通过光学参量放大器对连续变量量子态进行严格表征
Rigorous characterization of continuous-variable quantum states via optical parametric amplifiers
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中文总结 AI 辅助
研究针对连续变量量子信息处理中表征非高斯量子态的问题，利用高增益相敏光学参量放大和功率测量，通过半定规划方法及认证框架，实现对奇偶对称量子态的容错表征与认证，为验证复杂量子态提供实用途径。
中文摘要 AI 辅助
表征非高斯量子态对连续变量量子信息处理至关重要，但传统基于零差测量的态层析成像受光学损耗、探测器效率和测量带宽限制。本文引入一种使用高增益相敏光学参量放大和功率测量的容错表征与认证集成框架。通过计算高效的半定规划方法，能从放大的正交测量中忠实重建奇偶对称量子态，放宽探测器效率要求并增加测量带宽。还开发了通过恒星秩见证和维格纳负性直接量化非高斯性的认证框架。通过模拟和实验数据验证了该框架对代表性量子态的有效性。此方法为验证日益复杂的态提供了实用途径，可通过当前量子光子技术轻松实现。
英文摘要
Characterizing non-Gaussian quantum states is of paramount importance for continuous-variable quantum information processing, yet conventional homodyne-measurement-based state tomography remains limited by optical loss, detector efficiency, and measurement bandwidth. Here, we introduce an integrated framework for loss-tolerant characterization and certification using high-gain phase-sensitive optical parametric amplification and power measurements. Our computationally efficient semidefinite programming approach enables faithful reconstruction of parity-symmetric quantum states from amplified quadrature measurements while substantially relaxing detector-efficiency requirements and increasing the measurement bandwidth. We further develop a certification framework that directly quantifies non-Gaussianity via stellar-rank witnesses and Wigner negativity, using the same quadrature-power measurements. We demonstrate the efficacy of the proposed framework through both simulated and experimental data for representative quantum states, including single-photon, Schrodinger cat, and Gottesman-Kitaev-Preskill (GKP) states. By unifying loss-tolerant measurements, state tomography, and nonclassical-state certification within a single experimentally accessible framework, our approach provides a practical pathway toward verifying increasingly complex states and can be readily implemented with current quantum photonic technologies.
