Observation of detection-dependent multi-photon coherence times
Observation of detection-dependent multi-photon coherence times
复制标题
依赖于检测的多光子相干时间的观察
作者：
Y. Ra;M. Tichy;Hyang;O. Kwon;F. Mintert;A. Buchleitner;Yoon
相干时间是决定实验中是否观察到干涉的最关键参数之一。对于光子，它传统上由光子的有效光谱带宽确定。在这里，我们报告的多光子干涉实验中的多光子相干时间，定义的干涉信号的宽度，取决于干涉光子的数量和测量方案选择检测粒子。理论分析表明，所有的多光子干涉与两个以上的粒子的功能，这种依赖性，这可以归因于高阶效应的粒子的相互不相容性。一个惊人的结果是，一个单一的、定义明确的多粒子量子态可以表现出不同程度的干涉，这取决于所选择的可观察性。因此，在多粒子量子干涉测量中，只有选择合适的探测方案才能获得最佳的灵敏度。相干时间描述了粒子仍然可以显示波状干涉的时间尺度，对量子光学很重要。使用多光子干涉实验，Ra等人表明多光子相干时间取决于光子数量和所使用的检测方案。
The coherence time constitutes one of the most critical parameters that determines whether or not interference is observed in an experiment. For photons, it is traditionally determined by the effective spectral bandwidth of the photon. Here we report on multi-photon interference experiments in which the multi-photon coherence time, defined by the width of the interference signal, depends on the number of interfering photons and on the measurement scheme chosen to detect the particles. A theoretical analysis reveals that all multi-photon interferences with more than two particles feature this dependence, which can be attributed to higher-order effects in the mutual indistinguishability of the particles. As a striking consequence, a single, well-defined many-particle quantum state can exhibit qualitatively different degrees of interference, depending on the chosen observable. Therefore, optimal sensitivity in many-particle quantum interferometry can only be achieved by choosing a suitable detection scheme. The coherence time describes the timescale over which particles can still display wave-like interference and is important for quantum optics. Using multi-photon interference experiments, Ra et al. show that the multi-photon coherence time depends on both the number of photons and the detection scheme used.