Non-Markovian Quantum Process Tomography

Characterization protocols have so far played a central role in the development of noisy intermediate-scale quantum (NISQ) computers capable impressive feats. This trajectory is expected to continue building next generation devices—ones that can surpass classical for particular tasks—but progress characterization must keep up with complexities intricate device noise. A missing piece zoo procedures tomography, which completely describe non-Markovian dynamics over given time frame. Here, we formally introduce generalization process call tensor tomography. We detail experimental requirements, construct necessary postprocessing algorithms maximum-likelihood estimation, outline best-practice aspects accurate results, and make procedure efficient low-memory processes. The pathway diagnostics informed control correlated As an example application hardware-agnostic technique, show how its predictive be used substantially improve multitime circuit fidelities on superconducting devices. Our methods could form core carefully developed software may help hardware consistently pass fault-tolerant noise threshold.4 MoreReceived 11 August 2021Revised 22 December 2021Accepted 10 May 2022DOI:https://doi.org/10.1103/PRXQuantum.3.020344Published by American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this work maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum benchmarkingQuantum controlQuantum correlations informationQuantum Information