arXiv 2103.136112021-03-25quant-ph

存在杂散量子比特间耦合的层析成像

Tomography in the presence of stray inter-qubit coupling

Tanay Roy, Ziqian Li, Eliot Kapit, David I. Schuster

备注：: 7 pages, 4 figures, Supplementary information 9 pages, 6 figures

摘要：

断层扫描是量子计算不可或缺的一部分，因为它可以通过状态重建来诊断量子过程。现有的层析成像协议是基于确定各种泡利算子的期望值，这些泡利算子通常需要单量子比特旋转。然而，在现实的系统中，量子比特经常会产生某种形式的不可避免的杂散耦合，使得很难独立于其伙伴来操纵一个量子比特。因此，应用于这些系统的标准协议导致真实量子态的不忠实再现。我们已经开发了一种称为耦合补偿层析成像的协议，该协议可以完全在软件中校正由于寄生耦合引起的误差，并准确地确定量子态。我们证明了我们的计划的性能上的两个transmon量子位始终开启$\textit{ZZ}$耦合的系统。我们的技术是一种通用的层析成像工具，可以应用于具有不同类型的杂散量子位间耦合的大型系统，并且便于使用任意层析成像脉冲甚至非正交旋转轴。

英文摘要：

Tomography is an indispensable part of quantum computation as it enables diagnosis of a quantum process through state reconstruction. Existing tomographic protocols are based on determining expectation values of various Pauli operators which typically require single-qubit rotations. However, in realistic systems, qubits often develop some form of unavoidable stray coupling making it difficult to manipulate one qubit independent of its partners. Consequently, standard protocols applied to those systems result in unfaithful reproduction of the true quantum state. We have developed a protocol, called coupling compensated tomography, that can correct for errors due to parasitic couplings completely in software and accurately determine the quantum state. We demonstrate the performance of our scheme on a system of two transmon qubits with always-on $\textit{ZZ}$ coupling. Our technique is a generic tomography tool that can be applied to large systems with different types of stray inter-qubit couplings and facilitates the use of arbitrary tomography pulses and even non-orthogonal axes of rotation.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

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