Robust Bell Nonlocality from Gottesman-Kitaev-Preskill States
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