2018/08/08 by Geng Chen, Lijian Zhang, Wen-Hao Zhang +18 · 42 citations
Computer Science · Mathematics · Physics and Astronomy · #Hamiltonian (control theory) #Heisenberg limit #Linear scale #Mathematics #Mechanical and Optical Resonators #Metrology #Nonlinear system #Photon #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum discord #Quantum entanglement #Quantum mechanics #Quantum metrology #Quantum network #Scaling #Statistical physics #Superposition principle #quant-ph
paper · pdf · doi:10.1103/physrevlett.121.060506
published in Physical Review Letters 121(6), 060506 (American Physical Society)
arxiv created 2018/08/08 · openalex publication_date 2018/08/08 · arxiv updated 2018/08/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
It has been suggested that both quantum superpositions and nonlinear interactions are important resources for quantum metrology. However, to date the different roles that these two resources play in the precision enhancement are not well understood. Here, we experimentally demonstrate a Heisenberg-scaling metrology to measure the parameter governing the nonlinear coupling between two different optical modes. The intense mode with n (more than 106 in our work) photons manifests its effect through the nonlinear interaction strength which is proportional to its average photon number. The superposition state of the weak mode, which contains only a single photon, is responsible for both the linear Hamiltonian and the scaling of the measurement precision. By properly preparing the initial state of single photon and making projective photon-counting measurements, the extracted classical Fisher information (FI) can saturate the quantum FI embedded in the combined state after coupling, which is ∼n2 and leads to a practical precision ≃1.2/n. Free from the utilization of entanglement, our work paves a way to realize Heisenberg-scaling precision when only a linear Hamiltonian is involved.