Indications of a soft cutoff frequency in the charge noise of a Si/SiGe quantum dot spin qubit
Indications of a soft cutoff frequency in the charge noise of a Si/SiGe quantum dot spin qubit
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DOI：
10.1103/physrevb.99.081301
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发表时间：
2019-02-21
影响因子：
3.7
通讯作者：
Kestner, J. P.
中科院分区：
文献类型：
--
作者：
Gungordu, Utkan;Kestner, J. P.
电荷噪声的表征对半导体自旋量子比特界具有重要意义。我们分析了最近一次实验的回波幅度数据[Yoneda et al., Nat. nanotechnology . 13, 102(2018)]，并注意到数据显示在测量范围内的较高频率上与1/f（alpha）噪声功率谱的偏差很小，但一致。我们报告了使用基于两级波动的物理噪声模型来拟合数据的结果，并发现它可以大部分解释偏差。虽然我们的结果是暗示性的，而不是决定性的，但它们提供了可能是电荷噪声高频截止的早期指示。这个截止点的位置，噪声的功率谱密度逐渐从1/f滚到1/f(2)，这是设计精确量子比特控制脉冲的关键知识，我们的数据拟合在200 kHz左右。
Characterizing charge noise is of prime importance to the semiconductor spin qubit community. We analyze the echo amplitude data from a recent experiment [Yoneda et al., Nat. Nanotechnol. 13, 102 (201 8)] and note that the data show small but consistent deviations from a 1/f(alpha) noise power spectrum at the higher frequencies in the measured range. We report the results of using a physical noise model based on two-level fluctuators to fit the data and find that it can mostly explain the deviations. While our results are suggestive rather than conclusive, they provide what may be an early indication of a high-frequency cutoff in the charge noise. The location of this cutoff, where the power spectral density of the noise gradually rolls off from 1/f to 1/f(2), crucial knowledge for designing precise qubit control pulses, is given by our fit of the data to be around 200 kHz.