Lamas-Linares A, Howell J C, Bouwmeester D
Centre for Quantum Computation, Clarendon Laboratory, University of Oxford, UK.
Nature. 2001 Aug 30;412(6850):887-90. doi: 10.1038/35091014.
Entangled photon pairs-discrete light quanta that exhibit non-classical correlations-play a crucial role in quantum information science (for example, in demonstrations of quantum non-locality, quantum teleportation and quantum cryptography). At the macroscopic optical-field level non-classical correlations can also be important, as in the case of squeezed light, entangled light beams and teleportation of continuous quantum variables. Here we use stimulated parametric down-conversion to study entangled states of light that bridge the gap between discrete and macroscopic optical quantum correlations. We demonstrate experimentally the onset of laser-like action for entangled photons, through the creation and amplification of the spin-1/2 and spin-1 singlet states consisting of two and four photons, respectively. This entanglement structure holds great promise in quantum information science where there is a strong demand for entangled states of increasing complexity.
纠缠光子对——呈现非经典关联的离散光量子——在量子信息科学中起着至关重要的作用（例如，在量子非局域性、量子隐形传态和量子密码学的演示中）。在宏观光场层面，非经典关联也可能很重要，比如在压缩光、纠缠光束以及连续量子变量的隐形传态的情况中。在这里，我们利用受激参量下转换来研究光的纠缠态，这种纠缠态弥合了离散和宏观光学量子关联之间的差距。我们通过分别创建和放大由两个和四个光子组成的自旋 - 1/2 和自旋 - 1 单重态，实验证明了纠缠光子的类激光行为的出现。这种纠缠结构在对日益复杂的纠缠态有强烈需求的量子信息科学中具有巨大潜力。
