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Related papers: Zero Indirect Band Gap in Non-Hermitian Systems

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The interplay between band topology and material nonlinearity gives rise to a variety of novel phenomena, such as topological solitons and nonlinearity-induced topological phase transitions. However, most previous studies fall within the…

Mesoscale and Nanoscale Physics · Physics 2025-10-21 Junyao Wu , Rui-Chang Shen , Li Zhang , Fujia Chen , Bingbing Wang , Hongsheng Chen , Yihao Yang , Haoran Xue

We numerically study topological effects of electromagnetic (EM) waves in a two-dimensional (2D) non-Hermitian photonic crystal (PhC) composed of lossy magneto-optical materials. In this system, not only the EM wavefunctions but also the…

Optics · Physics 2026-04-28 Huyen Thanh Phan , Katsunori Wakabayashi

Non-Hermitian point gap (NHPG) is a unique phenomenon in non-Hermitian systems and induces non-Hermitian skin effect (NHSE). In photonic crystals, NHPG and the NHSE have previously been explored mainly through material loss, where the…

Topological phases of matter commonly feature protected states at their boundaries. Transferring this protection to time-metamaterials is extremely challenging, as it requires the generation of an abrupt interface between two topologically…

Symmetry-protected ideal flat bands in one-dimensional (1D) Hermitian lattices are populated by compact localized states (CLS) - a special class of localization with wavefunctions confined within a small region. In this work, we discover…

Quantum Physics · Physics 2025-12-24 Xulong Wang , Dongyi Wang , Congwei Lu , Ruo-Yang Zhang , Ching Hua Lee , Kun Ding , Guancong Ma

The study of topological states has developed rapidly in electric circuits, which permits flexible fabrications of non-Hermitian systems by introducing non-Hermitian terms. Here, nonreciprocal coupling terms are realized by utilizing a…

Mesoscale and Nanoscale Physics · Physics 2023-10-17 Bin Liu , Yang Li , Bin Yang , Xiaopeng Shen , Yuting Yang , Zhi Hong Hang , Motohiko Ezawa

The non-Hermitian skin effect is an iconic phenomenon characterized by the aggregation of eigenstates near the system boundaries in non-Hermitian systems. While extensively studied in one dimension, understanding the skin effect and…

Mesoscale and Nanoscale Physics · Physics 2025-01-20 Haiping Hu

For non-Hermitian quantum models, the dynamics is apparently not reflected by the static properties, e.g., the complex energy spectrum, because of the nonorthogonality of the right eigenvectors, the nonunitarity of the time evolution, the…

Quantum Physics · Physics 2021-01-12 Li-Jun Lang , Yijiao Weng , Yunhui Zhang , Enhong Cheng , Qixia Liang

Recently, many novel and exotic phases have been proposed by considering the role of topology in non-Hermitian systems, and their emergent properties are of wide current interest. In this work we propose the non-Hermitian generalization of…

Mesoscale and Nanoscale Physics · Physics 2021-10-12 Ayan Banerjee , Awadhesh Narayan

Nonreciprocal nonhermitian systems provide an unconventional localization mechanism of topological zero modes via the nonhermitian skin effect. While fundamental theoretical characterizations of this effect involve the biorthogonal system…

Mesoscale and Nanoscale Physics · Physics 2020-01-22 Henning Schomerus

We demonstrate that the non-Hermitian parity-time (PT) symmetric interfaces formed between amplifying and lossy crystals support dissipationless edge states. These PT edge states exhibit gapless spectra in the complex band structure…

Mesoscale and Nanoscale Physics · Physics 2018-10-24 Xiang Ni , Daria Smirnova , Alexander Poddubny , Daniel Leykam , Yidong Chong , Alexander B. Khanikaev

The interplay of topology and non-Hermiticity has led to diverse, exciting manifestations in a plethora of systems. In this work, we systematically investigate the role of non-Hermiticity in the Chern insulating Haldane model on a dice…

Quantum Physics · Physics 2023-04-05 Ronika Sarkar , Arka Bandyopadhyay , Awadhesh Narayan

Non-Hermitian systems give rise to distinct topological phenomena, yet their manifestations at temporal interfaces characterized by abrupt changes in system parameters remain largely unex plored. Upon an abrupt alteration of the Hamiltonian…

Parity-time ($\mathcal{PT}$) symmetry plays an important role both in non-Hermitian and topological systems. In non-Hermitian systems $\mathcal{PT}$ symmetry can lead to an entirely real energy spectrum, while in topological systems…

Mesoscale and Nanoscale Physics · Physics 2019-12-18 W. B. Rui , Moritz M. Hirschmann , Andreas P. Schnyder

We describe a diagrammatic technique for non-Hermitian fermionic systems that is applicable in the steady state, and which allows addressing correlations effects by systematic expansion. Applying this method to exceptional points or rings,…

Mesoscale and Nanoscale Physics · Physics 2020-01-29 Johan Carlström

The non-Hermitian skin effect is a distinctive phenomenon in non-Hermitian systems, which manifests as the anomalous localization of bulk states at the boundary. To understand the physical origin of the non-Hermitian skin effect, a bulk…

Quantum Physics · Physics 2024-03-06 Tuo Wan , Kai Zhang , Junkai Li , Zhesen Yang , Zhaoju Yang

Real-valued band structures are foundational to analyzing periodic systems within the Hermitian description and have been experimentally well-established over recent decades. In contrast, non-Hermitian systems exhibit complex band…

Quantum Physics · Physics 2025-10-24 Jia-Xin Zhong , Jing Lin , Kai Chen , Jing Lu , Kun Ding , Yun Jing

The traditional bulk-boundary correspondence assuring robust gapless modes at the edges and surfaces of insulating and nodal topological materials gets masked in non-Hermitian (NH) systems by the skin effect, manifesting an accumulation of…

Mesoscale and Nanoscale Physics · Physics 2022-07-14 Archisman Panigrahi , Roderich Moessner , Bitan Roy

The non-Hermitian skin effect refers to the accumulation of eigenstates near the boundary in open boundary lattice models, which can be systematically characterized using the non-Bloch band theory. Here, we apply the non-Bloch band theory…

Quantum Physics · Physics 2024-09-11 Bo Li , He-Ran Wang , Fei Song , Zhong Wang

The dynamical and topological properties of non-Hermitian systems have attracted great attention in recent years. In this work, we establish an intrinsic connection between two classes of intriguing phenomena -- topological phases and…

Quantum Physics · Physics 2021-06-18 Longwen Zhou , Qianqian Du