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Efficiently Learning Global Quantum Channels with Local Tomography

arXiv Quantum Physics
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⚡ Quantum Brief
Researchers Zidu Liu and Dominik S. Wild propose a scalable framework to reconstruct global quantum channels using only local measurements, addressing a key challenge in quantum processor characterization. The method combines local shadow tomography with convex optimization, requiring exponentially decaying correlations (measured via conditional mutual information) for efficiency. Sample complexity scales polynomially with system size and error tolerance. Numerical tests demonstrate success on 50-qubit systems under local Lindbladian evolution and noisy shallow circuits, using tensor network representations for scalability. The approach recovers critical global metrics like process fidelity, Choi state purity, and Pauli-weight-resolved process matrix elements, extending shadow tomography’s utility beyond local observables. This work bridges local measurements and global channel reconstruction, offering a practical path to scalable quantum device benchmarking.
Efficiently Learning Global Quantum Channels with Local Tomography

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Quantum Physics arXiv:2603.07037 (quant-ph) [Submitted on 7 Mar 2026] Title:Efficiently Learning Global Quantum Channels with Local Tomography Authors:Zidu Liu, Dominik S. Wild View a PDF of the paper titled Efficiently Learning Global Quantum Channels with Local Tomography, by Zidu Liu and Dominik S. Wild View PDF HTML (experimental) Abstract:Scalable characterization of quantum processors is crucial for mitigating noise and imperfections. While randomized measurement protocols enable efficient access to local observables, inferring a globally consistent description of multi-qubit processes remains challenging. Here we introduce a local-to-global reconstruction framework for one-dimensional multi-qubit states and channels. The method is efficient provided that correlations, as quantified by the conditional mutual information, decay exponentially. In particular, we prove that under this assumption, the required number of samples scales polynomially with the system size and the desired global reconstruction error. Our approach is based on combining local shadow tomography with locally optimal recovery maps obtained by convex optimization. We supplement these rigorous guarantees by studying the performance of the protocol numerically for a system evolving under a local Lindbladian and a noisy, shallow circuit. By employing a tensor networ representation, we reconstruct channels acting on up to 50 qubits and accurately recover global diagnostics such as the process fidelity, the Choi state purity, and Pauli-weight-resolved process matrix elements. Our work thus extends the powerful toolbox local shadow tomography to scalable channel characterization with access to global properties. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.07037 [quant-ph] (or arXiv:2603.07037v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.07037 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Zidu Liu [view email] [v1] Sat, 7 Mar 2026 04:54:48 UTC (450 KB) Full-text links: Access Paper: View a PDF of the paper titled Efficiently Learning Global Quantum Channels with Local Tomography, by Zidu Liu and Dominik S. WildView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-03 References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv (What is alphaXiv?) Links to Code Toggle CatalyzeX Code Finder for Papers (What is CatalyzeX?) DagsHub Toggle DagsHub (What is DagsHub?) GotitPub Toggle Gotit.pub (What is GotitPub?) Huggingface Toggle Hugging Face (What is Huggingface?) Links to Code Toggle Papers with Code (What is Papers with Code?) ScienceCast Toggle ScienceCast (What is ScienceCast?) Demos Demos Replicate Toggle Replicate (What is Replicate?) Spaces Toggle Hugging Face Spaces (What is Spaces?) Spaces Toggle TXYZ.AI (What is TXYZ.AI?) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower (What are Influence Flowers?) Core recommender toggle CORE Recommender (What is CORE?) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs. Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)

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Source: arXiv Quantum Physics