Stability of Topological Insulators with Non-Abelian Edge Excitations

TL;DR

This paper investigates the stability of non-Abelian topological insulators by analyzing time-reversal invariant interactions that can gap their edge states, extending previous work on their Z_2 topological classification.

Contribution

It provides explicit forms of interactions that stabilize non-Abelian edge states by projecting from Abelian parent states, advancing understanding of their robustness.

Findings

Identifies interactions that gap non-Abelian edge excitations.

Shows stability linked to Z_2 anomaly and index.

Extends stability analysis to non-Abelian topological insulators.

Abstract

Chiral-antichiral pairs of non-Abelian Hall states, like the Pfaffian, Read-Rezayi and NASS states, can be used to model two-dimensional time-reversal invariant topological insulators. Their stability was shown to be associated to the presence of a Z_2 anomaly and characterized by the same Z_2 index introduced for free fermion and Abelian systems. In this work, we continue the stability analysis by providing the form of time-reversal invariant interactions that gap the non-Abelian edge excitations. Our approach is based on the description of non-Abelian states as projections of corresponding "parent" Abelian states.