Correlated charge noise and relaxation errors in superconducting qubits
Correlated charge noise and relaxation errors in superconducting qubits
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DOI：
10.1038/s41586-021-03557-5
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发表时间：
2021-06-17
期刊：
影响因子：
64.8
通讯作者：
McDermott, R.
中科院分区：
文献类型：
--
作者：
Wilen, C. D.;Abdullah, S.;McDermott, R.
构建量子计算机的核心挑战是校正。与仅容易受到一种误差的经典位不同，量子位（Qubits）易受两种类型的误差敏感，对应于X和Z方向的Qubit状态的翻转。尽管海森堡的不确定性原理不能同时监视单个Qubit上的X和Z-Flips，但可以在大量的纠缠量子数组中编码量子信息，从而可以准确地监视系统中的所有错误，但前提是错误率是错误率低1。另一个关键要求是错误无法关联。在这里，我们表征了一个超导的多Quipt电路，并发现芯片中的电荷噪声高于600微米的长度尺度高度相关。此外，离散的电荷跳跃伴随着整个毫米级芯片的量子能量松弛时间的强劲瞬态减少。根据充电事件和声子介导的准粒子产生，与射线和宇宙射线测素相关的Quasiparticle产生来解释所得的相关误差。鲁棒的量子误差校正将需要制定缓解策略，以保护多等级阵列免受由于粒子影响而引起的相关误差。
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.-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.