Work

Surface-Code Thresholds and Qubit Footprints in Shuttling-Based Spin-Qubit Railways

Year: 2026

Type: preprint

Abstract: We present a fault-tolerant mapping of rotated surface codes onto a $2\times N$ silicon spin-qubit railway architecture, utilizing electron shuttling to resolve the wiring fan-out bottleneck. Employing circuit-level noise modeling, we evaluate threshold performances across various noise biases. We demonstrate that shuttling check qubits instead of data qubits fundamentally improves system thresholds. Crucially, under a noise model biased towards dephasing for spin-qubit shuttling, the non-CSS XZZX surface code outperforms standard CSS variants. By tailoring the topological code to this specific inherent bias, we show that the Megaquop footprint is achievable with a distance 7 code requiring a $p = 10^{-3}$ physical error rate, highlighting a pathway for substantial hardware reductions in early fault-tolerant quantum processors.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2605.05881

Authors: Moncy, Arun John, Dastbasteh, Reza, Martinez, Josu Etxezarreta, Nagai, Ryo, Crespo, Pedro M., Mertig, Normann, Smith, Charles, Otxoa, Ruben M.

Institutions: Donostia International Physics Center, Universidad de Navarra, Hitachi (Japan)

Topic: Quantum Computing Algorithms and Architecture

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: green

Funder: European Commission

OpenAlex ID: W7160648581

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