Robust GHZ State Preparation via Majority-Voted Boundary Measurements
Preparing high-fidelity Greenberger-Horne-Zeilinger (GHZ) states on noisy quantum hardware remains challenging due to cumulative gate errors and decoherence. We introduce Group-Majority-Voting (Group-MV), a dynamic-circuit protocol that partitions arbitrary coupling graphs, prepares local GHZ states in parallel, and fuses them via majority-voted mid-circuit measurements. The majority vote over redundant boundary links mitigates measurement errors that would otherwise propagate through classical feedforward. We evaluate Group-MV on simulated Heavy-hex and Grid topologies for 30 through 60 qubits under a realistic noise regime. Group-MV generalizes to arbitrary GHZ sizes on arbitrary coupling topologies, achieving 2.4x higher fidelity than the Line Dynamic method while tracking the unitary baseline within 3%.
Citation
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@misc{jeanbaptiste2026260219405,
title = {Robust GHZ State Preparation via Majority-Voted Boundary Measurements},
author = {Jean-Baptiste Waring and Sébastien Le Beux and Christophe Pere},
year = {2026},
eprint = {2602.19405},
archivePrefix = {arXiv},
primaryClass = {quant-ph}
} Acknowledgements
This work was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grants programme and by the Fonds de recherche du Québec — Nature et technologies (FRQNT).