论文标题
量子非约束量子读数的有效表征
Efficient characterization of quantum nondemolition qubit readout
论文作者
论文摘要
我们研究了本文量子测量的性能的定量表征。特别地，量子量距离的量子非态度（QND）读数的反作用性质通过量子痕量距离充分量化。仅需要考虑计算基础状态。最重要的是，我们提出了一种基于经典的痕量距离来评估QND保真度的实验高效方法，该痕量使用实验方案进行两次连续测量。测量的三个关键量化符，即QND保真度，读数保真度和投影率，可以直接从同一实验方案中得出。此外，我们介绍了这三个因素之间的关系。超导码头的分散读数的理论仿真结果显示了拟议的QND保真度的有效性。测量性能的有效量化对于测量设备的诊断，性能改善和设计具有实际意义。
We study the quantitative characterization of the performance of qubit measurements in this paper. In particular, the back-action evading nature of quantum nondemolition (QND) readout of qubits is fully quantified by quantum trace distance. Only computational basis states are necessary to be taken into consideration. Most importantly, we propose an experimentally efficient method to evaluate the QND fidelity based on the classical trace distance, which uses an experimental scheme with two consecutive measurements. The three key quantifiers of a measurement, i.e., QND fidelity, readout fidelity, and projectivity, can be derived directly from the same experimental scheme. Besides, we present the relationships among these three factors. Theoretical simulation results for the dispersive readout of superconducting qubits show the validity of the proposed QND fidelity. Efficient quantification of measurement performance is of practical significance for the diagnosis, performance improvement, and design of measurement apparatuses.
