Classical information capacity of a quantum channel
Classical information capacity of a quantum channel
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DOI：
10.1103/physreva.54.1869
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发表时间：
1996-09-01
影响因子：
2.9
通讯作者：
Wootters, WK
中科院分区：
文献类型：
--
作者：
Hausladen, P;Jozsa, R;Wootters, WK
我们考虑经典信息在量子信道上的传输。信道由量子态的“字母表”定义，例如，某些光子偏振，以及这些状态必须发送的一组指定概率。如果接收器被限制为对接收到的“字母”状态进行单独的测量，那么Kholevo定理意味着每个字母传输的信息量不能大于字母系综的冯诺依曼熵H。实际上，实际传输的信息量通常远小于H。然而，我们表明，如果发送者使用的分组编码方案组成的码字的选择，尊重字母状态的先验概率，和接收器区分整个字，而不是个别字母，那么每个字母传输的信息可以任意接近H，永远不会超过H。这提供了量子力学中冯诺依曼熵的精确信息论解释。我们将这一结果适用于“超密集”编码，我们认为它的扩展到嘈杂的渠道。
We consider the transmission of classical information over a quantum channel. The channel is defined by an ''alphabet'' of quantum states, e.g., certain photon polarizations, together with a specified set of probabilities with which these states must be sent. If the receiver is restricted to making separate measurements on the received ''letter'' states, then the Kholevo theorem implies that the amount of information transmitted per letter cannot be greater than the von Neumann entropy H of the letter ensemble. In fact the actual amount of transmitted information will usually be significantly less than H. We show, however, that if the sender uses a block coding scheme consisting of a choice of code words that respects the a priori probabilities of the letter states, and the receiver distinguishes whole words rather than individual letters, then the information transmitted per letter can be made arbitrarily close to H and never exceeds H. This provides a precise information-theoretic interpretation of von Neumann entropy in quantum mechanics. We apply this result to ''superdense'' coding, and we consider its extension to noisy channels.