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We introduce the notion of topological electronic states on random lattices in non-integer dimensions. By considering a class $D$ model on critical percolation clusters embedded in two dimensions, we demonstrate that these topological…

Mesoscale and Nanoscale Physics · Physics 2022-12-15 Moein N. Ivaki , Isac Sahlberg , Kim Pöyhönen , Teemu Ojanen

In this paper, we study the properties of two-dimensional lattices in the presence of non-Hermitian disorder. In the context of coupled mode theory, we consider random gain-loss distributions on every waveguide channel (on site disorder).…

Disordered Systems and Neural Networks · Physics 2021-03-16 A. F. Tzortzakakis , K. G. Makris , E. N. Economou

Spectral winding of complex eigenenergies represents a topological aspect unique in non-Hermitian systems, which vanishes in one-dimensional (1D) systems under the open boundary conditions (OBC). In this work, we discover a boundary…

Mesoscale and Nanoscale Physics · Physics 2023-04-18 Zuxuan Ou , Yucheng Wang , Linhu Li

Non-Hermitian (NH) systems exhibit intricate spectral topology arising from complex-valued eigenenergies, with positive/negative imaginary parts representing gain/loss. Unlike the orthogonal eigenstates of Hermitian systems, NH systems…

Mesoscale and Nanoscale Physics · Physics 2025-12-15 Jia-Xin Zhong , Jeewoo Kim , Kai Chen , Jing Lu , Kun Ding , Yun Jing

Recently, the search for topological states of matter has turned to non-Hermitian systems, which exhibit a rich variety of unique properties without Hermitian counterparts. Lattices modeled through non-Hermitian Hamiltonians appear in the…

Mesoscale and Nanoscale Physics · Physics 2019-01-21 V. M. Martinez Alvarez , J. E. Barrios Vargas , M. Berdakin , L. E. F. Foa Torres

We report the exact closed-form solutions for higher-order topological states as well as explicit energy-spectrum relationships in two-dimensional (2D) non-Hermitian multi-orbital lattices with generalized boundary conditions. These…

Recent years have seen a growing interest in topological phases beyond the standard paradigm of gapped, isolated systems. One recent direction is to explore topological features in non-hermitian systems that are commonly used as effective…

Mesoscale and Nanoscale Physics · Physics 2026-02-03 Carlos Ortega-Taberner , Maria Hermanns

Defects which appear in heterostructure junctions involving topological insulators are sources of gapless modes governing the low energy properties of the systems, as recently elucidated by Teo and Kane [Physical Review B82, 115120 (2010)].…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Ken Shiozaki , Satoshi Fujimoto

Recently, topological quantum states of non-Hermitian systems, exhibiting rich new exotic states, have attracted great attention in condensed-matter physics. As for the demonstration, most of non-Hermitian topological phenomena previously…

Mesoscale and Nanoscale Physics · Physics 2019-02-15 Huaiqiang Wang , Jiawei Ruan , Haijun Zhang

In this work we study topological properties of the one-dimensional Creutz ladder model with different non-Hermitian asymmetric hoppings and on-site imaginary potentials, and obtain phase diagrams regarding the presence and absence of an…

Quantum Physics · Physics 2022-01-14 Hui-Qiang Liang , Linhu Li

Topological defects are fundamental to the collective dynamics of non-equilibrium systems and in active matter, mediating spontaneous flows, dynamic self-organization, and emergent pattern formation. Here, we reveal critical states in…

Non-Hermitian topological systems have attracted a lot of research activities in recent times, both theoretically and experimentally, due to their unique physical properties and association with open quantum systems. We show that modular…

Quantum Physics · Physics 2026-05-29 Saubhik Sarkar , Chiranjib Mukhopadhyay , Abolfazl Bayat

We investigate non-Hermitian elastic lattices characterized by non-local feedback control interactions. In one-dimensional lattices, we show that the proportional control interactions produce complex dispersion relations characterized by…

Mesoscale and Nanoscale Physics · Physics 2020-06-24 Matheus I. N. Rosa , Massimo Ruzzene

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

The language and methods of algebraic topology, particularly homotopy theory, have been extensively used in the study of the identification, the classification and the evolution of defects. Topological methods provide the means for the…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. D. M. Kavoussanaki

This paper extends the property of interlacing of the zeros of eigenfunctions in Hermitian systems to the topological property of winding number in non-Hermitian systems. Just as the number of nodes of each eigenfunction in a self-adjoint…

Mathematical Physics · Physics 2018-01-17 Stella T. Schindler , Carl M. Bender

Lattice defects such as stacking faults may obscure electronic topological features of real materials. In fact, defects are a source of disorder that can enhance the density of states and conductivity of the bulk of the system and they…

Mesoscale and Nanoscale Physics · Physics 2022-10-05 Gabriele Naselli , Viktor Könye , Sanjib Kumar Das , G. G. N. Angilella , Anna Isaeva , Jeroen van den Brink , Cosma Fulga

The competition between non-Hermitian skin effect and Anderson localization leads to various intriguing phenomena concerning spectrums and wavefunctions. Here, we study the linear response of disordered non-Hermitian systems, which is…

Mesoscale and Nanoscale Physics · Physics 2025-02-20 Yin-Quan Huang , Yu-Min Hu , Wen-Tan Xue , Zhong Wang

We show that a non-Hermitian lattice with a disclination can host topological disclination states that are induced by on-site gain and loss. The disclination states are inherently non-Hermitian as they do not exist in the limit of zero…

Mesoscale and Nanoscale Physics · Physics 2024-06-06 Rimi Banerjee , Subhaskar Mandal , Yun Yong Terh , Shuxin Lin , Gui-Geng Liu , Baile Zhang , Y. D. Chong

There are two prominent applications of the mathematical concept of topology to the physics of materials: band topology, which classifies different topological insulators and semimetals, and topological defects that represent immutable…

Materials Science · Physics 2022-08-11 Zhi-Kang Lin , Qiang Wang , Yang Liu , Haoran Xue , Baile Zhang , Yidong Chong , Jian-Hua Jiang