Precise quantum tomography of photon pairs with entangled orbital angular momentum
Precise quantum tomography of photon pairs with entangled orbital angular momentum
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DOI：
10.1088/1367-2630/11/10/103024
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发表时间：
2009-10
影响因子：
3.3
通讯作者：
B. Jack;J. Leach;H. Ritsch;S. Barnett;M. Padgett;S. Franke-Arnold
中科院分区：
文献类型：
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作者：
B. Jack;J. Leach;H. Ritsch;S. Barnett;M. Padgett;S. Franke-Arnold
报道了一种利用轨道角动量(OAM)纠缠实现参数下转换产生的光子对量子态的高保真层析重建方法。我们的层析成像方法允许我们估计下转换的光子之间的纠缠的上下限。我们研究了由OAM状态±ℓ及其叠加定义的二维状态子空间，其中ℓ=1，2，…，30。我们发现，即使对于ℓ=20左右的OAM，重建的密度矩阵也接近于保真度在F=0.979到F=0.814之间的最大纠缠贝尔态的密度矩阵。这表明，尽管单点计数率随着ℓ的增加而减小，但纠缠仍然存在于一个大的维态空间中。
We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ±ℓ and superpositions thereof, with ℓ=1, 2, …, 30. We find that the reconstructed density matrix, even for OAMs up to around ℓ=20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing ℓ, entanglement persists in a large dimensional state space.