论文标题
量子纠缠的克隆
Cloning of Quantum Entanglement
论文作者
论文摘要
由于量子力学定律，量子无限制是完全克隆任意未知的量子状态的不可能的最根本的限制之一，这是量子力学定律的基础。但是，量子物理学确实允许以不完善的状态保真度和/或概率成功的近似克隆。虽然先前已经测试过单粒子状态的近似量子克隆，但量子纠缠的实验克隆（一种高度不经典的相关性）仍未开发。基于多光子线性光学平台，我们首次演示了两个光子纠缠状态的量子克隆。值得注意的是，我们的结果表明，一个最大纠缠的光子对可以广播为两个纠缠对，均具有高于50 \％的状态保真度。我们的结果是克隆复杂量子系统的关键步骤，并且很可能为量子纠缠提供新的见解。
Quantum no-cloning, the impossibility of perfectly cloning an arbitrary unknown quantum state, is one of the most fundamental limitations due to the laws of quantum mechanics, which underpin the physical security of quantum key distribution. Quantum physics does allow, however, approximate cloning with either imperfect state fidelity and/or probabilistic success. Whereas approximate quantum cloning of single-particle states has been tested previously, experimental cloning of quantum entanglement -- a highly non-classical correlation -- remained unexplored. Based on a multiphoton linear optics platform, we demonstrate quantum cloning of two photon entangled states for the first time. Remarkably our results show that one maximally entangled photon pair can be broadcast into two entangled pairs, both with state fidelities above 50\%. Our results are a key step towards cloning of complex quantum systems, and are likely to provide new insights into quantum entanglement.
