论文标题
多数设备中量子非隔离测量的平行断层扫描
Parallel tomography of quantum non-demolition measurements in multi-qubit devices
论文作者
论文摘要
QND测量的有效表征是证明和提高量子处理器的性能和可扩展性的重要组成部分。在这项工作中，我们介绍了QND测量的平行断层扫描，该测量值涉及多量量子处理器上的单量和两量读数。我们在7克IBM-Q设备上提供了层析成像协议的实验演示，该协议表征了常规量子读数的质量以及诸如奇偶校验或测量和归化方案之类的广义测量值。我们的协议重建了测量过程的CHOI矩阵，提取相关的量词 - 保真度，QND，破坏性 - 并确定限制重复QND测量设备性能的错误源。我们还展示了如何量化测量串扰并使用它来证明在多个量子位上同时读数的质量。
An efficient characterization of QND measurements is an important ingredient towards certifying and improving the performance and scalability of quantum processors. In this work, we introduce a parallel tomography of QND measurements that addresses single- and two-qubit readout on a multi-qubit quantum processor. We provide an experimental demonstration of the tomographic protocol on a 7-qubit IBM-Q device, characterizing the quality of conventional qubit readout as well as generalized measurements such as parity or measurement-and-reset schemes. Our protocol reconstructs the Choi matrices of the measurement processes, extracts relevant quantifiers -- fidelity, QND-ness, destructiveness -- and identifies sources of errors that limit the performance of the device for repeated QND measurements. We also show how to quantify measurement cross-talk and use it to certify the quality of simultaneous readout on multiple qubits.
