Topological classification for intersection singularities of exceptional surfaces in pseudo-Hermitian systems

التفاصيل البيبلوغرافية
العنوان: Topological classification for intersection singularities of exceptional surfaces in pseudo-Hermitian systems
المؤلفون: Jia, Hongwei, Zhang, Ruo-Yang, Hu, Jing, Xiao, Yixin, Zhu, Yifei, Chan, C. T.
سنة النشر: 2022
المجموعة: Condensed Matter
Physics (Other)
مصطلحات موضوعية: Condensed Matter - Materials Science, Physics - Optics
الوصف: Exceptional points play a pivotal role in the topology of non-Hermitian systems, and significant advances have been made in classifying exceptional points and exploring the associated phenomena. Exceptional surfaces, which are hypersurfaces of exceptional degeneracies in parameter space, can support hypersurface singularities, such as cusps, intersections and swallowtail catastrophes. Here we topologically classify the intersection singularity of exceptional surfaces for a generic pseudo-Hermitian system with parity-time symmetry. By constructing the quotient space under equivalence relations of eigenstates, we reveal that the topology of such gapless structures can be described by a non-Abelian free group on three generators. Importantly, the classification predicts a new kind of non-Hermitian gapless topological phase and can systematically explain how the exceptional surfaces and their intersections evolve under perturbations with symmetries preserved. Our work opens a new pathway for designing systems with robust topological phases, and provides inspiration for applications such as sensing and lasing which can utilize the special properties inherent in exceptional surfaces and intersections.
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2209.03068
رقم الأكسشن: edsarx.2209.03068
قاعدة البيانات: arXiv