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Robust Bell Nonlocality from Gottesman-Kitaev-Preskill States

Quantum Physics 2026-01-23 v1

Abstract

Bell tests based on homodyne detection are strongly constrained in continuous-variable systems. Can Gottesman-Kitaev-Preskill (GKP) encoding turn homodyne detection into a practical tool for revealing Bell nonlocality? We consider a physically motivated model in which each party performs homodyne detection and digitizes the continuous outcome via a fixed periodic binning, corresponding to logical Pauli measurements. Within this framework, we derive a bipartite no-go: CHSH cannot be violated for Bell-pair states. Moving beyond two parties, we show that finitely squeezed GKP-encoded GHZ and W states nevertheless exhibit strong multipartite nonlocality, violating multipartite Bell inequalities with homodyne-only readout. We quantify the required squeezing thresholds and robustness to loss, providing a route toward homodyne-based Bell tests in continuous-variable systems.

Keywords

Cite

@article{arxiv.2601.16189,
  title  = {Robust Bell Nonlocality from Gottesman-Kitaev-Preskill States},
  author = {Xiaotian Yang and Santiago Zamora and Rafael Chaves and Ulrik L. Andersen and Jonatan Bohr Brask and A. de Oliveira Junior},
  journal= {arXiv preprint arXiv:2601.16189},
  year   = {2026}
}

Comments

5+11 pages, 5 figures. Comments welcome