Stability of topological insulators with non-Abelian edge excitations

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. (paper)