Enhancing Phase Estimation in a Hybrid Interferometer via Kerr Nonlinearity and Photon Subtraction
通过Kerr非线性与光子子traction增强混合干涉仪的相位估计
Lifen Guo, Qingqian Kang, Zekun Zhao, Jifeng Sun, Teng Zhao, Cunjin Liu, Xin Su, Liyun Hu
AI总结 本文提出了一种高精度相位估计方案,通过结合Kerr非线性相位移器和多光子子traction操作,实现了超越标准量子极限和常规海森堡标度的相位灵敏度,接近超海森堡标度。
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我们提出了一种高精度相位估计方案,通过协同结合Kerr非线性相位移器和多光子子traction操作,在混合干涉仪中实现高精度相位估计。使用相干态和真空态作为输入资源,我们通过锁相检测系统性地评估了相位灵敏度,并分析了在理想和有损条件下量子 Fisher 信息以及量子 Cramér-Rao 绑定。我们的结果表明,Kerr 非线性和多光子子traction 的联合使用相较于单独使用任何一种技术具有显著优势。所提出的方案使相位灵敏度超越标准量子极限,超过常规海森堡标度(1/N),并接近超海森堡标度(1/N²)——Kerr 非线性的直接结果。更精确地说,超海森堡标度∝1/N²是k=2 Kerr 非线性允许的最终精度极限,并不违反线性相位积累的基本海森堡极限。即使在中等内部光子损失下,系统仍能保持高精度并表现出增强的退相干鲁棒性。Kerr 非线性引入了与光子数平方成正比的强度依赖相位移,而多光子子traction 制造非高斯态以加强相位信息提取。与基于混合干涉仪或SU(1,1)干涉仪的现有方案相比,我们的架构实现了更高的精度和更强的损失鲁棒性。所有组件都可通过当前量子光学技术实验实现。这项工作为实际高精度量子计量和量子传感提供了有前景的途径。
We propose a high-precision phase estimation scheme in a hybrid interferometer by synergistically combining a Kerr nonlinear phase shifter and multi-photon subtraction operations. Using a coherent state and a vacuum state as input resources, we systematically evaluate the phase sensitivity via homodyne detection and analyze the quantum Fisher information as well as the quantum Cramér-Rao bound under both ideal and lossy conditions. Our results show that the joint integration of Kerr nonlinearity and multi-photon subtraction yields remarkable advantages over either technique used alone. The proposed scheme enables the phase sensitivity to surpass the standard quantum limit, exceed the conventional Heisenberg scaling ($1/N$), and approach the super-Heisenberg scaling ($1/N^{2}$)-a direct consequence of Kerr nonlinearity. More precisely, the super-Heisenberg scaling $\propto $ $1/N^{2}$ is the ultimate precision limit permitted by the $k=2$ Kerr nonlinearity and does not violate the fundamental Heisenberg limit for linear phase accumulation. Even under moderate internal photon loss, the system maintains high precision and exhibits enhanced robustness to decoherence. The Kerr nonlinearity introduces an intensity-dependent phase shift proportional to the squared photon number, while multi-photon subtraction tailors non-Gaussian states to strengthen phase information extraction. Compared with existing schemes based on hybrid interferometers or SU(1,1) interferometers, our architecture achieves superior precision and stronger loss resilience. All components are experimentally accessible with current quantum optical technologies. This work provides a promising route for practical high-precision quantum metrology and quantum sensing.