Non-abelian bosonization of fermion symmetry-protected topological states

Abstract

Applying the results of Ref.[1], we carry out the non-abelian bosonization for a class of free fermion symmetry-protected topological states (SPTs). The resulting boson theories are non-linear sigma models with topological $\hat{I}¸$ term, thus unifying the field theory description of the (free) fermionic and bosonic SPTs. Tuning $\hat{I}¸$ from $0$ to $2\ddot{I}€$ triggers the topological trivial to non-trivial phase transitions. In addition, applying the same idea to the symmetry-protected critical spin liquids, we obtain the NL$\s$ models for spin SPTs living in one spatial dimension higher.