Generalized state spaces and nonlocality in fault-tolerant quantum-computing schemes
Generalized state spaces and nonlocality in fault-tolerant quantum-computing schemes
复制标题
容错量子计算方案中的广义状态空间和非局域性
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
S. Virmani
中科院分区：
文献类型：
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作者：
N. Ratanje;S. Virmani
我们发展了广义纠缠概念和量子计算设备之间的联系，其中可用的测量是有限的，要么是因为它们是嘈杂的和/或因为通过设计，他们只是沿着泡利方向。通过考虑限制测量，人们可以（通过考虑对偶正算子）构造不同于通常量子态空间的单粒子态空间。这导致了一个修改后的纠缠概念，它可能与量子版本非常不同（例如，贝尔态可以变得可分离）。我们使用这种方法来开发经典模拟的替代方法，这些方法与非局域相关性的研究有很强的联系：我们构建了噪声量子计算机，这些计算机允许Clifford集之外的操作，并且可以产生某些形式的多方量子纠缠，但在其他方面是经典的，因为它们可以有效地进行经典模拟，并且不能产生非局域统计。虽然该方法提供了新的制度，可以有效地模拟经典的噪声量子演化，它似乎并没有导致显着减少现有的上限，常见的噪声模型的容错阈值。
We develop connections between generalized notions of entanglement and quantum computational devices where the measurements available are restricted, either because they are noisy and/or because by design they are only along Pauli directions. By considering restricted measurements one can (by considering the dual positive operators) construct single-particle-state spaces that are different to the usual quantum-state space. This leads to a modified notion of entanglement that can be very different to the quantum version (for example, Bell states can become separable). We use this approach to develop alternative methods of classical simulation that have strong connections to the study of nonlocal correlations: we construct noisy quantum computers that admit operations outside the Clifford set and can generate some forms of multiparty quantum entanglement, but are otherwise classical in that they can be efficiently simulated classically and cannot generate nonlocal statistics. Although the approach provides new regimes of noisy quantum evolution that can be efficiently simulated classically, it does not appear to lead to significant reductions of existing upper bounds to fault tolerance thresholds for common noise models.