Author Correction: Impact of ionizing radiation on superconducting qubit coherence
Author Correction: Impact of ionizing radiation on superconducting qubit coherence
复制标题
作者更正：电离辐射对超导量子位相干性的影响
DOI：
10.1038/s41586-020-2754-2
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发表时间：
2020
期刊：
影响因子：
64.8
通讯作者：
Yoder, Jonilyn L.
中科院分区：
文献类型：
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作者：
Vepsäläinen, Antti P.;Karamlou, Amir H.;Orrell, John L.;Dogra, Akshunna S.;Loer, Ben;Vasconcelos, Francisca;Kim, David K.;Melville, Alexander J.;Niedzielski, Bethany M.;Yoder, Jonilyn L.
依赖于量子比特（量子位）的技术需要长相干时间和高保真运算。超导量子比特是实现这些目标的主要平台之一。然而，超导量子比特的相干性受到库珀电子对-断裂的影响。实验观察到的破碎库珀对（称为准粒子）的密度比Bardeen-Cooper-Schrieffer超导理论在平衡状态下预测的值要高几个数量级。先前的研究表明，红外光子大大增加了准粒子密度，但即使在最好的隔离系统中，它仍然比预期的要高得多，这表明存在另一种产生机制。在这里，我们提供的证据表明，来自环境放射性物质和宇宙射线的电离辐射有助于这种观察到的差异。电离辐射的效应导致准粒子密度升高，我们预测这最终会将超导量子比特的相干时间限制在毫秒以内。我们进一步证明了辐射屏蔽降低了电离辐射的通量，从而增加了能量松弛时间。虽然对今天的量子比特影响很小，但减少或减轻电离辐射的影响对于实现容错超导量子计算机至关重要。
Technologies that rely on quantum bits (qubits) require long coherence times and high-fidelity operations. Superconducting qubits are one of the leading platforms for achieving these objectives,. However, the coherence of superconducting qubits is affected by the breaking of Cooper pairs of electrons, –. The experimentally observed density of the broken Cooper pairs, referred to as quasiparticles, is orders of magnitude higher than the value predicted at equilibrium by the Bardeen–Cooper–Schrieffer theory of superconductivity, –. Previous work, –has shown that infrared photons considerably increase the quasiparticle density, yet even in the best-isolated systems, it remains much higher than expected, suggesting that another generation mechanism exists. Here we provide evidence that ionizing radiation from environmental radioactive materials and cosmic rays contributes to this observed difference. The effect of ionizing radiation leads to an elevated quasiparticle density, which we predict would ultimately limit the coherence times of superconducting qubits of the type measured here to milliseconds. We further demonstrate that radiation shielding reduces the flux of ionizing radiation and thereby increases the energy-relaxation time. Albeit a small effect for today’s qubits, reducing or mitigating the impact of ionizing radiation will be critical for realizing fault-tolerant superconducting quantum computers.