Dynamical topological excitations in parafermion chains

TL;DR

This paper demonstrates the existence and robustness of zero and finite energy topological excitations in many-body parafermion chains using tensor network and kernel polynomial methods, advancing understanding of fractional topological matter.

Contribution

It introduces a novel combination of tensor network and kernel polynomial techniques to study dynamical excitations in parafermion chains, revealing zero modes and their stability.

Findings

Zero energy modes appear at the edges of topological parafermion chains.

Topological modes are robust against various perturbations.

Weak coupling of chains leads to in-gap excitations.

Abstract

Topological excitations in many-body systems are one of the paradigmatic cornerstones of modern condensed matter physics. In particular, parafermions are elusive fractional excitations potentially emerging in fractional quantum Hall-superconductor junctions, and represent one of the major milestones in fractional quantum matter. Here, by using a combination of tensor network and kernel polynomial techniques, we demonstrate the emergence of zero modes and finite energy excitations in many-body parafermion chains. We show the appearance of zero energy modes in the many-body spectral function at the edge of a topological parafermion chain, their relation with the topological degeneracy of the system, and we compare their physics with the Majorana bound states of topological superconductors. We demonstrate the robustness of parafermion topological modes with respect to a variety of perturbations, and we show how weakly coupled parafermion chains give rise to in-gap excitations. Our results exemplify the versatility of tensor network methods for studying dynamical excitations of interacting parafermion chains, and highlight the robustness of topological modes in parafermion models.