Floquet breaking of stroboscopic chiral symmetry in a non-Hermitian higher-order topological insulator
Floquet breaking of stroboscopic chiral symmetry in a non-Hermitian higher-order topological insulator
Minglin Li1
作者信息
- 1. school of mechanical engineering and automation, fuzhou university
- 折叠
摘要
Instantaneous chiral symmetry is conventionally carried over to the stroboscopic Floquet evolution operator. We show that this assumption fails for a non-Hermitian higher-order topological insulator driven by a circularly polarized field. Working from theBenalcazar-Bernevig-Hughes model, we classify all momentum-independent, on-site, linear, anti-Hermitian perturbations compatible with inversion and chiral symmetry. Only \(i\gamma\Gamma_4\) preserves the reciprocal non-Bloch structure, keeping the generalized Brillouin zone on the unit torus. A circular drive generates a chiral-even first-order Magnus correction \(\propto [H_x,H_y]\), which breaks \(SUS=U^{-1}\), whereas a time-reflection-symmetric linear drive preserves it. Inversion-protected corner modes remain localized throughout. These results show that instantaneous symmetry of a periodically drivennon-Hermitian Hamiltonian does not uniquely determine the symmetry of its Floquet evolution operator.
Abstract
Instantaneous chiral symmetry is conventionally carried over to the stroboscopic Floquet evolution operator. We show that this assumption fails for a non-Hermitian higher-order topological insulator driven by a circularly polarized field. Working from theBenalcazar-Bernevig-Hughes model, we classify all momentum-independent, on-site, linear, anti-Hermitian perturbations compatible with inversion and chiral symmetry. Only \(i\gamma\Gamma_4\) preserves the reciprocal non-Bloch structure, keeping the generalized Brillouin zone on the unit torus. A circular drive generates a chiral-even first-order Magnus correction \(\propto [H_x,H_y]\), which breaks \(SUS=U^{-1}\), whereas a time-reflection-symmetric linear drive preserves it. Inversion-protected corner modes remain localized throughout. These results show that instantaneous symmetry of a periodically drivennon-Hermitian Hamiltonian does not uniquely determine the symmetry of its Floquet evolution operator.关键词
Floquet topological phases/Non-Hermitian topological systems/Higher-order topological insulators/Chiral symmetry breaking/Non-Bloch bulk-boundary correspondence/Topolectrical circuitsKey words
Floquet topological phases/Non-Hermitian topological systems/Higher-order topological insulators/Chiral symmetry breaking/Non-Bloch bulk-boundary correspondence/Topolectrical circuits引用本文复制引用
Minglin Li.Floquet breaking of stroboscopic chiral symmetry in a non-Hermitian higher-order topological insulator[EB/OL].(2026-09-28)[2026-10-01].https://chinaxiv.org/abs/202609.00505.学科分类
物理学
