Free-Space Quantum Signatures Using Heterodyne Measurements
Free-Space Quantum Signatures Using Heterodyne Measurements
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DOI：
10.1103/physrevlett.117.100503
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发表时间：
2016-09-02
影响因子：
8.6
通讯作者：
Korolkova, Natalia
中科院分区：
文献类型：
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作者：
Croal, Callum;Peuntinger, Christian;Korolkova, Natalia
数字签名保证电子通信的作者身份。目前使用的“经典”签名方案依赖于未经证实的安全性计算假设，而量子签名仅依赖于量子力学定律来签署经典消息。以前的量子签名方案使用了明确的量子测量。然而，此类测量有时不会给出结果，从而降低了协议的效率。在这里，我们改为使用外差检测，尽管总是存在一些不确定性，但它总是给出结果。我们通过嘈杂的 1.6 km 自由空间信道分布签名状态，通过实验证明了在真实环境中的可行性。我们的结果表明，连续可变外差检测提高了此类方案的签名率，因此代表了寻找实用量子签名方案的一个有趣方向。对于传输值范围从 100% 到 10% 的情况，但假设没有其他缺陷的理想实现，签名长度会缩短 2 到 10 倍。与之前的相关实验实现相比，该实现中的签名长度要短几个数量级。
Digital signatures guarantee the authorship of electronic communications. Currently used "classical" signature schemes rely on unproven computational assumptions for security, while quantum signatures rely only on the laws of quantum mechanics to sign a classical message. Previous quantum signature schemes have used unambiguous quantum measurements. Such measurements, however, sometimes give no result, reducing the efficiency of the protocol. Here, we instead use heterodyne detection, which always gives a result, although there is always some uncertainty. We experimentally demonstrate feasibility in a real environment by distributing signature states through a noisy 1.6 km free-space channel. Our results show that continuous-variable heterodyne detection improves the signature rate for this type of scheme and therefore represents an interesting direction in the search for practical quantum signature schemes. For transmission values ranging from 100% to 10%, but otherwise assuming an ideal implementation with no other imperfections, the signature length is shorter by a factor of 2 to 10. As compared with previous relevant experimental realizations, the signature length in this implementation is several orders of magnitude shorter.