Decoherence in collective quantum memories for photons
Decoherence in collective quantum memories for photons
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DOI：
10.1103/physreva.72.022327
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发表时间：
2004-08
影响因子：
2.9
通讯作者：
C. Mewes;M. Fleischhauer
中科院分区：
文献类型：
--
作者：
C. Mewes;M. Fleischhauer
讨论了退相干对基于原子系综的光子量子存储的影响。结果表明，尽管大纠缠的集体存储状态，对应于单光子或光的非经典状态，退相干的灵敏度不与原子的数量成比例。这是由于存储状态的等价类的存在，它们具有相同的投影到相关的准粒子模式（暗态极化激元）。几个退相干过程所造成的不相关的个人水库耦合进行了详细分析：单原子自旋翻转和退相，原子损失，和运动的原子。此外，它表明，集体退相干过程的敏感性，影响所有的极化激元模式具有可比的强度也不增加与原子的数量。
The influence of decoherence on quantum memories for photons based on atomic ensembles is discussed. It is shown that despite the large entanglement of the collective storage states, corresponding to single photons or nonclassical states of light, the sensitivity to decoherence does not scale with the number of atoms. This is due to the existence of equivalence classes of storage states, which have the same projection onto the relevant quasiparticle mode (dark-state polariton). Several decoherence processes resulting from uncorrelated individual reservoir couplings are analyzed in detail: single-atom spin flips and dephasing, atom loss, and motion of atoms. Furthermore, it is shown that the sensitivity to collective decoherence processes that affect all polariton modes with comparable strength does also not increase with the number of atoms.