2026-10-21 · arXiv Quantum Physics
arXiv:2610.27587v1 Announce Type: new
Abstract: Universal information extracted from entanglement at a critical point is commonly associated with the long-distance properties of the bulk state, while microscopic details of a lattice bipartition are expected to be washed out under coarse graining. Counterintuitively, we show directly that such microscopic information can survive in the statistical ensemble that determines the second R\'enyi entropy and obviously change the physics there. Using quantum Monte Carlo simulations of the square-lattice $J$-$Q_3$ model at the N\'eel--valence-bond-solid (VBS) transition, we measure magnetic and dimer order parameters in the R\'enyi-2 ensemble. For a standard axis-aligned bipartition, the VBS component perpendicular to the entanglement boundary remains finite in the thermodynamic extrapolation and is inequivalent to the parallel component, while the N\'eel order vanishes. For a $45^\circ$ tilted bipartition, in contrast, the two VBS components remain equivalent within numerical accuracy. We interpret this contrast in terms of the R\'enyi twist defect: the two bipartitions have the same bulk theory but realize different microscopic defect symmetries. Our results demonstrate that lattice information invisible to the bulk continuum theory alone can remain active in the long-distance R\'enyi ensemble, providing a microscopic explanation for the strong bipartition dependence previously observed in entanglement studies of deconfined criticality.
原文链接：https://arxiv.org/abs/2610.27587
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