Towards logical entanglement creation in trivalent planar architectures

• URL: http://arxiv.org/abs/2607.15044v2
• Date: Wed, 22 Jul 2026 12:33:22 GMT
• Title: Towards logical entanglement creation in trivalent planar architectures
• Abstract summary: Low-overhead quantum error-correction schemes are essential for enabling quantum computation on registers containing multiple logical qubits.<n>Recent work has shown that a physical-qubit connectivity of degree three is sufficient to implement fault-tolerant quantum error correction.<n>We study lattice surgery in the context of such trivalent architectures and introduce scalable circuit constructions to implement it.
• Score: 0.8051523919648371
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Low-overhead quantum error-correction schemes are essential for enabling quantum computation on registers containing multiple logical qubits. For planar architectures with limited nearest-neighbor qubit connectivity, the surface code has emerged as the leading paradigm. Recent theoretical and experimental work has shown that a physical-qubit connectivity of degree three is sufficient to implement fault-tolerant quantum error correction. In this work, we study lattice surgery in the context of such trivalent architectures and introduce scalable circuit constructions to implement it. Compared with the four-valent measurement scheme, the trivalent lattice-surgery protocol reduces the required resources by $\mathcal{O}(d)$ qubits out of a total qubit count of $\mathcal{O}(d^2)$ and by $\mathcal{O}(d)$ two-qubit gates out of a total two-qubit gate count of $\mathcal{O}(d^3)$. We benchmark the logical fidelity of both lattice-surgery schemes in terms of experimentally realistic simulations targeting an implementation with a fluxonium qubit based architecture and find a potential improvement of up to $\approx25\%$ for distance-three. These results open a way for scalable planar trivalent qubit architectures to host a surface-code-based logical quantum processor.

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