论文标题
集成电路中多光子拆分状态的复杂结构和表征
Complex structure and characterization of multi-photon split states in integrated circuits
论文作者
论文摘要
多光子拆分状态，每个光子处于不同的空间模式，代表了各种量子应用的必要资源，但它们的有效表征仍然是一个开放的问题。在这里，我们制定了其降低的空间密度矩阵的一般结构，并确定了真实和复杂的独立系数的数量，这些系数尤其完全确定了所有光子的区分性。然后，我们表明该密度矩阵可以通过测量静态积分电路中光子干扰后的相关性来充分表征，其中所需的输出量表是亚何时与光子数量相比。我们提出了由分段的耦合波导组成的优化电路设计，代表了线性光学神经网络，该网络最小化了重建误差并促进了对制造偏差的鲁棒性。
Multi-photon split states, where each photon is in a different spatial mode, represent an essential resource for various quantum applications, yet their efficient characterization remains an open problem. Here, we formulate the general structure of their reduced spatial density matrices and identify the number of real and complex-valued independent coefficients, which in particular completely determine the distinguishability of all photons. Then, we show that this density matrix can be fully characterized by measuring correlations after photon interference in a static integrated circuit, where the required outputs scale sub-quadratically versus the number of photons. We present optimized circuit designs composed of segmented coupled waveguides, representing a linear optical neural network, which minimize the reconstruction error and facilitate robustness to fabrication deviations.
