Related papers: Exceptional Second-Order Topological Insulators

Exceptional Second-Order Topological Insulators

URL: http://arxiv.org/abs/2411.06898v1
Date: Mon, 11 Nov 2024 11:55:48 GMT
Title: Exceptional Second-Order Topological Insulators
Authors: Yutaro Tanaka, Daichi Nakamura, Ryo Okugawa, Kohei Kawabata,
Abstract summary: Point-gap topological phases of non-Hermitian systems exhibit exotic boundary states that have no counterparts in Hermitian systems. We propose exceptional second-order topological insulators, exhibiting second-order boundary states stabilized by point-gap topology. Our work enlarges the family of point-gap topological phases in non-Hermitian systems.
Score: 0.0
License:
Abstract: 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 with reflection symmetry. Based on this classification, we propose exceptional second-order topological insulators, exhibiting second-order boundary states stabilized by point-gap topology. As an illustrative example, we uncover a two-dimensional exceptional second-order topological insulator with point-gapless corner states. Furthermore, we identify a three-dimensional exceptional second-order topological insulator that features hinge states with isolated exceptional points, representing second-order topological phases intrinsic to non-Hermitian systems. Our work enlarges the family of point-gap topological phases in non-Hermitian systems.

Related papers

Gapless Floquet topology [40.2428948628001]
We study the existence of topological edge zero- and pi-modes despite the lack of bulk gaps in the quasienergy spectrum. We numerically study the effect of interactions, which give a finite lifetime to the edge modes in the thermodynamic limit with the decay rate consistent with Fermi's Golden Rule.
arXiv Detail & Related papers (2024-11-04T19:05:28Z)
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)
Breakdown of boundary criticality and exotic topological semimetals in $\mathcal{P}\mathcal{T}$-invariant systems [2.253370796182325]
We show that periodic driving can break the boundary criticality of a PT-invariant system. We discover exotic second-order Dirac and nodal-line semimetals with coexisting surface and hinge Fermi arcs.
arXiv Detail & Related papers (2024-09-09T08:38:27Z)
Universal platform of point-gap topological phases from topological materials [0.0]
We propose a simple and universal platform of point-gap topological phases constructed from Hermitian topological insulators and superconductors. We show that (d-1)-dimensional point-gap topological phases are realized by making a boundary in d-dimensional topological insulators and superconductors dissipative.
arXiv Detail & Related papers (2023-04-17T09:38:17Z)
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)
Topological Anderson insulators with different bulk states in quasiperiodic chains [1.6530012863603747]
We investigate the topology and localization of one-dimensional Hermitian and non-Hermitian Su-Schrieffer-Heeger chains with quasiperiodic hopping modulations. We show the presence of topological extended, intermediate, and localized phases due to the coexistence of independent topological and localization phase transitions.
arXiv Detail & Related papers (2022-01-04T05:32:43Z)
Topological transitions with continuously monitored free fermions [68.8204255655161]
We show the presence of a topological phase transition that is of a different universality class than that observed in stroboscopic projective circuits. We find that this entanglement transition is well identified by a combination of the bipartite entanglement entropy and the topological entanglement entropy.
arXiv Detail & Related papers (2021-12-17T22:01:54Z)
Towards a complete classification of non-chiral topological phases in 2D fermion systems [29.799668287091883]
We argue that all non-chiral fermionic topological phases in 2+1D are characterized by a set of tensors $(Nij_k,Fij_k,Fijm,alphabeta_kln,chidelta,n_i,d_i)$. Several examples with q-type anyon excitations are discussed, including the Fermionic topological phase from Tambara-gami category for $mathbbZ_2N$.
arXiv Detail & Related papers (2021-12-12T03:00:54Z)
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)
Dynamical solitons and boson fractionalization in cold-atom topological insulators [110.83289076967895]
We study the $mathbbZ$ Bose-Hubbard model at incommensurate densities. We show how defects in the $mathbbZ$ field can appear in the ground state, connecting different sectors. Using a pumping argument, we show that it survives also for finite interactions.
arXiv Detail & Related papers (2020-03-24T17:31:34Z)

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