Non-Hermitian quantum phase transitions in the XY model induced by staggered imaginary Dzyaloshinskii--Moriya interaction
Abstract
We investigate non-Hermitian quantum phase transitions driven by staggered imaginary Dzyaloshinskii--Moriya (DM) interactions in a transverse-field XY chain. By virtue of a staggered nonunitary transformation, we exactly diagonalize the Hamiltonian. For D<1, this procedure maps the non-Hermitian model onto a standard Hermitian XY chain, allowing analytical derivation of the full phase boundaries. The parameter line D=1 forms an exceptional boundary with coalesced quasiparticle eigenvalues and eigenvectors, while the entire D>1 regime falls into the ℛ𝒯-symmetry-broken phase containing two distinct z-ferromagnetic phases. We examine common quantum-information probes and show that conventional measures, such as entanglement entropy, quantum discord, and quantum coherence, fail to capture the ℛ𝒯 symmetry-breaking transition. To address this deficiency, we propose a novel coherence measure QC̃maxLR based on ℛ𝒯 symmetry and complex-conjugate eigenpair correlations. Embedding intrinsic non-Hermitian information of left and right eigenstates, QC̃maxLR reliably identifies the ℛ𝒯 symmetry-breaking transition and accurately resolves all magnetic phase boundaries.
Related
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BibTeX
@misc{jiang2026nonhermitian,
title = {{Non-Hermitian quantum phase transitions in the XY model induced by staggered imaginary Dzyaloshinskii--Moriya interaction}},
author = {Hong Jiang and Xiang-Ping Jiang and Yan-Chao Li},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23721},
eprint = {2609.23721},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23721},
}
RIS
TY - UNPB
TI - Non-Hermitian quantum phase transitions in the XY model induced by staggered imaginary Dzyaloshinskii--Moriya interaction
AU - Hong Jiang
AU - Xiang-Ping Jiang
AU - Yan-Chao Li
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23721
UR - https://arxiv.org/abs/2609.23721
AB - We investigate non-Hermitian quantum phase transitions driven by staggered imaginary Dzyaloshinskii--Moriya (DM) interactions in a transverse-field XY chain. By virtue of a staggered nonunitary transformation, we exactly diagonalize the Hamiltonian. For D<1, this procedure maps the non-Hermitian model onto a standard Hermitian XY chain, allowing analytical derivation of the full phase boundaries. The parameter line D=1 forms an exceptional boundary with coalesced quasiparticle eigenvalues and eigenvectors, while the entire D>1 regime falls into the ℛ𝒯-symmetry-broken phase containing two distinct z-ferromagnetic phases. We examine common quantum-information probes and show that conventional measures, such as entanglement entropy, quantum discord, and quantum coherence, fail to capture the ℛ𝒯 symmetry-breaking transition. To address this deficiency, we propose a novel coherence measure QC̃_max^LR based on ℛ𝒯 symmetry and complex-conjugate eigenpair correlations. Embedding intrinsic non-Hermitian information of left and right eigenstates, QC̃_max^LR reliably identifies the ℛ𝒯 symmetry-breaking transition and accurately resolves all magnetic phase boundaries.
ER -