Interaction induced topological protection in one-dimensional conductors

TL;DR

This paper explores how interactions in one-dimensional conductors can induce topological phases, leading to metallic states with gapped single-particle excitations and potential topological edge states.

Contribution

It demonstrates that two different 1D models share a low-energy effective theory where interactions induce topological or trivial phases with gapped excitations.

Findings

Interactions can induce topological phases with gapless edge states.

Both models exhibit metallic phases with all single-particle excitations gapped.

Topological states show insensitivity to disorder.

Abstract

We discuss two one-dimensional model systems -- the first is a single channel quantum wire with Ising anisotropy, while the second is two coupled helical edge states. We show that the two models are governed by the same low energy effective field theory, and interactions drive both systems to exhibit phases which are metallic, but with all single particle excitations gapped. We show that such states may be either topological or trivial; in the former case, the system demonstrates gapless end states, and insensitivity to disorder.