发表机构
École polytechnique de Montréal（蒙特利尔理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出利用JSA张量结构优化零差探测的本地振荡器，通过HOSVD求解最优LO并界定可见度，为多光子态探测提供实用设计方法。
AI 中文摘要
我们提出了一个框架，通过利用多光子数态联合频谱幅度（JSA）的张量结构，优化用于零差探测的脉冲本地振荡器（LO）。我们证明，寻找最优LO等价于计算JSA张量的主导酉特征对，并且JSA的Tucker高阶奇异值分解（HOSVD）的因子矩阵与光子数态单粒子约化密度矩阵的施密特模式一致。我们使用HOSVD来界定最优零差可见度，并初始化基于梯度的优化。在模拟的JSA中，弱相关、少模态达到接近单位可见度，其中主导HOSVD模式即为最优LO，而强相关、多模态则需要完全优化，即使在真正最优处也饱和于单位可见度以下。这些结果为使用现实光子数态源的零差探测实验设计LO提供了实用途径，有助于非高斯量子态源的实际实现。
英文摘要
We propose a framework for optimizing pulsed local oscillators (LO) for homodyne detection of multiphoton-number states by exploiting the tensor structure of their joint-spectral amplitude (JSA). We show that finding the optimal LO is equivalent to computing the JSA tensor's leading unitary eigenpair and that the factor matrices of the JSA's Tucker higher-order singular value decomposition (HOSVD) coincide with the Schmidt modes of the photon number state's single-particle reduced density matrix. We use the HOSVD to bound the optimal homodyne visibility and to initialize gradient based optimization. In simulated JSAs, weakly correlated, few-mode states reach near-unity visibility, with the leading HOSVD mode being the optimal LO, while strongly correlated, multimode states require full optimization and saturate below unit visibility even at the true optimum. These results offer a practical route to design LOs for homodyne detection experiments with realistic sources of photon-number states, which contributes to the practical implementation of sources of non-Gaussian quantum states.
