Quantum states can be efficiently transferred over a long distance if the entire quantum channel can be divided into several small blocks. We consider a scenario in which each block consists of two copies of a multiparty state -- one is used for distributing an arbitrary quantum state to multiple parties while the other channel is required to concentrate it back to a single party. Both in noiseless and local noisy scenarios, we find one-shot quantum capacities of these channels in terms of fidelity, when the initial shared states in each block are the generalized Greenberger-Horne-Zeilinger and the generalized W states. We also consider a situation where optimal local measurements transform multipartite states to bipartite ones which can then be used as single-path channels for quantum state transmission in each segment. We show that in some parameter ranges, the former protocol provides strictly better fidelities than that of the latter, thereby establishing the importance of distributing and concentrating arbitrary quantum states via multipartite entangled states in long distance quantum communication, over the local measurement based protocol. Moreover, we show that in presence of bit flip or bit-phase flip noise, shared generalized Greenberger-Horne-Zeilinger states possess an inherent noise detection and correction mechanism, leading to the same fidelity as in the noiseless case. We consider further noise models also, which do not enjoy the same mechanism.

中文翻译：

---

通过多条高速公路运输量子货物的效率如何？

如果整个量子通道可以分成几个小块，则量子态可以长距离有效地传输。我们考虑一个场景，其中每个块由多方状态的两个副本组成——一个用于将任意量子状态分发给多方，而另一个通道需要将其集中回单方。在无噪声和局部噪声场景中，当每个块中的初始共享状态是广义 Greenberger-Horne-Zeilinger 和广义 W 状态时，我们在保真度方面找到了这些通道的一次性量子容量。我们还考虑了一种情况，其中最优局部测量将多部分状态转换为二部分状态，然后可以将其用作每个段中量子状态传输的单路径通道。我们表明，在某些参数范围内，前一种协议提供了比后者更好的保真度，从而确定了通过基于局部测量的协议在长距离量子通信中通过多方纠缠态分布和集中任意量子态的重要性。此外，我们表明，在存在位翻转或位相位翻转噪声的情况下，共享的广义 Greenberger-Horne-Zeilinger 状态具有固有的噪声检测和校正机制，导致与无噪声情况相同的保真度。我们还考虑了更多的噪声模型，它们不享有相同的机制。从而确定了通过基于本地测量的协议在长距离量子通信中通过多方纠缠态分布和集中任意量子态的重要性。此外，我们表明，在存在位翻转或位相位翻转噪声的情况下，共享的广义 Greenberger-Horne-Zeilinger 状态具有固有的噪声检测和校正机制，导致与无噪声情况相同的保真度。我们还考虑了更多的噪声模型，它们不享有相同的机制。从而确定了通过基于本地测量的协议在长距离量子通信中通过多方纠缠态分布和集中任意量子态的重要性。此外，我们表明，在存在位翻转或位相位翻转噪声的情况下，共享的广义 Greenberger-Horne-Zeilinger 状态具有固有的噪声检测和校正机制，导致与无噪声情况相同的保真度。我们还考虑了更多的噪声模型，它们不享有相同的机制。导致与无噪声情况相同的保真度。我们还考虑了更多的噪声模型，它们不享有相同的机制。导致与无噪声情况相同的保真度。我们还考虑了更多的噪声模型，它们不享有相同的机制。