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Efficient $n$-qubit entangling operations via a superconducting quantum router

arXiv Quantum Physics
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⚡ Quantum Brief
Researchers led by Xuntao Wu demonstrated a superconducting quantum router enabling efficient n-qubit entangling operations, addressing scalability limits in near-term quantum processors. The breakthrough reduces circuit depth and mitigates decoherence errors. Building on their 2024 work, the team expanded a reconfigurable router architecture to execute programmable multi-qubit gates, achieving faster entangled state preparation with high fidelity. This marks a shift from traditional one- and two-qubit gate reliance. The study successfully implemented complex gates like two-qubit controlled-Z and three-qubit Fredkin/Toffoli gates using model-free reinforcement learning, optimizing gate performance without pre-defined models. The high-connectivity router design suggests feasibility for even higher-order n-qubit gates, potentially unlocking more efficient implementations of advanced quantum algorithms like Shor’s or Grover’s. This approach offers a practical path to scalable quantum computation by combining hardware innovation with AI-driven optimization, reducing error accumulation in deep circuits.
Efficient $n$-qubit entangling operations via a superconducting quantum router

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Quantum Physics arXiv:2604.15432 (quant-ph) [Submitted on 16 Apr 2026] Title:Efficient $n$-qubit entangling operations via a superconducting quantum router Authors:Xuntao Wu, Haoxiong Yan, Gustav Andersson, Alexander Anferov, Christopher R. Conner, Yash J. Joshi, Bayan Karimi, Amber M. King, Shiheng Li, Howard L. Malc, Jacob M. Miller, Harsh Mishra, Hong Qiao, Minseok Ryu, Jian Shi, Andrew N. Cleland View a PDF of the paper titled Efficient $n$-qubit entangling operations via a superconducting quantum router, by Xuntao Wu and 14 other authors View PDF Abstract:Quantum algorithms on near-term quantum processors are typically executed using shallow quantum circuits composed of one- and two-qubit gates. However, as circuit depth and gate number increase, gate imperfections and qubit decoherence begin to dominate, limiting algorithmic complexity. An alternative approach is to explore gates involving more than two qubits. In previous work (X. Wu et al., Physical Review X 14, 041030 (2024)), we demonstrated a new superconducting qubit architecture with user-selectable two-qubit interactions via a reconfigurable router, used to connect pairs of qubits. Here, we leverage this novel architecture to realize programmable and efficient multi-qubit operations involving more than two qubits, resulting in faster preparation of multi-qubit entangled states with good fidelities. We also successfully apply model-free reinforcement learning to perform multi-qubit gates, including training a two-qubit controlled-Z gate as well as three-qubit controlled-SWAP and controlled-controlled-phase (Fredkin and Toffoli) gates. Higher $n$th-order gates may also be feasible, using our high-connectivity router design. This could provide a more efficient and higher-fidelity implementation of complex quantum algorithms and a more practical approach to quantum computation. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.15432 [quant-ph] (or arXiv:2604.15432v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2604.15432 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Xuntao Wu [view email] [v1] Thu, 16 Apr 2026 18:00:04 UTC (4,641 KB) Full-text links: Access Paper: View a PDF of the paper titled Efficient $n$-qubit entangling operations via a superconducting quantum router, by Xuntao Wu and 14 other authorsView PDFTeX 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?)

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quantum-networking
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Source: arXiv Quantum Physics