Nonlocal generalized quantum measurements of bipartite spin products without maximal entanglement
Nonlocal generalized quantum measurements of bipartite spin products without maximal entanglement
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DOI：
10.1088/1367-2630/abee3f
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发表时间：
2021-03
影响因子：
3.3
通讯作者：
P. Vidil;K. Edamatsu
中科院分区：
文献类型：
--
作者：
P. Vidil;K. Edamatsu
在类空间的分离量子系统上测量非局域可见是一项耗费资源且具有实验挑战性的任务。已经提出了几种理论测量方案来增加其可行性，使用共享的最大纠缠的Ancilla。我们提出了一种新的方法来解决这个问题，使用广义量子测量的语言，以表明实际上有可能测量一个非局域自旋产品可观察到，而不一定需要最大纠缠的Ancilla。这种方法为更经济的任意强度非局部测量打开了大门，其应用范围从非局部弱值到可能的贝尔不等式的新测试。明确了测量强度与所需的辅助纠缠量之间的关系，为将量子非定域性、纠缠和信息传输联系在一起带来了新的视角。
Measuring a nonlocal observable on a space-like separated quantum system is a resource-hungry and experimentally challenging task. Several theoretical measurement schemes have already been proposed to increase its feasibility, using a shared maximally-entangled ancilla. We present a new approach to this problem, using the language of generalized quantum measurements, to show that it is actually possible to measure a nonlocal spin product observable without necessarily requiring a maximally-entangled ancilla. This approach opens the door to more economical arbitrary-strength nonlocal measurements, with applications ranging from nonlocal weak values to possible new tests of Bell inequalities. The relation between measurement strength and the amount of ancillary entanglement needed is made explicit, bringing a new perspective on the links that tie quantum nonlocality, entanglement and information transmission together.