标题： 检测单个光子并不总是证明光子概率幅干涉的必要条件 显示英文标题

标题： Detecting single photons is not always necessary to evidence interference of photon probability amplitudes

摘要： 从量子光学实验中减去偶然符合是一个常见的做法。 对于零均值高斯态，如压缩真空态，我们表明如果去除偶然符合，测量结果在定量上是相同的，无论是对于非常低通量的光子符合，还是对于强度协方差。 因此，纯量子效应，如光子波函数的干涉或光子聚集，在自发下转换产生的宏观光束的涨落相关性中被再现。 在实验中，当检测分辨率小于相干单元（模式尺寸）时，以及在基于采样Wigner函数的随机模拟中，都是如此。 我们讨论了这种对应关系的局限性，例如贝尔不等式（无法减去偶然符合），高度多模的情况，如量子成像，以及高阶相关性。 显示英文摘要

摘要： Subtracting accidental coincidences is a common practice quantum optics experiments. For zero mean Gaussian states, such as squeezed vacuum, we show that if one removes accidental coincidences the measurement results are quantitatively the same, both for photon coincidences at very low flux and for intensity covariances. Consequently, pure quantum effects at the photon level, like interference of photon wave functions or photon bunching, are reproduced in the correlation of fluctuations of macroscopic beams issued from spontaneous down conversion. This is true both in experiment if the detection resolution is smaller than the coherence cell (size of the mode), and in stochastic simulations based on sampling the Wigner function. We discuss the limitations of this correspondence, such as Bell inequalities (for which one cannot substract accidental coincidences), highly multimode situations such as quantum imaging, and higher order correlations.