Optimal nonlocality transfer matrix in quantum chains with translational symmetry breaking
Phys. Rev. A 114, 022206 – Published 11 August, 2026
DOI: https://doi.org/10.1103/sllr-kbjx
Abstract
We extend the nonlocality transfer matrix framework to quantum phases exhibiting spontaneous translational symmetry breaking. We show that for a broad family of these phases, the standard assumption—wherein the spatial periodicity of the transfer matrix () matches that of the ground state ()—is insufficient to capture the maximal violation of Bell-type inequalities. Instead, we establish that an optimal construction with is physically required to fully detect multipartite nonlocality in these regimes. Applying this generalized framework to the axial next-nearest-neighbor Ising model and the Kitaev-Heisenberg chain, we demonstrate that the extended nonlocality spectrum reveals multipartite nonlocality hidden by the conventional approach and provides sensitive signatures of quantum phase transitions.