Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, United Kingdom.
Phys Rev Lett. 2012 Feb 10;108(6):060502. doi: 10.1103/PhysRevLett.108.060502. Epub 2012 Feb 8.
We introduce a new scheme for continuous-variable entanglement distillation that requires only linear temporal and constant physical or spatial resources. Distillation is the process by which high-quality entanglement may be distributed between distant nodes of a network in the unavoidable presence of decoherence. The known versions of this protocol scale exponentially in space and doubly exponentially in time. Our optimal scheme therefore provides exponential improvements over existing protocols. It uses a fixed-resource module-an entanglement distillery-comprising only four quantum memories of at most 50% storage efficiency and allowing a feasible experimental implementation. Tangible quantum advantages are obtainable by using existing off-resonant Raman quantum memories outside their conventional role of storage.
我们提出了一种新的连续变量纠缠蒸馏方案，该方案仅需要线性时间和恒定的物理或空间资源。在不可避免的退相干存在下，蒸馏是在网络的远程节点之间分配高质量纠缠的过程。该协议的已知版本在空间上呈指数级增长，在时间上呈双指数级增长。因此，我们的最佳方案相对于现有协议提供了指数级的改进。它使用了一个固定资源模块——纠缠蒸馏厂，仅由四个量子存储器组成，每个存储器的存储效率最高为 50%，并且允许可行的实验实现。通过在其传统存储角色之外使用现有的非共振拉曼量子存储器，可以获得实际的量子优势。
