Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2013 Jul 5;111(1):010501. doi: 10.1103/PhysRevLett.111.010501. Epub 2013 Jul 1.
Entanglement is essential to many quantum information applications, but it is easily destroyed by quantum decoherence arising from interaction with the environment. We report the first experimental demonstration of an entanglement-based protocol that is resilient to loss and noise which destroy entanglement. Specifically, despite channel noise 8.3 dB beyond the threshold for entanglement breaking, eavesdropping-immune communication is achieved between Alice and Bob when an entangled source is used, but no such immunity is obtainable when their source is classical. The results prove that entanglement can be utilized beneficially in lossy and noisy situations, i.e., in practical scenarios.
纠缠对于许多量子信息应用至关重要，但它很容易被与环境相互作用产生的量子退相干破坏。我们报告了第一个基于纠缠的协议的实验演示，该协议具有抗损耗和抗噪声能力，可以抵抗破坏纠缠的因素。具体来说，尽管信道噪声超过了纠缠破坏的阈值 8.3dB，但当使用纠缠源时，爱丽丝和鲍勃之间可以实现窃听免疫通信，但当他们的源是经典时，则无法获得这种免疫性。结果证明，纠缠可以在损耗和噪声环境中（即在实际场景中）被有益地利用。
