Pseudo-Hermitian Topology of Multiband Non-Hermitian Systems

• URL: http://arxiv.org/abs/2405.17749v1
• Date: Tue, 28 May 2024 02:04:09 GMT
• Title: Pseudo-Hermitian Topology of Multiband Non-Hermitian Systems
• Authors: Jung-Wan Ryu, Jae-Ho Han, Chang-Hwan Yi, Hee Chul Park, Moon Jip Park,
• Abstract summary: Non-Hermitian multibands can be topologically non-trivial without exceptional points in two-dimensional space. Our work builds on the fundamental and comprehensive understanding of non-Hermitian multiband systems.
• Score: 1.188383832081829
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The complex eigenenergies and non-orthogonal eigenstates of non-Hermitian systems exhibit unique topological phenomena that cannot appear in Hermitian systems. Representative examples are the non-Hermitian skin effect and exceptional points. In a two-dimensional parameter space, topological classifications of non-separable bands in multiband non-Hermitian systems can be established by invoking a permutation group, where the product of the permutation represents state exchange due to exceptional points in the space. We unveil in this work the role of pseudo-Hermitian lines in non-Hermitian topology for multiple bands. Contrary to current understanding, the non-separability of non-Hermitian multibands can be topologically non-trivial without exceptional points in two-dimensional space. Our work builds on the fundamental and comprehensive understanding of non-Hermitian multiband systems and also offers versatile applications and realizations of non-Hermitian systems without the need to consider exceptional points.

Related papers

• Topological Order in the Spectral Riemann Surfaces of Non-Hermitian Systems [44.99833362998488]
  We show topologically ordered states in the complex-valued spectra of non-Hermitian systems. These arise when the distinctive exceptional points in the energy surfaces of such models are annihilated. We illustrate the characteristics of the topologically protected states in a non-Hermitian two-band model.
  arXiv  Detail & Related papers  (2024-10-24T10:16:47Z)
• Exceptional points in SSH-like models with hopping amplitude gradient [41.94295877935867]
  Recent interest in exceptional points has led to re-examination of non-Hermitian generalizations of many physical models. In such non-Hermitian systems, singular points called exceptional points (EPs) appear that are of interest for applications in super-resolution sensing systems and topological lasers. It is found that while the existence of the EPs is due to the nonreciprocal couplings, the number, position, and order of the EPs can all be altered by the addition of the hopping amplitude gradient.
  arXiv  Detail & Related papers  (2024-08-01T19:09:59Z)
• Non-chiral non-Bloch invariants and topological phase diagram in non-unitary quantum dynamics without chiral symmetry [26.179241616332387]
  We identify the non-Bloch topological phase diagram of a one-dimensional (1D) non-Hermitian system without chiral symmetry. We find that such topological invariants can distinguish topologically distinct gapped phases. Our work provides a useful platform to study the interplay among topology, symmetries and the non-Hermiticity.
  arXiv  Detail & Related papers  (2024-07-26T03:29:30Z)
• Homotopy, Symmetry, and Non-Hermitian Band Topology [4.777212360753631]
  We show that non-Hermitian bands exhibit intriguing exceptional points, spectral braids and crossings. We reveal different Abelian and non-Abelian phases in $mathcalPT$-symmetric systems. These results open the door for theoretical and experimental exploration of a rich variety of novel topological phenomena.
  arXiv  Detail & Related papers  (2023-09-25T18:00:01Z)
• Exceptional Classifications of Non-Hermitian Systems [2.218316486552747]
  Eigenstate coalescence in non-Hermitian systems is widely observed in diverse scientific domains. We propose an exhaustive classification framework for exceptional points (EPs) in non-Hermitian physical systems.
  arXiv  Detail & Related papers  (2023-06-12T08:53:33Z)
• From Hermitian critical to non-Hermitian point-gapped phases [0.0]
  We show the equivalence of topological invariants in critical systems with non-hermitian point-gap phases. This correspondence may carry over to other features beyond topological invariants.
  arXiv  Detail & Related papers  (2022-11-24T17:16:20Z)
• Non-Hermitian Topology and Exceptional-Point Geometries [15.538614667230366]
  Non-Hermitian theory is a theoretical framework that excels at describing open systems. Non-Hermitian framework consists of mathematical structures that are fundamentally different from those of Hermitian theories.
  arXiv  Detail & Related papers  (2022-04-19T12:41:31Z)
• Non-Hermitian $C_{NH} = 2$ Chern insulator protected by generalized rotational symmetry [85.36456486475119]
  A non-Hermitian system is protected by the generalized rotational symmetry $H+=UHU+$ of the system. Our finding paves the way towards novel non-Hermitian topological systems characterized by large values of topological invariants.
  arXiv  Detail & Related papers  (2021-11-24T15:50:22Z)
• Bridging the gap between topological non-Hermitian physics and open quantum systems [62.997667081978825]
  We show how to detect a transition between different topological phases by measuring the response to local perturbations. Our formalism is exemplified in a 1D Hatano-Nelson model, highlighting the difference between the bosonic and fermionic cases.
  arXiv  Detail & Related papers  (2021-09-22T18:00:17Z)
• Pseudo-Hermitian Levin-Wen models from non-semisimple TQFTs [24.70079638524539]
  We construct large classes of exactly solvable pseudo-Hermitian 2D spin Hamiltonians. We identify the ground state system on a surface with the value assigned to the surface by a non-semisimple TQFT generalizing the Turaev-Viro model.
  arXiv  Detail & Related papers  (2021-08-24T15:39:41Z)
• Topological characterization of non-Hermitian multiband systems using Majorana's Stellar Representation [1.5484595752241122]
  Majorana's stellar representation (MSR) is applied to 1D multiband models consisting of asymmetric nearest-neighbor hopping and imaginary on-site potentials. The number of edge states isolated from the continuous bulk bands in the complex energy plane is successfully linked with a topological invariant constructed from MSR. Cases with the so-called non-Hermitian skin effect are also studied, showing that the bulk-boundary correspondence between our defined winding numbers and isolated edge states can be restored.
  arXiv  Detail & Related papers  (2020-02-18T11:15:47Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.