Realization of mutually unbiased bases for a qubit with only one wave plate: theory and experiment.
Realization of mutually unbiased bases for a qubit with only one wave plate: theory and experiment.
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DOI：
10.1364/oe.23.010018
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发表时间：
2015-03
期刊：
影响因子：
3.8
通讯作者：
Z. Hou;G. Xiang;D. Dong;Chuan‐Feng Li;G. Guo
中科院分区：
文献类型：
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作者：
Z. Hou;G. Xiang;D. Dong;Chuan‐Feng Li;G. Guo
我们考虑的问题，实现相互无偏基地（MUB）的偏振量子比特只有一个波片，波片的最小数量。我们发现，只要其相移（模360°）范围在45°和315°之间，一个波片就足以实现两个MUB。如果波片的相移在[111.5°，141.7 °]或其关于180°的对称范围内，它可以实现三个MUB（一个量子比特的完整MUB集）。计算表明，使用相位为120°的三分之一波片（TWP）实现的MUB的系统误差是使用四分之一波片（QWP）和半波片（HWP）组合实现的MUB的系统误差的一半。作为实验应用，TWP被用于单量子比特和双量子比特量子态层析成像实验，结果显示系统误差减少了50%。该技术不仅节省了一块波片，而且减小了系统误差，可应用于量子态层析成像等涉及MUB的应用。提出的TWP可能成为一种有用的仪器在光学实验中，取代多个元件，如QWP和HWP。
We consider the problem of implementing mutually unbiased bases (MUB) for a polarization qubit with only one wave plate, the minimum number of wave plates. We show that one wave plate is sufficient to realize two MUB as long as its phase shift (modulo 360°) ranges between 45° and 315°. It can realize three MUB (a complete set of MUB for a qubit) if the phase shift of the wave plate is within [111.5°, 141.7°] or its symmetric range with respect to 180°. The systematic error of the realized MUB using a third-wave plate (TWP) with 120° phase is calculated to be a half of that using the combination of a quarter-wave plate (QWP) and a half-wave plate (HWP). As experimental applications, TWPs are used in single-qubit and two-qubit quantum state tomography experiments and the results show a systematic error reduction by 50%. This technique not only saves one wave plate but also reduces the systematic error, which can be applied to quantum state tomography and other applications involving MUB. The proposed TWP may become a useful instrument in optical experiments, replacing multiple elements like QWP and HWP.