发表机构
Carleton University（卡尔顿大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出基于奇偶性的时间-bin编码，结合偏振控制延迟线与周期折射率调制实现偏振和时间-bin量子比特间的确定性SWAP操作，还分析了相关错误概率与时间分辨率约束。
AI 中文摘要
多自由度光子量子处理需要在单光子的不同自由度（DOF）量子比特编码之间进行路由，偏振与时间-bin量子比特之间的SWAP操作是这类架构的有利基础组件。然而，传统的早/晚时间-bin编码不支持从晚到早的双向逻辑时间-bin翻转，限制了某些量子操作的实现能力。我们引入一种基于奇偶性的时间-bin编码，其中逻辑态|0⟩_T和|1⟩_T分别对应间距Δt的偶数倍和奇数倍，因此Δt的物理延迟可实现|0⟩_T ↔ |1⟩_T的翻转。这种编码是关键要素，使偏振控制延迟线能够实现CNOT_{P→T}，并与周期折射率调制自然适配以实现CNOT_{T→P}。将三个此类CNOT操作顺序组合，可得到偏振与时间-bin自由度之间的确定性SWAP操作。我们分析了基于场的调制偏振旋转错误概率，以及由电光调制器（EOM）驱动电子设备和光子探测共同设定的时间分辨率约束。
英文摘要
Multi-degree-of-freedom photonic quantum processing requires routing between degree-of-freedom (DOF) qubit encodings on a single photon. A SWAP between polarization and time-bin qubits is Multi-degree-of-freedom photonic quantum processing requires routing between degree-of-freedom (DOF) qubit encodings on a single photon. A SWAP between polarization and time-bin qubits is an advantageous primitive for such architectures, however conventional early/late time-bin encoding does not support bidirectional logical time-bin flips from late to early which limits the ability to implement certain quantum operations. We introduce a parity-based time-bin encoding in which logical $\vert 0 \rangle_T$ and $\vert 1 \rangle_T$ correspond to even and odd multiples of a spacing $Δt$, so that a physical delay of $Δt$ implements $\vert 0 \rangle_T \leftrightarrow \vert 1 \rangle_T$. This encoding is the enabling ingredient that makes a polarization-controlled delay line implement $\mathrm{CNOT}_{P \rightarrow T}$ and aligns naturally with periodic refractive index modulation for $\mathrm{CNOT}_{T \rightarrow P}$. Composing three such CNOT operations sequentially results in a deterministic SWAP between polarization and time-bin degrees of freedom. We analyze field-based modulation polarization-rotation error probability and timing-resolution constraints set by both EOM drive electronics and photon detection.
