Anomalous charge noise in superconducting qubits
Anomalous charge noise in superconducting qubits
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DOI：
10.1103/physrevb.100.140503
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发表时间：
2019-10-24
影响因子：
3.7
通讯作者：
McDermott, R.
中科院分区：
文献类型：
--
作者：
Christensen, B. G.;Wilen, C. D.;McDermott, R.
我们使用Ramsey层析成像来表征弱电荷敏感超导量子比特中的电荷噪声。我们发现了一个电荷噪声，其频率为1/f（alpha），超过50年，alpha = 1.93，幅度S-q（1 Hz）= 2.9 x 10（-4）e（2）/Hz。低频噪声的噪声指数和幅度比先前在单电子晶体管上的工作中看到的要大得多，但与其他超导量子比特中的频率噪声的报告一致。此外，我们观察到频繁的大幅度跳跃的偏移电荷超过0.1e，这些大的离散电荷跳跃是不兼容的本地化偶极子两级波动的图片。这些数据揭示了一个意想不到的依赖于设备规模的电荷噪声，并建议模型涉及电荷漂移或波动的补丁电位。
We have used Ramsey tomography to characterize charge noise in a weakly charge-sensitive superconducting qubit. We find a charge noise that scales with frequency as 1/f(alpha) over five decades with alpha = 1.93 and a magnitude S-q(1 Hz) = 2.9 x 10(-4) e(2)/Hz. The noise exponent and magnitude of the low-frequency noise are much larger than those seen in prior work on single electron transistors, yet are consistent with reports of frequency noise in other superconducting qubits. Moreover, we observe frequent large-amplitude jumps in offset charge exceeding 0.1e; these large discrete charge jumps are incompatible with a picture of localized dipolelike two-level fluctuators. The data reveal an unexpected dependence of charge noise on device scale and suggest models involving either charge drift or fluctuating patch potentials.