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arXiv 2006.12412quant-ph
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1/f噪声与量子不确定性

1/f noise and quantum indeterminacy

Kirill A. Kazakov

摘要:

基于傅里叶变换信号的不确定性关系,提出了一种解决导体中1/f电压噪声问题的方法。由于观测量在不同时刻的不可交换性所引起的量子不确定性使得电压自协方差变得模糊不清,但波动的功率谱仍然是定义明确的。结果表明,功率谱存在一个下界,这与电压关联函数的反对称部分有关。使用Schwinger-Keldysh方法,这个界限是明确计算的情况下,非极化的载流子的抛物线色散,并发现有1/f低频渐近。与InGaAs量子阱中的1/f噪声测量的比较表明,所观察到的噪声水平仅比所建立的界限高几倍。

英文摘要:

An approach to the problem of 1/f voltage noise in conductors is developed based on an uncertainty relation for the Fourier-transformed signal. The quantum indeterminacy caused by non-commutativity of the observables at different times makes the voltage autocovariance ambiguous, but the power spectrum of fluctuations remains well-defined. It is shown that a lower bound on the power spectrum exists, which is related to the antisymmetric part of the voltage correlation function. Using the Schwinger-Keldysh method, this bound is calculated explicitly in the case of unpolarized charge carriers with a parabolic dispersion, and is found to have a 1/f low-frequency asymptotic. A comparison with the 1/f-noise measurements in InGaAs quantum wells is made which shows that the observed noise levels are only a few times higher than the bound established.

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