Department of Physics, Stanford University, Stanford, CA 94305, USA.
Science. 2016 Jun 24;352(6293):1552-5. doi: 10.1126/science.aaf3397.
Quantum metrology exploits entangled states of particles to improve sensing precision beyond the limit achievable with uncorrelated particles. All previous methods required detection noise levels below this standard quantum limit to realize the benefits of the intrinsic sensitivity provided by these states. We experimentally demonstrate a widely applicable method for entanglement-enhanced measurements without low-noise detection. The method involves an intermediate quantum phase magnification step that eases implementation complexity. We used it to perform squeezed-state metrology 8 decibels below the standard quantum limit with a detection system that has a noise floor 10 decibels above the standard quantum limit.
量子计量学利用粒子的纠缠态来提高传感精度，超越了不相关粒子所能达到的极限。以前的所有方法都需要检测噪声水平低于这个标准量子极限，才能实现这些状态提供的固有灵敏度的好处。我们实验证明了一种广泛适用的、无需低噪声检测的纠缠增强测量方法。该方法涉及一个中间量子相位放大步骤，降低了实现的复杂性。我们使用它在检测系统的噪声底高于标准量子极限 10 分贝的情况下，在标准量子极限以下 8 分贝的地方进行压缩态计量。
