论文标题
SU（2）-in-in-Su（1,1）嵌套干涉仪，用于高度敏感，耐损失的量子计量学
SU(2)-in-SU(1,1) Nested Interferometer for Highly Sensitive, Loss-Tolerant Quantum Metrology
论文作者
论文摘要
我们对新的干涉仪拓扑结构介绍了实验和理论结果，该拓扑嵌套了SU（2）的干涉仪，例如Mach-Zehnder或Michelson干涉仪，在SU（1,1）干涉仪内部，即Mach-Zehnder干涉仪，具有与参数放大器的Mach-Zehnder干涉仪，代替射击分组。此SU（2）-in-in-Su（1,1）嵌套干涉仪（SISNI）同时达到了高信噪比（SNR），超出标准量子极限（SQL）以外的灵敏度以及对光子损失的耐受性，例如干涉仪外部的探测器，例如检测器。我们使用RB蒸气中的四波混合（FWM）和激光喂养的Mach-Zehnder SU（2）干涉仪实现了SISNI。我们观察到SNR 2.2 dB的路径长度敏感性超出了SQL以外的功率水平（以及SNR）的2个数量级，而不是先前耐受损失的干涉仪的数量级。我们通过实验发现最佳的FWM增益，并找到与FWM过程的最小量子噪声模型的一致性。结果提出了提高高功率干涉仪（例如重力波干涉仪）的实践敏感性的方法，并可以在没有有效探测器的波长下实现高灵敏度，量子增强的干涉法。
We present experimental and theoretical results on a new interferometer topology that nests a SU(2) interferometer, e.g., a Mach-Zehnder or Michelson interferometer, inside a SU(1,1) interferometer, i.e., a Mach-Zehnder interferometer with parametric amplifiers in place of beam splitters. This SU(2)-in-SU(1,1) nested interferometer (SISNI) simultaneously achieves high signal-to-noise ratio (SNR), sensitivity beyond the standard quantum limit (SQL) and tolerance to photon losses external to the interferometer, e.g., in detectors. We implement a SISNI using parametric amplification by four-wave mixing (FWM) in Rb vapor and a laser-fed Mach-Zehnder SU(2) interferometer. We observe path-length sensitivity with SNR 2.2 dB beyond the SQL at power levels (and thus SNR) 2 orders of magnitude beyond those of previous loss-tolerant interferometers. We find experimentally the optimal FWM gains and find agreement with a minimal quantum noise model for the FWM process. The results suggest ways to boost the in-practice sensitivity of high-power interferometers, e.g., gravitational wave interferometers, and may enable high-sensitivity, quantum-enhanced interferometry at wavelengths for which efficient detectors are not available.
