Interaction-Enabled Bulk-Boundary Correspondence without a Global Band Gap
Abstract
A challenge of growing interest is how to make topology observable when conventional gap-based frameworks no longer suffice. In bulk-edge correspondence, this challenge arises when the global band gap closes and localized boundary modes disappear, even though the bulk topology remains intact. Here we show that interactions unlock a novel emergent boundary response from this spectrally hidden topology without reopening the global band gap. These interaction-induced excitations originate from a bulk-band minimum, yet reconstruct the characteristic boundary channels of a gapped topological parent sharing the same Bloch eigenspaces. We establish this interaction-enabled bulk-boundary correspondence for first- and higher-order topology in one- and two-dimensional bosonic lattices, respectively, and identify a general compatibility principle governing its emergence. Our results extend bulk-boundary correspondence beyond its conventional spectral manifestation, with experimental prospects in cold-atom and photonic platforms.
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BibTeX
@misc{ding2026interactionenabled,
title = {{Interaction-Enabled Bulk-Boundary Correspondence without a Global Band Gap}},
author = {Cong Ding and Xuzhen Cao and Zhifu Shi and Yuqing Li and Ying Hu},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.01873},
eprint = {2611.01873},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.01873},
}
RIS
TY - UNPB
TI - Interaction-Enabled Bulk-Boundary Correspondence without a Global Band Gap
AU - Cong Ding
AU - Xuzhen Cao
AU - Zhifu Shi
AU - Yuqing Li
AU - Ying Hu
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.01873
UR - https://arxiv.org/abs/2611.01873
AB - A challenge of growing interest is how to make topology observable when conventional gap-based frameworks no longer suffice. In bulk-edge correspondence, this challenge arises when the global band gap closes and localized boundary modes disappear, even though the bulk topology remains intact. Here we show that interactions unlock a novel emergent boundary response from this spectrally hidden topology without reopening the global band gap. These interaction-induced excitations originate from a bulk-band minimum, yet reconstruct the characteristic boundary channels of a gapped topological parent sharing the same Bloch eigenspaces. We establish this interaction-enabled bulk-boundary correspondence for first- and higher-order topology in one- and two-dimensional bosonic lattices, respectively, and identify a general compatibility principle governing its emergence. Our results extend bulk-boundary correspondence beyond its conventional spectral manifestation, with experimental prospects in cold-atom and photonic platforms.
ER -