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Externally controllable band gap properties of a material is crucial in designing optoelectronic devices with desirable properties on-demand. Here, a possibility of single parameter tuning of trivial to non-trivial topological band gap by…

Mesoscale and Nanoscale Physics · Physics 2020-08-17 Bikashkali Midya

We study a model consisting of a central $\mathcal{PT}$-symmetric trimer with non-Hermitian strength parameter $\gamma$ coupled to two semi-infinite Su-Schrieffer-Heeger (SSH) leads. We show the existence of two zero-energy modes, one of…

Quantum Physics · Physics 2021-12-30 Savannah Garmon , Kenichi Noba

Through the study of the Rep($D_8$) non-invertible symmetry, we show how non-invertible symmetries manifest in dynamics. By considering the effect of symmetry preserving disorder, the non-invertible symmetry is shown to give rise to…

Strongly Correlated Electrons · Physics 2025-08-21 Yabo Li , Aditi Mitra

Due to the boundary coupling in a finite system, the zero modes of a standard Su-Schrieffer-Heeger (SSH) model may deviate from exact-zero energy. A recent experiment has shown that by increasing the system size or altering gain or loss…

Quantum Physics · Physics 2020-02-10 Zhihao Xu , Rong Zhang , Shu Chen , Libin Fu , Yunbo Zhang

The union of topology and non-Hermiticity has led to the unveiling of many intriguing phenomena. We introduce a synthetic spin-engineered model belonging to symmetry class AI, which is a rare occurrence, and demonstrate the emergence of a…

Mesoscale and Nanoscale Physics · Physics 2024-05-08 Ronika Sarkar , Ayan Banerjee , Awadhesh Narayan

We study the topological optical states in one-dimensional (1D) dimerized ultracold atomic chains, as an extension of the Su-Schrieffer-Heeger (SSH) model. By taking the fully retarded near-field and far-field dipole-dipole interactions…

Optics · Physics 2018-08-15 B. X. Wang , C. Y. Zhao

Symmetry protected topological (SPT) states have boundary 't Hooft anomalies that obstruct an effective boundary theory realized in its own dimension with UV completion and an on-site $G$-symmetry. In this work, yet we show that a certain…

Strongly Correlated Electrons · Physics 2019-02-15 Juven Wang , Xiao-Gang Wen , Edward Witten

The phenomenon of PT (parity- and time-reversal) symmetry breaking is conventionally associated with a change in the complex mode spectrum of a non-Hermitian system that marks a transition from a purely oscillatory to an exponentially…

This article studies a non-Hermitian Su-Schrieffer-Heeger (SSH) model which has periodically staggered Hermitian and non-Hermitian dimers. The changes in topological phases of the considered chiral symmetric model with respect to the…

Quantum Physics · Physics 2024-12-30 A Niveth , S Karthiga , M Senthilvelan

We study the Su-Schrieffer-Hegger model, perhaps the simplest realization of a topological insulator, in the presence of an embedded impurity superlattice. We consider the impact of the said impurity by changing the hopping amplitudes…

Materials Science · Physics 2024-02-09 Julio César Pérez-Pedraza , José Eduardo Barrios-Vargas , Alfredo Raya

Parity-time (PT) symmetry and anti-PT symmetry have attracted extensive interest for their non-Hermitian spectral properties, particularly the emergence of purely real and imaginary eigenvalues in their symmetry-unbroken regime,…

Topological edge states arise in parity-time ($\mathcal{PT}$)-symmetric non-unitary quantum dynamics but have so far only been discussed in the $\mathcal{PT}$-symmetry-unbroken regime. Here we report the experimental detection of robust…

Quantum Physics · Physics 2019-06-19 Lei Xiao , Xingze Qiu , Kunkun Wang , Barry C. Sanders , Wei Yi , Peng Xue

We demonstrate that genuinely non-Hermitian topological phases and corresponding topological phase transitions can be naturally realized in monitored quantum circuits, exemplified by the paradigmatic non-Hermitian Su-Schrieffer-Heeger…

Mesoscale and Nanoscale Physics · Physics 2022-08-26 Christoph Fleckenstein , Alberto Zorzato , Daniel Varjas , Emil J. Bergholtz , Jens H. Bardarson , Apoorv Tiwari

A prominent feature of some one-dimensional non-Hermitian systems is that all right-eigenstates of the non-Hermitian Hamiltonian are localized in one end of the chain. The topological and trivial phases are distinguished by the emergence of…

Mesoscale and Nanoscale Physics · Physics 2019-07-17 Motohiko Ezawa

We study a one-dimensional topological superconductor, the Kitaev chain, under the influence of a non-Hermitian but $\mathcal{PT}$-symmetric potential. This potential introduces gain and loss in the system in equal parts. We show that the…

Mesoscale and Nanoscale Physics · Physics 2017-05-17 Henri Menke , Moritz M. Hirschmann

The current understanding of the role of topology in non-Hermitian (NH) systems and its far-reaching physical consequences observable in a range of dissipative settings are reviewed. In particular, how the paramount and genuinely NH concept…

Mesoscale and Nanoscale Physics · Physics 2021-03-03 Emil J. Bergholtz , Jan Carl Budich , Flore K. Kunst

In 1998, Carl Bender challenged the perceived wisdom of quantum mechanics that the Hamiltonian operator describing any quantum mechanical system has to be Hermitian. He showed that Hamiltonians that are invariant under combined parity-time…

Topological phenomena in non-Hermitian systems have recently become a subject of great interest in the photonics and condensed-matter communities. In particular, the possibility of observing topologically-protected edge states in…

Mesoscale and Nanoscale Physics · Physics 2020-04-02 Pablo Reséndiz-Vázquez , Konrad Tschernig , Armando Perez-Leija , Kurt Busch , Roberto de J. León-Montiel

Topological semimetals exhibit protected band crossings in momentum space, accompanied by corresponding surface states. Non-Hermitian Hamiltonians introduce geometry-sensitive features that dissolve this bulk-boundary correspondence…

Mesoscale and Nanoscale Physics · Physics 2025-06-18 Megan Schoenzeit , Chang Shu , Kai Zhang , Kai Sun

Non-Hermitian topological insulators have attracted considerable attention due to their distinctive energy band characteristics and promising applications. Here, we systematically investigate non-Hermitian M\"obius insulators and…

Mesoscale and Nanoscale Physics · Physics 2025-06-18 Wenjie Zhang , Yuting Yang , Xiaopeng Shen , Liwei Shi , Zhi Hong Hang