讨论了测量连续变量爱因斯坦波多尔斯基罗森(EPR)关联的两种实验方法。由于在平衡零拍探测和贝尔态直接测量中为标定关联度所选取的参考基准不同,造成谱仪显示的结果有所差异,但经过基准变换,所测得的耦合模压缩度、爱因斯坦波多尔斯基罗森关联度以及它们之间的换算关系均一致。从理论上分析了测量原理,并从实验角度讨论了两种方法的优缺点。

The two methods measuring Einstein-Podolsky-Rosen (EPR) correlation of continuous variables, the balanced homodyne detection and the direct measurement for Bell-state are analytically discussed. In the two detection systems the designated reference levels for the quantum correlation measurement are different, so the displayed results on the spectral analyzer are not identical. After implementing a transformation to the reference level the measured squeezing of coupled mode, EPR correlation and the relation expression between them are totally same. The measurement principle of the two methods is theoretically analyzed and their characteristics are discussed from the requirements of experiments.