论文标题
纤维通道中多光子极化状态的无腐烂子空间和纠缠猝死
Decoherence-free subspace and entanglement sudden death of multi-photon polarization states in fiber channels
论文作者
论文摘要
量子网络的构建需要多头纠缠状态的长距离传送。在这里，我们研究了纤维通道中GHz和W状态的纠缠动态。在纤维通道中，影响极化纠缠的两个最重要的现象是极化模式色散（PMD）和偏振依赖性损失（PDL）。从理论上讲，我们表征了PMD和PDL载体如何影响三量状态。特别是，在使用并发和纠缠见证人量化输出状态的纠缠后，我们揭示了纠缠猝死（ESD）的发生以及三方系统中无腐蚀的无腐蚀子空间（DSF）的出现。最后，我们在光纤网络中使用任意数量的光子来探索GHz和W状态的演变，并评估纠缠见证人的期望值。
The construction of quantum networks requires long-distance teleportation of multi-qubit entangled states. Here, we investigate the entanglement dynamics of GHZ and W states in fiber channels. In a fiber channel, the two most important phenomena that affect polarization entanglement are polarization mode dispersion (PMD) and polarization-dependent loss (PDL). We theoretically characterize how PMD and PDL vectors affect three-qubit states. In particular, upon quantifying the entanglement at the output states using concurrence and entanglement witness, we reveal the occurrence of entanglement sudden death (ESD) and the appearance of decoherence-free subspaces (DSFs) in tripartite systems. Finally, we explore the evolution of GHZ and W state with an arbitrary number of photons in a fiber network and evaluate the expectation value of the entanglement witness.
