Entanglement verification with realistic measurement devices via squashing operations
Entanglement verification with realistic measurement devices via squashing operations
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DOI：
10.1103/physreva.81.052342
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发表时间：
2010-05-01
影响因子：
2.9
通讯作者：
Luetkenhaus, Norbert
中科院分区：
文献类型：
--
作者：
Moroder, Tobias;Guehne, Otfried;Luetkenhaus, Norbert
量子信息科学中的许多协议和实验都是以量子比特的简单测量来描述的。然而，在真实的实现中，精确的描述是更困难的，并且使用更复杂的可观测量。问题是，如果考虑到现实模型和简化模型之间的差异，简化描述中的纠缠主张是否仍然成立。我们表明，一个积极的纠缠声明仍然有效，如果有一定的正线性映射连接两个premissions-一个所谓的挤压操作-存在，然后纠缠量的下限也是可能的。我们将我们的结果仅使用阈值探测器的光子的偏振测量，并推导出程序下，多光子事件可以忽略不计。
Many protocols and experiments in quantum information science are described in terms of simple measurements on qubits. However in a real implementation the exact description is more difficult and more complicated observables are used. The question arises whether a claim of entanglement in the simplified description still holds, if the difference between the realistic and simplified models is taken into account. We show that a positive entanglement statement remains valid if a certain positive linear map connecting the two descriptions-a so-called squashing operation-exists; then lower bounds on the amount of entanglement are also possible. We apply our results to polarization measurements of photons using only threshold detectors, and derive procedures under which multiphoton events can be neglected.