发表机构
Duke University; IBM Research Europe – Zurich; ETH Zurich（杜克大学; IBM欧洲苏黎世研究中心; 苏黎世联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对纯损耗玻色子信道，利用极化码构造了首个显式且可高效解码的纠缠生成协议，达到能量约束量子容量。
AI 中文摘要
虽然噪声信道上量子通信速率的最终极限已得到充分确立，但已知的能够达到这些极限的高效编码方案却很少。这与通过经典信道传输经典数据的情况形成鲜明对比，在经典情形中，极化码和低密度奇偶校验码都能高效地达到任何噪声信道的经典容量。在本工作中，我们构建了一种高效的纠缠生成方案，该方案能够针对一大类信道实现相干信息。对于该类中可降解的信道（包括纯损耗玻色子信道的截断版本），所得方案能够达到量子容量。该构造利用了针对两类经典输入、量子输出（CQ）信道的极化码：一类是输出可交换的信道，另一类是输出为纯态的先验混合（heralded mixtures）的信道。前者可通过经典极化解码算法进行解码，后者则可通过带量子消息的置信传播（BPQM）算法进行解码。据我们所知，该构造是首个显式的、可高效解码的协议，能够达到纯损耗玻色子信道的能量约束量子容量。
英文摘要
While the ultimate limits on the rate of quantum communication over noisy channels are well-established, very few efficient coding schemes achieving these limits are known. This contrasts sharply with transmitting classical data over classical channels, where polar codes and low-density parity-check codes both efficiently achieve the classical capacity of any noisy channel. In this work we construct an efficient entanglement generation scheme which achieves the coherent information for a broad class of channels. For degradable channels in the class, which includes truncated versions of the pure loss Bosonic channel, the resulting scheme achieves the quantum capacity. The construction makes use of polar codes for two kinds of classical-input, quantum-output (CQ) channels: those with commuting outputs and those whose outputs are heralded mixtures of pure states. The former case is amenable to decoding by classical polar decoding algorithms, the latter by the belief propagation with quantum messages (BPQM) algorithm. To our knowledge, this construction is the first explicit and efficiently decodable protocol that achieves the energy-constrained quantum capacity of the pure-loss Bosonic channel.
