Abstract We show how to efficiently send an M-partite entangled state along a spin chain of arbitrary size. Specifically, we show how an entangled M-partite W sate can be almost flawlessly transmitted from one end (Alice) to the other end (Bob) of a spin-1/2 chain described by a slightly modified XX model. We achieve an almost perfect transmission without employing external magnetic fields or modulating the coupling constants among the spins of the chain, the two standard approaches used to achieve a good transmission efficiency. Moreover, the protocol here proposed can be used to transform an M-partite W state with Alice into an M ˜ -partite one with Bob ( M ≠ M ˜ ). We also investigate the proposed protocol's response to several types of disorder and noise and show that it is quite robust to small deviations about the coupling constants of the optimal ordered and noiseless case.

中文翻译：

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通过无序和嘈杂的自旋链几乎完美地传输多部分纠缠

摘要 我们展示了如何沿任意大小的自旋链有效地发送 M 分纠缠态。具体来说，我们展示了一个纠缠的 M 部分 W 状态如何几乎完美地从一个自旋 1/2 链的一端 (Alice) 传输到另一端 (Bob)，由稍微修改的 XX 模型描述。我们在不使用外部磁场或调制链自旋之间的耦合常数的情况下实现了几乎完美的传输，这两种标准方法用于实现良好的传输效率。此外，这里提出的协议可用于将 Alice 的 M 部分 W 状态转换为 Bob 的 M ～ 部分（ M ≠ M ～ ）。我们还调查了提议的协议'