Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler
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Quantum Physics arXiv:2604.05048 (quant-ph) [Submitted on 6 Apr 2026] Title:Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler Authors:Angela Q. Chen, Xian Wu, Sarah Strong, Stefano Poletto View a PDF of the paper titled Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler, by Angela Q. Chen and 3 other authors View PDF HTML (experimental) Abstract:Tunable couplers in superconducting qubit architectures enable strong qubit-qubit interactions for two-qubit gates while suppressing unwanted coupling during single-qubit operations. However, achieving low error rates for fast two-qubit gates remains challenging, as suppressing leakage and non-adiabatic errors typically requires specialized qubit, coupler, or pulse designs, often at the expense of an idling $ZZ=0$ condition. In this work, we demonstrate that a symmetric floating tunable coupler provides a natural platform for fast, high-fidelity adiabatic controlled-Z (CZ) gates. Its favorable energy-level structure eliminates the conventional trade-off between rapid conditional-phase accumulation and adiabatic evolution while preserving exact cancellation of residual $ZZ$ interaction at idling. This architecture exhibits intrinsic robustness to non-adiabatic transitions, even under simple flux modulation waveforms. To push performance at short gate durations, where maintaining adiabaticity becomes more challenging despite the favorable level structure, we introduce pulse-shaping techniques based on the instantaneous adiabatic factor that further suppress non-adiabatic errors. We experimentally realize a 24 ns adiabatic CZ gate with fidelity exceeding 99.9% and stable operation over several hours. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.05048 [quant-ph] (or arXiv:2604.05048v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2604.05048 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Angela Q. Chen [view email] [v1] Mon, 6 Apr 2026 18:01:14 UTC (1,088 KB) Full-text links: Access Paper: View a PDF of the paper titled Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler, by Angela Q. Chen and 3 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-04 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?)