems^{1,2,3,4,5,6,7,8}. However, continued progress depends on the ability to characterize quantum noise reliably and efficiently with high precision⁹. Here, we describe such a protocol and report its experimental implementation on a 14-qubit superconducting quantum architecture. The method returns an estimate of the effective noise and can detect correlations within arbitrary sets of qubits. We show how to construct a quantum noise correlation matrix allowing the easy visualization of correlations between all pairs of qubits, enabling the discovery of long-range two-qubit correlations in the 14-qubit device that had not previously been detected. Our results are the first implementation of a provably rigorous and comprehensive diagnostic protocol capable of being run on state-of-the-art devices and beyond. These results pave the way for noise metrology in next-generation quantum devices, calibration in the presence of crosstalk, bespoke quantum error-correcting codes¹⁰ and customized fault-tolerance protocols¹¹ that can greatly reduce the overhead in a quantum computation.

噪声是构建大规模量子计算机的主要障碍。具有充分不相关且噪声很小的量子系统可用于解决当前数字计算机难以解决的计算问题。在设计这样的系统^{1,2,3,4,5,6,7,8}方面已经取得了实质性进展。但是，持续的进展取决于以高精度可靠而有效地表征量子噪声的能力⁹。在这里，我们描述了这样的协议，并报告了其在14量子位超导量子体系结构上的实验实现。该方法返回有效噪声的估计值，并可以检测任意组量子位内的相关性。我们展示了如何构建量子噪声相关矩阵，从而可以轻松地可视化所有成对的量子位之间的相关性，从而能够发现以前未检测到的14量子位设备中的远程两量子位相关性。我们的结果是首次实现了可在最先进的设备上运行的严格可靠且全面的诊断协议。这些结果为下一代量子设备中的噪声计量，存在串扰的校准，定制的量子纠错码¹⁰铺平了道路。定制的容错协议¹¹可以大大减少量子计算的开销。