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Related papers: Symmetry and Higher-Order Exceptional Points

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Non-Hermitian systems have attracted significant interest because of their intriguing and useful properties, including exceptional points (EPs), where eigenvalues and the corresponding eigenstates of non-Hermitian operators become…

Quantum Physics · Physics 2025-03-28 Hamed Ghaemi-Dizicheh , Shahram Dehdashti , Andreas Hanke , Ahmed Touhami , Janis Nötzel

Higher-order exceptional points (EPs) in optical structures enable ultra-sensitive responses to perturbations. However, previous investigations on higher-order EPs have predominantly focused on coupled systems, leaving their fundamental…

In non-Hermitian systems, the defective band degeneracies, so-called exceptional points (EPs), can form robust exceptional lines (ELs) in 3D momentum space in the absence of any symmetries. Here, we show that a natural orientation can be…

Optics · Physics 2022-12-13 Ruo-Yang Zhang , Xiaohan Cui , Wen-Jie Chen , Zhao-Qing Zhang , C. T. Chan

Exceptional points (EPs) are degeneracies of non-Hermitian operators where, in addition to the eigenvalues, corresponding eigenmodes become degenerate. Classical and quantum photonic systems with EPs have attracted tremendous attention due…

In non-Hermitian physics, high-order exceptional points(HOEPs) with eigenvalues and eigenvectors coalesce are known for their enhanced sensitivity to perturbations. Typically, they exhibit eigenvalue splitting that scales as…

Optics · Physics 2025-12-16 Teng Yin , Hao Zhang

Exceptional points (EPs) determine the dynamics of open quantum systems and cause also PT symmetry breaking in PT symmetric systems. From a mathematical point of view, this is caused by the fact that the phases of the wavefunctions…

Dynamical Systems · Mathematics 2014-04-30 Hichem Eleuch , Ingrid Rotter

The unique properties of exceptional point (EP) singularities, arising from non-Hermitian physics, have unlocked new possibilities for manipulating light-matter interactions. A tailored gain-loss variation, while encircling higher-order EPs…

Exceptional points (EPs) play a vital role in non-Hermitian (NH) systems, driving unique dynamical phenomena and promising innovative applications. However, the NH dynamics at EPs remains obscure due to the incomplete biorthogonal…

Quantum Physics · Physics 2025-08-06 Yan Xing , Xuedong Zhao , Hui Jing , Shi-Lei Su

Standard exceptional points (EPs) are non-Hermitian degeneracies that occur in open systems. At an EP, the Taylor series expansion becomes singular and fails to converge -- a feature that was exploited for several applications. Here, we…

Applied Physics · Physics 2021-03-25 M. Sakhdari , M. Hajizadegan , Q. Zhong , D. N. Christodoulides , R. El-Ganainy , P. -Y. Chen

Exceptional points (EPs), the degeneracy point of non-Hermitian systems, have recently attracted great attention after its ability to greatly enhance the sensitivity of micro-cavities is demonstrated experimentally. Unlike the usual…

Quantum Physics · Physics 2021-08-04 Geng-Li Zhang , Di Liu , Xi-Ming Wang , Man-Hong Yung

Exceptional points (EPs) are non-Hermitian spectral degeneracies marking a simultaneous coalescence of eigenvalues and eigenvectors. Despite the fact that multiband $n$-fold EPs (EP$n$s) generically emerge as special points on manifolds of…

Optics · Physics 2026-03-16 Anton Montag , Jordan Isaacs , Marcus Stålhammar , Flore K. Kunst

Non-Hermitian degeneracies are classified as defective and nondefective exceptional points~(EP). While in defective EPs, both eigenvalues and eigenenergies coalesce, nondefective EPs are characterized merely by the occurrence of…

Quantum Physics · Physics 2023-01-03 Sharareh Sayyad

The fascinating realm of non-Hermitian physics with the interplay of parity (P) and time-reversal (T) symmetry has been witnessing immense attention in exploring unconventional physics at Exceptional Point (EP) singularities. Particularly,…

Optics · Physics 2024-05-20 Dinesh Beniwal , Arnab Laha , Adam Miranowicz , Somnath Ghosh

Exceptional points (EPs) are spectral defects displayed by non-Hermitian systems in which multiple degenerate eigenvalues share a single eigenvector. This distinctive feature makes systems exhibiting EPs more sensitive to external…

Quantum Physics · Physics 2025-12-11 Subhajyoti Bid , Henning Schomerus

Non-Hermitian systems and their topological singularities, such as exceptional points (EPs), lines, and surfaces, have recently attracted intense interest. The investigation of these exceptional constituents has led to fruitful…

Optics · Physics 2024-08-08 Liang Fang , Kai Bai , Cheng Guo , Tian-Rui Liu , Jia-Zheng Li , Meng Xiao

Exceptional points (EPs) are special singularities of non-Hermitian Hamiltonians. At an EP, two or more eigenvalues and the corresponding eigenstates coalesce. Recently, EP-based optical gyroscope near an EP was extensively investigated to…

Quantum physics can be extended into the complex domain by considering non-Hermitian Hamiltonians that are $\mathcal{PT}$-symmetric. These exhibit exceptional points (EPs) where the eigenspectrum changes from purely real to purely imaginary…

Quantum Physics · Physics 2025-06-23 Jia-Jia Wang , Yu-Hong He , Chang-Geng Liao , Rong-Xin Chen , Jacob A. Dunningham

Exceptional points (EPs) in non-Hermitian photonic systems have attracted considerable research interest due to their singular eigenvalue topology and associated anomalous physical phenomena. These properties enable diverse applications…

Optics · Physics 2025-10-17 Kaiyuan Wang , Qi Jie Wang , Matthew R. Foreman , Yu Luo

Exceptional points (EPs), arising in non-Hermitian systems, have garnered significant attention in recent years, enabling advancements in sensing, wave manipulation, and mode selectivity. However, their role in quantum systems, particularly…

Quantum Physics · Physics 2026-01-21 Chenghe Yu , Mingsheng Tian , Ningxin Kong , Matteo Fadel , Xinyao Huang , Qiongyi He

The appearance of topological singularities, namely exceptional points (EPs) is an intriguing feature of parameter-dependent open quantum or wave systems. EPs are the special type of nonHermitian degeneracies where two (or more) eigenstates…

Quantum Physics · Physics 2018-05-18 Sayan Bhattacherjee , Arnab Laha , Somnath Ghosh