Quantum repeaters based on atomic ensembles and linear optics
Quantum repeaters based on atomic ensembles and linear optics
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DOI：
10.1103/revmodphys.83.33
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发表时间：
2011-03-21
影响因子：
44.1
通讯作者：
Gisin, Nicolas
中科院分区：
文献类型：
--
作者：
Sangouard, Nicolas;Simon, Christoph;Gisin, Nicolas
长距离量子态的分布受到光子损失的限制。由于不可克隆定理，经典电信中的直接放大在量子通信中不是一种选择。这个问题可以通过实施量子中继器协议来解决，该协议通过纠缠交换从短距离纠缠创建长距离纠缠。此类协议需要能够以一种众所周知的方式创建纠缠，将其存储在量子存储器中，并交换它。实现量子中继器的一种有吸引力的通用策略是基于使用原子系综作为量子存储器，结合线性光学技术和光子计数来执行所有所需的操作。这里回顾了这个非常活跃的领域的理论和实验现状。对不同方法的潜力进行了定量比较，重点是超越光子直接传输的最直接目标。
The distribution of quantum states over long distances is limited by photon loss. Straightforward amplification as in classical telecommunications is not an option in quantum communication because of the no-cloning theorem. This problem could be overcome by implementing quantum repeater protocols, which create long-distance entanglement from shorter-distance entanglement via entanglement swapping. Such protocols require the capacity to create entanglement in a heralded fashion, to store it in quantum memories, and to swap it. One attractive general strategy for realizing quantum repeaters is based on the use of atomic ensembles as quantum memories, in combination with linear optical techniques and photon counting to perform all required operations. Here the theoretical and experimental status quo of this very active field are reviewed. The potentials of different approaches are compared quantitatively, with a focus on the most immediate goal of outperforming the direct transmission of photons.