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We study the influence of the antiferromagnetic order on the surface states of topological insulators. We derive an effective Hamiltonian for these states, taking into account the spatial structure of the antiferromagnetic order. We obtain…

Mesoscale and Nanoscale Physics · Physics 2024-05-14 R. S. Akzyanov , A. L. Rakhmanov

A unique feature of non-Hermitian systems is the skin effect, which is the extreme sensitivity to the boundary conditions. Here, we reveal that the skin effect originates from intrinsic non-Hermitian topology. Such a topological origin not…

Mesoscale and Nanoscale Physics · Physics 2020-03-04 Nobuyuki Okuma , Kohei Kawabata , Ken Shiozaki , Masatoshi Sato

We study the topological properties of Bose-Mott insulators in one-dimensional non-Hermitian superlattices, which may serve as effective Hamiltonians for cold atomic optical systems with either two-body loss or one-body loss. We find that…

Strongly Correlated Electrons · Physics 2020-07-29 Zhihao Xu , Shu Chen

Bulk-boundary correspondence, connecting the bulk topology and the edge states, is an essential principle of the topological phases. However, the bulk-boundary correspondence is broken down in general non-Hermitian systems. In this paper,…

Mesoscale and Nanoscale Physics · Physics 2021-02-24 Yang Cao , Yang Li , Xiaosen Yang

Point-gap topological phases of non-Hermitian systems exhibit exotic boundary states that have no counterparts in Hermitian systems. Here, we develop classification of second-order point-gap topological phases protected by reflection…

Mesoscale and Nanoscale Physics · Physics 2025-12-05 Yutaro Tanaka , Daichi Nakamura , Ryo Okugawa , Kohei Kawabata

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 examine a non-Hermitian (NH) tight-binding system comprising of two orbitals per unit cell and their electrical circuit analogues. We distinguish the PT-symmetric and non-PT symmetric cases characterised by non-reciprocal nearest…

Mesoscale and Nanoscale Physics · Physics 2024-03-11 Dipendu Halder , Ronny Thomale , Saurabh Basu

We study the one-dimensional non-Hermitian lattices with linearly varying nonreciprocal hopping, where the non-Hermitian skin effect (NHSE) is found to be dissolved gradually as the strength of nonreciprocity increases. The energy spectrum…

Quantum Physics · Physics 2024-03-27 Bo Hou , Han Xiao , Rong Lü , Qi-Bo Zeng

The generic nature of band touching points in three-dimensional band structures is at heart of the rich phenomenology, topological stability and novel Fermi arc surface states associated with Weyl semimetals. Here we report on the…

Mesoscale and Nanoscale Physics · Physics 2018-11-13 Johan Carlström , Emil J. Bergholtz

Topological characterization of non-Hermitian band structures demands more than a straightforward generalization of the Hermitian cases. Even for one-dimensional tight-binding models with nonreciprocal hopping, the appearance of point gaps…

Mesoscale and Nanoscale Physics · Physics 2021-11-18 James Bartlett , Haiping Hu , Erhai Zhao

The Hatano-Nelson model is one of the most prototypical non-Hermitian models that exhibit the intrinsic non-Hermitian topological phases and the concomitant skin effect. These phenomena unique to non-Hermitian topological systems originate…

Strongly Correlated Electrons · Physics 2023-09-19 Taozhi Guo , Kohei Kawabata , Ryota Nakai , Shinsei Ryu

Non-Hermitian topological phases bear a number of exotic properties, such as the non-Hermitian skin effect and the breakdown of conventional bulk-boundary correspondence. In this paper, we introduce an unsupervised machine learning approach…

Mesoscale and Nanoscale Physics · Physics 2021-12-16 Li-Wei Yu , Dong-Ling Deng

Non-Hermitian skin effect(NHSE) describes a unique non-Hermitian phenomenon that all eigen-modes are localized near the boundary, and has profound impact on a wide range of bulk properties. In particular, topological systems with NHSE have…

Quantum Gases · Physics 2022-11-29 Lihong Zhou , Haowei Li , Wei Yi , Xiaoling Cui

Non-Hermiticity naturally breaks down the adiabaticity and thus leads to non-Abelian behaviors in multi-band systems. Here, we study how non-Abelian properties emerge in non-Hermitian systems by considering a multi-band non-Hermitian model…

Mesoscale and Nanoscale Physics · Physics 2025-09-17 Ziyu Zhou , Zhi-Cong Xu , Li-Jun Lang

The spectral and dynamical properties of dissipative quantum systems, as modeled by a damped oscillator in the Fock space, are investigated from a topological point of view. Unlike a physical lattice system that is naturally under the open…

Quantum Physics · Physics 2021-06-02 Jian-Song Pan , Linhu Li , Jiangbin Gong

Far from being limited to a trivial generalization of their Hermitian counterparts, non-Hermitian topological phases have gained widespread interest due to their unique properties. One of the most striking non-Hermitian phenomena is the…

Mesoscale and Nanoscale Physics · Physics 2022-05-25 Kuangyin Deng , Benedetta Flebus

Quantum dots are one of the paradigmatic solid-state systems for quantum engineering, providing an outstanding tunability to explore fundamental quantum phenomena. Here we show that non-Hermitian many-body topological modes can be realized…

Mesoscale and Nanoscale Physics · Physics 2022-02-07 Timo Hyart , Jose L. Lado

The spectral properties of a non-Hermitian quasi-1D lattice in two of the possible dimerization configurations are investigated. Specifically, it focuses on a non-Hermitian diamond chain that presents a zero-energy flat band. The flat band…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 C. Martínez-Strasser , M. A. J. Herrera , A. García-Etxarri , G. Palumbo , F. K. Kunst , D. Bercioux

A unique feature of non-Hermitian (NH) systems is the NH skin effect, i.e. the edge localization of an extensive number of bulk-band eigenstates in a lattice with open or semi-infinite boundaries. Unlike extended Bloch waves in Hermitian…

Quantum Physics · Physics 2022-04-14 Stefano Longhi

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