The subthreshold issue of fusion-based quantum computing

Quantum Physics arXiv:2606.28490 (quant-ph) [Submitted on 26 Jun 2026] Title:The subthreshold issue of fusion-based quantum computing Authors:Matthias C. Löbl, Love A. M. Pettersson, Jan Dragašević, Susan X. Chen, Oliver A. D. Sandberg View a PDF of the paper titled The subthreshold issue of fusion-based quantum computing, by Matthias C. L\"obl and 4 other authors View PDF HTML (experimental) Abstract:Fusion-based quantum architectures are the leading approach to photonic quantum computing. However, the sub-threshold regime, where logical error rates must reach the levels required by useful applications, has received little attention. We show that in this regime, fusion failure imposes a noise floor on the logical error rate that prevents all-linear-optics architectures from reaching the required rates at low overhead. For fusion-based architectures using quantum emitter spins, we show that the noise floor is reduced by orders of magnitude at a lower overhead. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2606.28490 [quant-ph] (or arXiv:2606.28490v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2606.28490 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Matthias Christian Löbl [view email] [v1] Fri, 26 Jun 2026 18:00:02 UTC (426 KB) Full-text links: Access Paper: View a PDF of the paper titled The subthreshold issue of fusion-based quantum computing, by Matthias C. L\"obl and 4 other authorsView PDFHTML (experimental)TeX Source view license Ancillary-file links: Ancillary files (details): FBQC_reference_thresholds.py Current browse context: quant-ph new | recent | 2026-06 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?)