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arXiv 1004.5573quant-ph
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噪声量子信道上的最优超密集编码

Optimal super dense coding over noisy quantum channels

Zahra Shadman, Hermann Kampermann, Chiara Macchiavello, Dagmar Bruss

摘要:

研究了在噪声存在下的超密集编码,即纠缠资源态的子系统在发送端和接收端之间必须通过一个有噪声的单位量子信道。我们明确讨论了任意维Pauli信道的情况,并导出了在某些给定的资源状态下的超密集编码容量(即最优信息传输)。我们还研究了初始资源状态可以选择的情况:对于量子比特去极化信道,我们证明了噪声参数存在一个阈值,低于该阈值,超密集编码协议由最大纠缠初始状态优化,而高于阈值,任何纠缠初始状态的密集编码容量小于一个产品状态。最后,我们提供了一个有噪声的信道的例子,其中非酉预处理增加了超密集编码容量,相比,只有酉编码。

英文摘要:

We investigate super dense coding in the presence of noise, i.e. the subsystems of the entangled resource state have to pass a noisy unital quantum channel between the sender and the receiver. We discuss explicitly the case of Pauli channels in arbitrary dimension and derive the super dense coding capacity (i.e. the optimal information transfer) for some given resource states. We also study the case that the initial resource state can be chosen: for the qubit depolarizing channel we show that there is a threshold value for the noise parameter, below which the super dense coding protocol is optimized by a maximally entangled initial state, while above the threshold the dense coding capacity for any entangled initial state is smaller than the one for a product state. Finally, we provide an example of a noisy channel where non-unitary pre-processing increases the super dense coding capacity, as compared to only unitary encoding.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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