We analyze theoretically and experimentally cases of asymmetric detection, stimulation, and loss within a quantum nonlinear interferometer of entangled pairs. We show that the visibility of the SU(1,1) interference directly discerns between loss on the measured mode (signal) and the conjugated mode (idler). This asymmetry also affects the phase sensitivity of the interferometer, where coherent seeding is shown to mitigate losses that are suffered by the conjugated mode; therefore increasing the maximum threshold of loss that permits sub-shot-noise phase detection. Our findings can improve the performance of setups that rely on direct detection of entangled pairs, such as quantum interferometry and imaging with undetected photons.

中文翻译：

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通过不对称增强纠缠光子对的传感性能

我们从理论和实验上分析了纠缠对的量子非线性干涉仪内不对称检测、激励和损失的情况。我们表明 SU(1,1) 干扰的可见性直接区分了测量模式（信号）和共轭模式（空闲）上的损耗。这种不对称性也影响了干涉仪的相位灵敏度，其中显示相干种子可以减轻共轭模式遭受的损失；因此增加了允许子散粒噪声相位检测的最大损耗阈值。我们的发现可以提高依赖于直接检测纠缠对的设置的性能，例如量子干涉测量和未检测到的光子成像。