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Related papers: Exceptional Topological Insulators

200 papers

Topological insulators are solid state systems of independent electrons for which the Fermi level lies in a mobility gap, but the Fermi projection is nevertheless topologically non-trivial, namely it cannot be deformed into that of a normal…

Mathematical Physics · Physics 2016-10-27 Hermann Schulz-Baldes

Non-Hermitian systems hosting exceptional points (EPs) exhibit signal enhancement and unconventional mode dynamics. Going beyond isolated EPs, here we report on the existence of exceptional rings (ERs) in planar optical resonators with…

Non-Hermitian skin-edge states emerge only at one edge in one-dimensional nonreciprocal chains, where all states are localized at the edge irrespective of eigenvalues. The bulk topological number is the winding number associated with the…

Mesoscale and Nanoscale Physics · Physics 2019-05-10 Motohiko Ezawa

Exceptional bound (EB) states represent an unique new class of robust bound states protected by the defectiveness of non-Hermitian exceptional points. Conceptually distinct from the more well-known topological states and non-Hermitian skin…

Quantum Physics · Physics 2024-07-02 Deyuan Zou , Tian Chen , Haiyu Meng , Yee Sin Ang , Xiangdong Zhang , Ching Hua Lee

In this work we study many-body 'steady states' that arise in the non-Hermitian generalisation of the non-interacting Su-Schrieffer-Heeger model at a finite density of fermions. We find that the hitherto known phase diagrams for this…

Mesoscale and Nanoscale Physics · Physics 2022-05-17 Ayan Banerjee , Suraj S. Hegde , Adhip Agarwala , Awadhesh Narayan

We establish non-Hermitian topological mechanics in one dimensional (1D) and two dimensional (2D) lattices consisting of mass points connected by meta-beams that lead to odd elasticity. Extended from the "non-Hermitian skin effect" in 1D…

Soft Condensed Matter · Physics 2020-05-19 Di Zhou , Junyi Zhang

Topological insulators as new type of quantum matter materials are characterized by a full insulating gap in the bulk and gapless edge/surface states which are protected by time-reversal symmetry. We propose the interference patterns caused…

Mesoscale and Nanoscale Physics · Physics 2013-06-10 Jing Wang , Bang-Fen Zhu

We show that the bulk-boundary correspondence for topological insulators can be modified in the presence of non-Hermiticity. We consider a one-dimensional tight-binding model with gain and loss as well as long-range hopping. The system is…

Quantum Physics · Physics 2016-04-04 Tony E. Lee

We present a generalization of free fermionic topological insulators that are composed of topological subsystems of differing dimensionality. We specifically focus on topological subsystems of nonzero co-dimension are embedded within a…

Mesoscale and Nanoscale Physics · Physics 2019-09-18 Thomas I. Tuegel , Victor Chua , Taylor L. Hughes

The classification of point gap topology in all local non-Hermitian symmetry classes has been recently established. However, many entries in the resulting periodic table have only been discussed in a formal setting and still lack a physical…

Mesoscale and Nanoscale Physics · Physics 2023-09-04 M. Michael Denner , Titus Neupert , Frank Schindler

Higher-order topological insulators (HOTI) are a novel topological phase beyond the framework of the conventional bulk-boundary correspondence. In these peculiar systems, the topologically nontrivial boundary modes are characterized by a…

Strong disorder drives conventional Hermitian systems into Anderson insulating states, suppressing all topological phases. Here, we unveil symmetry-protected, anomalous topological phases in the strong disorder limit of a non-Hermitian…

Mesoscale and Nanoscale Physics · Physics 2026-02-11 Mina Ren , Xi Shi , Haitao Jiang , Feng Liu , Hong Chen , Yong Sun

Non-Hermitian (NH) systems can display exceptional topological defects without Hermitian counterparts, exemplified by exceptional rings in NH two-dimensional systems. However, exceptional topological features associated with…

Quantum Physics · Physics 2026-01-06 Shou-Bang Yang , Pei-Rong Han , Wen Ning , Fan Wu , Zhen-Biao Yang , Shi-Biao Zheng

Band topology has been studied as a design principle of realizing robust boundary modes. Here, by exploring non-Hermitian topology, we propose a three-dimensional topological laser that amplifies surface modes. The topological surface laser…

Mesoscale and Nanoscale Physics · Physics 2022-07-27 Kazuki Sone , Yuto Ashida , Takahiro Sagawa

Topological insulators are new states of quantum matter with metallic edge/surface states. In this paper, we pointed out that there exists a new type of particle-hole symmetry-protected topological insulator - topological hierarchy…

Strongly Correlated Electrons · Physics 2015-09-23 Jing He , Chun-Li Zang , Ying Liang , Su-Peng Kou

Topological phases with insulating bulk and gapless surface or edge modes have attracted much attention because of their fundamental physics implications and potential applications in dissipationless electronics and spintronics. In this…

Materials Science · Physics 2016-05-18 Yafei Ren , Zhenhua Qiao , Qian Niu

The paradigm of classifying three-dimensional (3D) topological insulators into strong and weak ones (STI and WTI) opens the door for the discovery of various topological phases of matter protected by different symmetries and defined in…

Topological insulators (TIs) are a new quantum state of matter which have gapless surface states inside the bulk energy gap. Starting with the discovery of two dimensional TIs, the HgTe-based quantum wells, many new topological materials…

Materials Science · Physics 2012-12-03 Lukas Müchler , Frederick Casper , Binghai Yan , Stanislav Chadov , Claudia Felser

Non-Hermitian Hamiltonians can give rise to exceptional points (EPs) which have been extensively explored with nominally identical coupled resonators. Here a non-Hermitian electromechanical system is developed which hosts vibration modes…

Mesoscale and Nanoscale Physics · Physics 2019-02-06 P. Renault , H. Yamaguchi , I. Mahboob

Spectra of bulk or edges in topological insulators are often made complex by non-Hermiticity. Here, we show that symmetry protection enables entirely real spectra for both bulk and edges even in non-Hermitian topological insulators. In…

Mesoscale and Nanoscale Physics · Physics 2020-09-11 Kohei Kawabata , Masatoshi Sato