论文标题
顺序量子随机访问代码的实验证明
Experimental Demonstration of Sequential Quantum Random Access Codes
论文作者
论文摘要
随机访问代码（RAC）是一种策略，将消息编码为较短的消息，以某种方式仍然可以以非平凡的概率恢复任何原始消息。用量子位而不是经典的编码可以提高这种概率，但具有重要的限制：由于标准量子测量引起的干扰，量子位不能多次使用。但是，正如Mohan，Tavakoli和Brunner最近所示的[New J. Phys。 21 083034，（2019）]，弱测量值可以减轻此问题，从而使两个顺序解码器的性能比最好的古典RAC更好。我们使用单个光子在实验上表明这些弱测量值是可行的，并且两个解码器可以实现非经典的成功概率。我们证明了这一点是针对测量强度的不同值，并利用我们的实验结果对它们进行紧密界限，以证明我们设置的准确性。这证明了使用顺序量子RAC进行量子信息任务的可行性，例如对不信任设备的自我测试。
A random access code (RAC) is a strategy to encode a message into a shorter one in a way that any bit of the original can still be recovered with nontrivial probability. Encoding with quantum bits rather than classical ones can improve this probability, but has an important limitation: due to the disturbance caused by standard quantum measurements, qubits cannot be used more than once. However, as recently shown by Mohan, Tavakoli, and Brunner [New J. Phys. 21 083034, (2019)], weak measurements can alleviate this problem, allowing two sequential decoders to perform better than with the best classical RAC. We use single photons to experimentally show that these weak measurements are feasible and nonclassical success probabilities are achievable by two decoders. We prove this for different values of the measurement strength and use our experimental results to put tight bounds on them, certifying the accuracy of our setting. This proves the feasibility of using sequential quantum RACs for quantum information tasks such as the self-testing of untrusted devices.
