Experimental test of tight state-independent preparation uncertainty relations for qubits
Experimental test of tight state-independent preparation uncertainty relations for qubits
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DOI：
10.1103/physreva.102.042204
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发表时间：
2020-02
影响因子：
2.9
通讯作者：
S. Sponar;Armin Danner;Kazuma Obigane;Simon Hack;Y. Hasegawa
中科院分区：
文献类型：
--
作者：
S. Sponar;Armin Danner;Kazuma Obigane;Simon Hack;Y. Hasegawa
著名的Robertson-Schroedinger测不准关系缺少一个不可约的下界。这被广泛归因于下界的状态依赖性。因此，Abbott {et al.}介绍了一种通用方法来推导量子位测量的紧密状态独立的不确定性关系[数学4，8（2016）]。这种关系用两种不确定性度量来表示，即标准差和熵，两者都是期望值的函数。在这里，我们提出了一个中子光学测试的紧状态无关的制备不确定性关系的非交换泡利自旋观测混合自旋状态。最后的结果，在偏振实验中得到的，再现的理论预测显然为任意初始状态的可变程度的偏振。
The well-known Robertson-Schroedinger uncertainty relations miss an irreducible lower bound. This is widely attributed to the lower bound's state-dependence. Therefore, Abbott \emph{et al.} introduced a general approach to derive tight state-independent uncertainty relations for qubit measurements [Mathematics 4, 8 (2016)]. The relations are expressed in two measures of uncertainty, which are standard deviation and entropy, both functions of the expectation value. Here, we present a neutron optical test of the tight state-independent preparation uncertainty relations for non-commuting Pauli spin observables with mixed spin states. The final results, obtained in a polarimetric experiment, reproduce the theoretical predictions evidently for arbitrary initial states of variable degree of polarization.