论文标题
具有可分离状态的超敏感量子计量学
Super-Sensitive Quantum Metrology with Separable States
论文作者
论文摘要
我们引入了一种超敏感的相测量技术，该技术在不使用挤压状态或多个粒子纠缠状态的情况下产生海森堡极限。取而代之的是，我们使用多个粒子可分离的量子态探测该相，然后通过单粒子干扰检索相位。从未检测到物理探测相的颗粒。我们的方案涉及没有巧合测量或许多粒子干扰，但仍表现出相位超分辨率。我们还详细分析了探测颗粒的损失如何影响测量灵敏度，并发现损失导致许多粒子纠缠的产生和测量敏感性的降低。当损失最大时，系统会产生许多颗粒的Greenberger-Horne-Zeilinger（GHz）状态，并且由于非常高相的不确定性，相位测量变得不可能。与使用涉及两个或多个粒子作为关键资源的纠缠的超敏感相测量技术形成鲜明对比的是，我们的方法表明，在量子计量学上具有多个粒子纠缠可以适得其反。
We introduce a super-sensitive phase measurement technique that yields the Heisenberg limit without using either a squeezed state or a many-particle entangled state. Instead, we use a many-particle separable quantum state to probe the phase and we then retrieve the phase through single-particle interference. The particles that physically probe the phase are never detected. Our scheme involves no coincidence measurement or many-particle interference and yet exhibits phase super-resolution. We also analyze in detail how the loss of probing particles affects the measurement sensitivity and find that the loss results in the generation of many-particle entanglement and the reduction of measurement sensitivity. When the loss is maximum, the system produces a many-particle Greenberger-Horne-Zeilinger (GHZ) state, and the phase measurement becomes impossible due to very high phase uncertainty. In striking contrast to the super-sensitive phase measurement techniques that use entanglement involving two or more particles as a key resource, our method shows that having many-particle entanglement can be counterproductive in quantum metrology.
