论文标题
来自两级波动器的合奏的正频和负频噪声
Positive- and negative-frequency noise from an ensemble of two-level fluctuators
论文作者
论文摘要
基于Bloch-Redfield处理的电荷噪声的分析通常会导致违反波动散失定理。标准的马尔可夫近似（应用于偶联的两级波动器时）可以识别为该故障的主要起源。由此产生的分解速率仅涉及在波动频率下的浴反应，因此完全忽略了频率扩展的影响。一种克服此问题的系统和计算方便的方法是采用观众量方法：通过将辅助值耦合到两级波动器集合中，可以获得$ s（ω）$的分析近似，完全与波动 - 散落定理相一致。我们讨论了在几个频率范围内表现出独特行为的噪声的最终特征，包括$ 1/f $至$ 1/f^2 $交叉，以及交叉频率的温度依赖性。
The analysis of charge noise based on the Bloch-Redfield treatment of an ensemble of dissipative two-level fluctuators generally results in a violation of the fluctuation-dissipation theorem. The standard Markov approximation (when applied to the two-level fluctuators coupled to a bath) can be identified as the main origin of this failure. The resulting decoherence rates only involve the bath response at the fluctuator frequency, and thus completely neglect the effects of frequency broadening. A systematic and computationally convenient way to overcome this issue is to employ the spectator-qubit method: by coupling an auxiliary qubit to the two-level fluctuator ensemble, an analytical approximation for $S(ω)$ fully consistent with the fluctuation-dissipation theorem can be obtained. We discuss the resulting characteristics of the noise which exhibits distinct behavior over several frequency ranges, including a $1/f$ to $1/f^2$ crossover with a $T^3$ temperature dependence of the crossover frequency.
