Decision Kernels for Quantum Error Mitigation: Why Accuracy Gains Need Not Improve Downstream Decisions

Quantum Physics arXiv:2607.02888 (quant-ph) [Submitted on 3 Jul 2026] Title:Decision Kernels for Quantum Error Mitigation: Why Accuracy Gains Need Not Improve Downstream Decisions Authors:Vicenzo Scavino View a PDF of the paper titled Decision Kernels for Quantum Error Mitigation: Why Accuracy Gains Need Not Improve Downstream Decisions, by Vicenzo Scavino View PDF HTML (experimental) Abstract:Quantum error mitigation (QEM) is usually benchmarked by expectation-value accuracy, but many near-term workflows use those values only to make downstream choices such as argmin selection, ranking, top-k filtering, optimizer-step acceptance, or phase labeling. This creates a structural mismatch: accuracy is measured in the ambient landscape space, whereas shift-invariant decisions depend only on gaps. We develop a quotient-space theory of finite-shot QEM for downstream decisions. The minimal decision-complete object is the residual gap law; in Gaussian finite-shot regimes it is summarized by effective margins and a decision kernel. The QEM-specific point is that this kernel is not free: it is the pullback of shared physical device noise through the mitigation map. We prove quotient factorization, gap-law minimality, a marginal no-go theorem, a QEM pullback theorem, Gaussian decision-risk formulas, and a fixed-allocation shot-level converse. Finite-shot Qiskit Aer simulations demonstrate the predicted divergence in the evaluated regimes. Clifford-data regression can be decision-flat while improving mean-squared error, and probabilistic error cancellation can improve accuracy while worsening decision risk through sampling overhead. Decision-aware selection modestly reduces static held-out failure relative to accuracy-based selection, often by retaining Raw, but the dynamic success target is not reached. Pre-registered stress tests under a calibrated device-noise model and on a hardware micro-cell probe robustness beyond these regimes. The operational implication in the evaluated regimes is to select QEM methods through residual gap geometry, not from expectation-value accuracy alone. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2607.02888 [quant-ph] (or arXiv:2607.02888v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2607.02888 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Vicenzo Scavino Alfaro [view email] [v1] Fri, 3 Jul 2026 02:35:57 UTC (105 KB) Full-text links: Access Paper: View a PDF of the paper titled Decision Kernels for Quantum Error Mitigation: Why Accuracy Gains Need Not Improve Downstream Decisions, by Vicenzo ScavinoView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-07 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?) 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?)