Unconventional edge states in a two-leg ladder

Fuente: arXiv
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Main Authors: Downing, C. A., Martín-Moreno, L., Fox, O. I. R.
Format: Preprint
Published: 2024
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author Downing, C. A.
Martín-Moreno, L.
Fox, O. I. R.
author_facet Downing, C. A.
Martín-Moreno, L.
Fox, O. I. R.
contents Some popular mechanisms for restricting the diffusion of waves include introducing disorder (to provoke Anderson localization) and engineering topologically non-trivial phases (to allow for topological edge states to form). However, other methods for inducing somewhat localized states in elementary lattice models have been historically much less studied. Here we show how edge states can emerge within a simple two-leg ladder of coupled harmonic oscillators, where it is important to include interactions beyond those at the nearest neighbour range. Remarkably, depending upon the interplay between the coupling strength along the rungs of the ladder and the next-nearest neighbour coupling strength along one side of the ladder, edge states can indeed appear at particular energies. In a wonderful manifestation of a type of bulk-edge correspondence, these edge state energies correspond to the quantum number for which additional stationary points appear in the continuum bandstructure of the equivalent problem studied with periodic boundary conditions. Our theoretical results are relevant to a swathe of classical or quantum lattice model simulators, such that the proposed edge states may be useful for applications including waveguiding in metamaterials and quantum transport.
format Preprint
id arxiv_https___arxiv_org_abs_2407_05888
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unconventional edge states in a two-leg ladder
Downing, C. A.
Martín-Moreno, L.
Fox, O. I. R.
Mesoscale and Nanoscale Physics
Some popular mechanisms for restricting the diffusion of waves include introducing disorder (to provoke Anderson localization) and engineering topologically non-trivial phases (to allow for topological edge states to form). However, other methods for inducing somewhat localized states in elementary lattice models have been historically much less studied. Here we show how edge states can emerge within a simple two-leg ladder of coupled harmonic oscillators, where it is important to include interactions beyond those at the nearest neighbour range. Remarkably, depending upon the interplay between the coupling strength along the rungs of the ladder and the next-nearest neighbour coupling strength along one side of the ladder, edge states can indeed appear at particular energies. In a wonderful manifestation of a type of bulk-edge correspondence, these edge state energies correspond to the quantum number for which additional stationary points appear in the continuum bandstructure of the equivalent problem studied with periodic boundary conditions. Our theoretical results are relevant to a swathe of classical or quantum lattice model simulators, such that the proposed edge states may be useful for applications including waveguiding in metamaterials and quantum transport.
title Unconventional edge states in a two-leg ladder
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2407.05888