连 续 变 量 全 光 量 子 纠 缠 交 换 抗 损 耗 特 性 研 究（特 邀）

Quantum entanglement swapping plays a crucial role in quantum communication by enabling entanglement establishment between two particles that have never directly interacted. For bipartite continuous-variable system, the entanglement characteristics are typically witnessed by the positivity under the partial transposition (PPT) criterion. The entanglement degree is inversely related to the smallest symplectic eigenvalue of covariance matrices-smaller values indicate stronger entanglement. This study theoretically investigates the impact of optical loss on all-optical entanglement swapping by introducing vacuum fields through beam splitters placed in light beam transmission paths to simulate experimental losses. Through theoretical calculations, we found that the all-optical channel between Claire and Bob of alloptical entanglement swapping is highly loss resistant. This work is of great significance for promoting the practical application of all-optical entanglement swapping in quantum network construction.