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Characterization of systematic errors in direct quantum state measurements

直接量子态测量中系统误差的表征

基本信息

批准号：
19K14620
负责人：
LE BINHO
金额：
$ 1.91万
依托单位：
Kindai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Early-Career Scientists
财政年份：
2019
资助国家：
日本
起止时间：
2019-04-01 至 2020-03-31
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-19K14620/
关键词：
Systematic error Direct state measurement Quantum control Confidence region Systematic errors Quantum error bars

项目摘要

We investigated the systematic operational errors in the direct state measurements (DSM) with a quantum controlled interaction framework. In this scheme, a target system is controlled by a qubit probe and postselected onto a conjugate basis; the outcomes of the control qubit probe can be measured and taken out of the estimated state. We have considered two types of operational interaction: (i) invert quantum controlled interaction (type-I) and (ii) arbitrary strong interaction (type-II), which is equivalent to a von Neumann interaction.We found that type-I gives lower systematic error than type-II, which means more accuracy. For the same confidence level, type-I has a higher ratio into percentage in the confidence region. The systematic error in type-I is also well against the noise as its fidelity is protected under the noise.Our study gives a better solution for quantum state tomography using the quantum controlled measurement scheme (better than conventional strong measurements and weak measurements.) Furthermore, its measurement is simple and applicable to high-dimension systems. This method, thus, could be a potential candidate for further characterizing the properties of large systems.

我们在量子控制的相互作用框架下研究了直接态测量（DSM）中的系统操作误差。在该方案中，目标系统由量子位探针控制并后选到共轭基上；控制量子位探针的结果可以被测量并从估计状态中取出。我们考虑了两种类型的操作相互作用：(i)反向量子控制相互作用（类型- i）和（ii）任意强相互作用（类型- ii），这相当于冯·诺伊曼相互作用。我们发现i型比ii型给出更低的系统误差，这意味着更高的准确性。对于相同的置信水平，i型在置信区域内的占比更高。在噪声的作用下，系统误差的保真度得到了保护，对噪声的抵抗能力也很好。我们的研究为量子态层析成像提供了一个更好的解决方案，使用量子控制的测量方案（优于传统的强测量和弱测量）。此外，它的测量简单，适用于高维系统。因此，这种方法可能是进一步表征大型系统特性的潜在候选方法。