近日，中国科学院物理研究所的范桁&许凯及其研究团队取得一项新进展。经过不懈努力，他们利用矩阵积密度算子研制出层析辅助噪声量子电路模拟器。相关研究成果已于2024年9月4日在国际知名学术期刊《物理评论A》上发表。

为解决这些挑战，该研究团队采用量子过程层析成像（QPT）技术，直接捕捉实验装置的操作特性，并将其整合到使用矩阵乘积密度算符（MPDO）的数值模拟中。随后，研究人员应用QPT辅助的MPDO模拟器，探索生成含噪纠缠态的变分方法，并将结果与在Quafu云量子计算平台上进行的标准噪声数值模拟和演示进行对比。

此外，他们还研究了含噪声的最大割问题（MaxCut），以及串扰和噪声截断的影响。这项研究结果为噪声对NISQ设备的影响提供了宝贵见解，并为在复杂噪声环境中改进量子算法的设计和评估奠定了基础。

据悉，近年来，结合理想噪声假设的高效量子电路模拟依赖于张量网络模拟器，尤其是利用了矩阵乘积密度算符（MPDO）框架。然而，在真实的含噪中等规模量子（NISQ）设备上进行实验时，往往会遇到复杂的噪声特性，包括不可控因素以及特定于仪器的效应，例如串扰。

附：英文原文

Title: Tomography-assisted noisy quantum circuit simulator using matrix product density operators

Author: Wei-guo Ma, Yun-Hao Shi, Kai Xu, Heng Fan

Issue&Volume: 2024/09/04

Abstract: In recent years, efficient quantum circuit simulations incorporating ideal noise assumptions have relied on tensor network simulators, particularly leveraging the matrix product density operator (MPDO) framework. However, experiments on real noisy intermediate-scale quantum (NISQ) devices often involve complex noise profiles, encompassing uncontrollable elements and instrument-specific effects such as crosstalk. To address these challenges, we employ quantum process tomography (QPT) techniques to directly capture the operational characteristics of the experimental setup and integrate them into numerical simulations using MPDOs. Our QPT-assisted MPDO simulator is then applied to explore a variational approach for generating noisy entangled states, comparing the results with standard noise numerical simulations and demonstrations conducted on the Quafu cloud quantum computation platform. Additionally, we investigate noisy MaxCut problems, as well as the effects of crosstalk and noise truncation. Our results provide valuable insights into the impact of noise on NISQ devices and lay the foundation for enhanced design and assessment of quantum algorithms in complex noise environments.

DOI: 10.1103/PhysRevA.110.032604

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.032604