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There have been considerable efforts devoted to the study of topological phases in certain non-Hermitian systems that possess real eigenfrequencies in the presence of gain and loss. However, it is challenging to experimentally realize such…

Mesoscale and Nanoscale Physics · Physics 2022-03-08 Shuo Liu , Shaojie Ma , Cheng Yang , Lei Zhang , Wenlong Gao , Yuan Jiang Xiang , Tie Jun Cui , Shuang Zhang

Photonic topological edge states in one-dimensional dimer chains have long been thought to be robust to structural perturbations by mapping the topological Su-Schrieffer-Heeger model of a solid-state system. However, the edge states at the…

Applied Physics · Physics 2020-07-10 Zhiwei Guo , Tengzhou Zhang , Juan Song , Haitao Jiang , Hong Chen

In this work we investigate non-Hermitian topological phase transitions using real-space edge states as a paradigmatic tool. We focus on the simplest non-Hermitian variant of the Su-Schrieffer-Hegger model, including a parameter that…

Strongly Correlated Electrons · Physics 2024-03-15 Rui Aquino , Nei Lopes , Daniel G. Barci

The on-site potentials may break the symmetry of a system, resulting in the loss of its original topology protected by the symmetry. In this work, we study the counteracting effect of non-Hermitian terms on real potentials, resulting in…

Strongly Correlated Electrons · Physics 2025-06-09 E. S. Ma , K. L. Zhang , Z. Song

It was known that for non-Hermitian topological systems due to the non-Hermitian skin effect, the bulk-edge correspondence is broken down. In this paper, by using one-dimensional Su-SchriefferHeeger model and two-dimensional (deformed)…

Mesoscale and Nanoscale Physics · Physics 2020-05-20 Can Wang , Xiao-Ran Wang , Cui-Xian Guo , Su-Peng Kou

A non-Hermitian topological insulator with real spectrum is interesting in the theory of non-Hermitian extension of topological systems. We find an experimentally realizable example of a two dimensional non-Hermitian topological insulator…

Mesoscale and Nanoscale Physics · Physics 2019-10-16 C. Yuce , H. Ramezani

We study a non-Hermitian non-Abelian topological insulator preserving $PT$ symmetry, where the non-Hermitian term represents nonreciprocal hoppings. As it increases, a spontaneous $PT$ symmetry breaking transition occurs in the perfect-flat…

Mesoscale and Nanoscale Physics · Physics 2021-10-04 Motohiko Ezawa

The effect of non-Hermiticity in band topology has sparked many discussions on non-Hermitian topological physics. It has long been known that non-Hermitian Hamiltonians can exhibit real energy spectra under the condition of parity-time…

Mesoscale and Nanoscale Physics · Physics 2024-03-20 Yang Long , Haoran Xue , Baile Zhang

We study the effect of periodic but commensurate hopping modulation on a Su-Schrieffer-Heeger (SSH) chain with an additional onsite staggered imaginary potential. Such dissipative, non-Hermitian (NH) extension amply modifies the features of…

Mesoscale and Nanoscale Physics · Physics 2024-09-06 Surajit Mandal , Satyaki Kar

We study a topological band degeneracy in non-Hermitian systems with parity-time ($PT$) and parity-particle-hole ($CP$) symmetries. In $d$-dimensional non-Hermitian systems, it is shown that $(d-1)$-dimensional exceptional surfaces can…

Mesoscale and Nanoscale Physics · Physics 2019-01-30 Ryo Okugawa , Takehito Yokoyama

In this work, we consider a tight binding lattice with two non-Hermitian impurities. The system is described by a non-Hermitian generalization of the Aubry Andre model. We show for the first time that there exists topologically nontrivial…

Quantum Physics · Physics 2015-06-24 Cem Yuce

Symmetry-protected topological phases of matter, characterized by non-trivial band topology, are spectrally gapped and show non-trivial boundary phenomena. Here, we show that scattering states when interjected by an array of periodically…

Mesoscale and Nanoscale Physics · Physics 2026-04-16 Rahul Singh , Ritajit Kundu , Arijit Kundu , Adhip Agarwala

Non-Hermiticity can vary the topology of system, induce topological phase transition, and even invalidate the conventional bulk-boundary correspondence. Here, we show the introducing of non-Hermiticity without affecting the topological…

Mesoscale and Nanoscale Physics · Physics 2019-07-30 K. L. Zhang , H. C. Wu , L. Jin , Z. Song

We address the conditions required for a $\mathbb{Z}$ topological classification in the most general form of the non-Hermitian Su-Schrieffer-Heeger (SSH) model. Any chirally-symmetric SSH model will possess a "conjugated-pseudo-Hermiticity"…

Mesoscale and Nanoscale Physics · Physics 2018-01-17 Simon Lieu

Topological phases feature robust edge states that are protected against the effects of defects and disorder. The robustness of these states presents opportunities to design technologies that are tolerant to fabrication errors and resilient…

This work delves into the energy localization in non-Hermitian systems, particularly focusing on the effects of topological defects in spherical models. We analyze the mode distribution changes in non-Hermitian Su-Schrieffer-Heeger (SSH)…

Applied Physics · Physics 2024-02-06 Xizhou Shen , Xiumei Wang , Haotian Guo , Xingping Zhou

The congregation of topological quantum and classical systems with the ideas of non-Hermitian physics has generated enormous research interest in the last few years. While the concepts associated to non-trivial topological aspects have…

Applied Physics · Physics 2021-08-27 Nitish Kumar Gupta , Arun M. Jayannavar

Photonic systems with parity-time (PT) symmetry and topology are attracting considerable attentions. In this work, topological near-zero edge states are studied in PT-symmetric photonic lattice and the results indicate that the near-zero…

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 propose a scheme to realize various non-Hermitian topological phases in a topolectrical (TE) circuit network consisting of resistors, inductors, and capacitors. These phases are characterized by topologically protected exceptional points…

Mesoscale and Nanoscale Physics · Physics 2021-02-09 S M Rafi-Ul-Islam , Zhuo Bin Siu , Mansoor B. A. Jalil