Symmetry-Engineered Multiple Bulk-Boundary Correspondences and Anomalous Modes in a Non-Hermitian Creutz Ladder
Abstract
The synergy between non-Hermiticity and topology makes the bulk-boundary correspondence (BBC) highly elusive. Here we study a non-Hermitian Creutz ladder incorporating both gain-loss and nonreciprocity, and construct multiple BBCs involving scale-free, normal, and anomalous skin modes, as well as topological zero- energy modes. We characterize the skin effect induced by the parity-time (PT) phase transition through an average winding number, thereby formulating a PT-related BBC. Furthermore, a hidden chiral symmetry ensures that topological phase transitions can be reliably detected via a Z 2 invariant. Although the gain-loss breaks the standalone P symmetry, it preserves the combined PT symmetry, allowing a modified Z 2 invariant to sustain the topological BBC. Notably, sublattice symmetry facilitates the precise analytical determination of non-Bloch spectra. Leveraging this, we introduce a hybrid spectral winding that encodes the localization (or delocalization) characteristics of two counterintuitive bulk modes coexisting with normal skin modes, thus defining a non-Hermitian BBC. One of these modes exhibits exponential boundary accumulation in a direction opposite to the nonreciprocity, while the other manifests as an anomalous surge of Bloch-wave states within the nonreciprocal lattice. These results reveal a series of unexpected phenomena governed by underlying symmetry, significantly broadening our fundamental understanding of the BBC mechanism in non-Hermitian topological systems.
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BibTeX
@misc{li2026symmetryengineered,
title = {{Symmetry-Engineered Multiple Bulk-Boundary Correspondences and Anomalous Modes in a Non-Hermitian Creutz Ladder}},
author = {Xin Li and TongYi Li and JingYu Peng and Yu Wang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.00954},
eprint = {2605.00954},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.00954},
}
RIS
TY - UNPB
TI - Symmetry-Engineered Multiple Bulk-Boundary Correspondences and Anomalous Modes in a Non-Hermitian Creutz Ladder
AU - Xin Li
AU - TongYi Li
AU - JingYu Peng
AU - Yu Wang
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2605.00954
UR - https://arxiv.org/abs/2605.00954
AB - The synergy between non-Hermiticity and topology makes the bulk-boundary correspondence (BBC) highly elusive. Here we study a non-Hermitian Creutz ladder incorporating both gain-loss and nonreciprocity, and construct multiple BBCs involving scale-free, normal, and anomalous skin modes, as well as topological zero- energy modes. We characterize the skin effect induced by the parity-time (PT) phase transition through an average winding number, thereby formulating a PT-related BBC. Furthermore, a hidden chiral symmetry ensures that topological phase transitions can be reliably detected via a Z 2 invariant. Although the gain-loss breaks the standalone P symmetry, it preserves the combined PT symmetry, allowing a modified Z 2 invariant to sustain the topological BBC. Notably, sublattice symmetry facilitates the precise analytical determination of non-Bloch spectra. Leveraging this, we introduce a hybrid spectral winding that encodes the localization (or delocalization) characteristics of two counterintuitive bulk modes coexisting with normal skin modes, thus defining a non-Hermitian BBC. One of these modes exhibits exponential boundary accumulation in a direction opposite to the nonreciprocity, while the other manifests as an anomalous surge of Bloch-wave states within the nonreciprocal lattice. These results reveal a series of unexpected phenomena governed by underlying symmetry, significantly broadening our fundamental understanding of the BBC mechanism in non-Hermitian topological systems.
ER -