Spectral analysis and identification of noises in quantum systems
Spectral analysis and identification of noises in quantum systems
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DOI：
10.1103/physreva.87.022324
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发表时间：
2012-11
影响因子：
2.9
通讯作者：
R. Wu;Tiefu Li;Abraham G. Kofman;Jing Zhang;Yu-xi Liu;Y. Pashkin;J. Tsai;F. Nori
中科院分区：
文献类型：
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作者：
R. Wu;Tiefu Li;Abraham G. Kofman;Jing Zhang;Yu-xi Liu;Y. Pashkin;J. Tsai;F. Nori
在量子信息处理中，了解系统中的噪声对于相干量子操作的高精度操作和层析成像至关重要。现有的识别这种噪声的策略需要使用额外的量子器件或控制脉冲。我们提出了一种直接基于系统对噪声的非马尔可夫响应的集成测量噪声识别方法。通过反转频域中的响应关系来识别噪声谱。举例来说，该方法适用于超导电荷量子位，但它同样适用于任何类型的量子位。我们发现识别策略在最低阶摄动近似下恢复了著名的费米黄金法则，当测量时间远远大于噪声相关时间时对应于马尔可夫极限。除了这种近似之外，还可以通过纳入非马尔可夫状态下的瞬态响应数据来进一步提高所谓最优点的精度。用超导电荷量子比特相干振荡的实验数据对该方法进行了验证。
In quantum information processing, knowledge of the noise in the system is crucial for high-precision manipulation and tomography of coherent quantum operations. Existing strategies for identifying this noise require the use of additional quantum devices or control pulses. We present a noise-identification method directly based on the system's non-Markovian response of an ensemble measurement to the noise. The noise spectrum is identified by reversing the response relationship in the frequency domain. For illustration, the method is applied to superconducting charge qubits, but it is equally applicable to any type of qubits. We find that the identification strategy recovers the well-known Fermi's golden rule under the lowest-order perturbation approximation, which corresponds to the Markovian limit when the measurement time is much longer than the noise correlation time. Beyond such approximation, it is possible to further improve the precision at the so-called optimal point by incorporating the transient response data in the non-Markovian regime. This method is verified with experimental data from coherent oscillations in a superconducting charge qubit.