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arXiv 1306.6321quant-ph
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当弱值放大无法抑制技术噪声时

When amplification with weak values fails to suppress technical noise

George C. Knee, Erik M. Gauger

摘要:

后选择应用于弱量子测量会导致弱值现象。以测量强度的单位表示,量子相干测量设备的位移通常由所测量的可观察量的本征谱限定。后选择可以实现干涉效应,使平均位移远远超出此范围,在某些情况下带来实际好处。采用费舍尔信息度量,我们认为,放大位移提供没有根本的优势,由于成功的概率必然降低。我们的理解是一个较低的不确定性估计的未知参数与大量的试验的可能性。我们分析的情况下,检测器是像素化的有限分辨率,并在其中检测器是受随机位移:不完善的参数估计的基本限制降低。令人惊讶的是,对他们来说,弱值放大并不比不利用最终后选择测量所带来的放大效应的技术更稳健。

英文摘要:

The application of postselection to a weak quantum measurement leads to the phenomenon of weak values. Expressed in units of the measurement strength, the displacement of a quantum coherent measuring device is ordinarily bounded by the eigenspectrum of the measured observable. Postselection can enable an interference effect that moves the average displacement far outside this range, bringing practical benefits in certain situations. Employing the Fisher information metric, we argue that the amplified displacement offers no fundamental metrological advantage, due to the necessarily reduced probability of success. Our understanding of metrological advantage is the possibility of a lower uncertainty in the estimate of an unknown parameter with a large number of trials. We analyze a situation in which the detector is pixelated with a finite resolution, and in which the detector is afflicted by random displacements: imperfections which degrade the fundamental limits of parameter estimation. Surprisingly, weak-value amplification is no more robust to them than a technique making no use of the amplification effect brought about by a final, postselected measurement.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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