Robust Lindbladian Estimation for Quantum Dynamics

Fuente: arXiv
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Hauptverfasser: Liu, Yinchen, Seddon, James R., Kohler, Tamara, Onorati, Emilio, Cubitt, Toby S.
Format: Preprint
Veröffentlicht: 2025
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author Liu, Yinchen
Seddon, James R.
Kohler, Tamara
Onorati, Emilio
Cubitt, Toby S.
author_facet Liu, Yinchen
Seddon, James R.
Kohler, Tamara
Onorati, Emilio
Cubitt, Toby S.
contents We revisit the problem of fitting Lindbladian models to the outputs of quantum process tomography. A sequence of prior theoretical works approached the problem by considering whether there exists a Lindbladian generator close to a matrix logarithm of the tomographically estimated transfer matrix. This technique must take into account the non-uniqueness of the matrix logarithm, so that in general multiple branches of the logarithm must be checked. In contrast, all practical demonstrations of Lindbladian fitting on real experimental data have to our knowledge eschewed logarithm search, instead adopting direct numerical optimisation or ad-hoc approaches tailored to a particular experimental realisation. In our work, we introduce algorithmic improvements to logarithm search, demonstrating that it can be applied in practice to settings relevant for current quantum computing hardware. We additionally augment the task of Lindbladian fitting with techniques from gate set tomography to improve robustness against state preparation and measurement (SPAM) errors, which can otherwise obfuscate estimates of the model underlying the process of interest. We benchmark our techniques extensively using simulated tomographic data employing a range of realistic error models, before demonstrating their application to tomographic data collected from real superconducting-qubit hardware.
format Preprint
id arxiv_https___arxiv_org_abs_2507_07912
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Robust Lindbladian Estimation for Quantum Dynamics
Liu, Yinchen
Seddon, James R.
Kohler, Tamara
Onorati, Emilio
Cubitt, Toby S.
Quantum Physics
Computational Physics
We revisit the problem of fitting Lindbladian models to the outputs of quantum process tomography. A sequence of prior theoretical works approached the problem by considering whether there exists a Lindbladian generator close to a matrix logarithm of the tomographically estimated transfer matrix. This technique must take into account the non-uniqueness of the matrix logarithm, so that in general multiple branches of the logarithm must be checked. In contrast, all practical demonstrations of Lindbladian fitting on real experimental data have to our knowledge eschewed logarithm search, instead adopting direct numerical optimisation or ad-hoc approaches tailored to a particular experimental realisation. In our work, we introduce algorithmic improvements to logarithm search, demonstrating that it can be applied in practice to settings relevant for current quantum computing hardware. We additionally augment the task of Lindbladian fitting with techniques from gate set tomography to improve robustness against state preparation and measurement (SPAM) errors, which can otherwise obfuscate estimates of the model underlying the process of interest. We benchmark our techniques extensively using simulated tomographic data employing a range of realistic error models, before demonstrating their application to tomographic data collected from real superconducting-qubit hardware.
title Robust Lindbladian Estimation for Quantum Dynamics
topic Quantum Physics
Computational Physics
url https://arxiv.org/abs/2507.07912