论文标题

在嘈杂的稳定器状态下本地化真正的多方纠缠

Localizing genuine multiparty entanglement in noisy stabilizer states

论文作者

J., Harikrishnan K., Pal, Amit Kumar

论文摘要

使用真正的多方纠缠来表征大型嘈杂的多方量子状态是一项具有挑战性的任务。在本文中,我们计算了在无嘈杂和嘈杂的场景中选择的多阶多方子系统上定位的真实多党纠缠的下限。在没有噪声的情况下,采用基于图的技术,我们对任意图状态的计算作为稳定器状态的代表,并表明计算所需的图操作具有与系统大小的多项式缩放。作为示范,我们计算了具有线性,梯子和平方结构的大图的子系统的局部真实多方纠缠。我们还扩展了在所有量子位上受到单量子马尔可维亚或非马尔可维式的Pauli噪声的图形状态的计算,并证明,对于与特定的Pauli测量设置相对应的特定真实多方纠缠的特定下限,与特定的Pauli测量设置相对应,除此之外,所有关键噪声强度的存在都是临界噪声强度的,所有这些都可以实现。由于稳定器状态和图形状态之间的局部统一连接,该计算对于在噪声下的任意大稳定剂状态也很有用。我们通过考虑在平方晶格上定义的感谢您的代码,并在代码的非平凡环上计算出可本地化的真实多方纠缠的下限来证明这一点。与图态相似,我们还显示了这种情况下的临界噪声强度的存在,并讨论了其有趣的特征。

Characterizing large noisy multiparty quantum states using genuine multiparty entanglement is a challenging task. In this paper, we calculate lower bounds of genuine multiparty entanglement localized over a chosen multiparty subsystem of multi-qubit stabilizer states in the noiseless and noisy scenario. In the absence of noise, adopting a graph-based technique, we perform the calculation for arbitrary graph states as representatives of the stabilizer states, and show that the graph operations required for the calculation has a polynomial scaling with the system size. As demonstrations, we compute the localized genuine multiparty entanglement over subsystems of large graphs having linear, ladder, and square structures. We also extend the calculation for graph states subjected to single-qubit Markovian or non-Markovian Pauli noise on all qubits, and demonstrate, for a specific lower bound of the localizable genuine multiparty entanglement corresponding to a specific Pauli measurement setup, the existence of a critical noise strength beyond which all of the post measured states are biseparable. The calculation is also useful for arbitrary large stabilizer states under noise due to the local unitary connection between stabilizer states and graph states. We demonstrate this by considering a toric code defined on a square lattice, and computing a lower bound of localizable genuine multiparty entanglement over a non-trivial loop of the code. Similar to the graph states, we show the existence of the critical noise strength in this case also, and discuss its interesting features.

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