发表机构
University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对非相同量子信道，提出纠缠辅助的普适编码解码策略，提升最坏情况保真度，在去极化信道下最优，并扩展至经典信道与量子资源理论。
AI 中文摘要
使用量子信道进行通信通常需要对量子信道的多次相同使用进行编码和解码。在实际场景中，退相干可能严重限制我们这样做的能力，可能导致每次信道使用变得不相同。给定$n$个非相同的信道，我们提出一种纠缠辅助的编码和解码策略，该策略产生一个信道，其最坏情况保真度高于所有$n$个给定信道。该策略是普适的，即无论给定什么信道，只要它们满足对其初始纠缠保真度的温和假设，该提升都成立。当给定信道是去极化信道时，我们的协议是最优的，并且基本上是唯一具有普适性的协议。这一思想也可以扩展到经典信道，其中发送方和接收方之间的共享随机性允许普适地提升正确传输的概率。然后我们考虑一般的量子资源理论，为这种量子资源的普适提升的可能性提供了必要条件和充分条件。
英文摘要
Communication using quantum channels generally requires encoding and decoding on many identical uses of a quantum channel. In practical settings, decoherence may severely limit our ability to do so, potentially rendering each channel use nonidentical. Given $n$ nonidentical channels, we present an entanglement-assisted encoding and decoding strategy that yields a channel with higher worst-case fidelity than all of the $n$ given channels. The strategy is universal, in the sense that the improvement holds regardless of what channels are given, as long as they satisfy mild assumptions on their initial entanglement fidelities. Our protocol is optimal when the given channels are depolarizing channels, and is essentially the unique one that is universal. This idea can also be extended to classical channels, where shared randomness between the sender and the receiver allows universal enhancement of the probability of correct transmission. We then consider general quantum resource theories, providing a necessary condition and a sufficient condition for the possibility of such universal improvement of quantum resources.
Commentscomments welcome
