Hard limits on the postselectability of optical graph states
Hard limits on the postselectability of optical graph states
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DOI：
10.1088/2058-9565/aae950
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发表时间：
2018-06
影响因子：
6.7
通讯作者：
J. Adcock;S. Morley-Short;J. Silverstone;M. Thompson
中科院分区：
文献类型：
--
作者：
J. Adcock;S. Morley-Short;J. Silverstone;M. Thompson
大纠缠图态的相干控制使各种量子信息处理任务成为可能，包括纠错的量子计算。线性光学方法提供了极好的控制和一致性，但今天大多数光子源和纠缠门--构建大的图态所需的--都是概率的，依赖于后选择。在这项工作中，我们提供了证据和启发式方法，以帮助实验设计使用后选择。我们为后选择实验引入了一种通用的设计规则：以图的形式绘制，以量子比特为顶点，以门和光子对源为边，一个实验可能只包含奇数个源的圈。我们分析了使用后选择的光子对源的光子的实验，并给出了包含一棵树的非简并情况-图态纠缠类中图态纠缠的可访问类数的下界。然而，选择后可访问的图形状态的比例会迅速缩小。我们列出了各种资源状态的可访问类，最多可达9个量子比特。最后，我们将这些方法应用于近期的多光子实验。
Coherent control of large entangled graph states enables a wide variety of quantum information processing tasks, including error-corrected quantum computation. The linear optical approach offers excellent control and coherence, but today most photon sources and entangling gates—required for the construction of large graph states—are probabilistic and rely on postselection. In this work, we provide proofs and heuristics to aid experimental design using postselection. We introduce a versatile design rule for postselectable experiments: drawn as a graph, with qubit as vertices and gates and photon-pair sources as edges, an experiment may only contain cycles with an odd number of sources. We analyse experiments that use photons from postselected photon-pair sources, and lower bound the number of accessible classes of graph state entanglement in the non-degenerate case—graph state entanglement classes that contain a tree are are always accessible. The proportion of graph states accessible by postselection shrinks rapidly, however. We list accessible classes for various resource states up to 9 qubits. Finally, we apply these methods to near-term multi-photon experiments.