We construct a family of two-dimensional non-Abelian topological phases from coupled wires using a non-Abelian bosonization approach. We then demonstrate how to determine the nature of the non-Abelian topological order (in particular, the anyonic excitations and the topological degeneracy on the torus) realized in the resulting gapped phases of matter. This paper focuses on the detailed case study of a coupled-wire realization of the bosonic su(2) 2 Moore-Read state, but the approach we outline here can be extended to general bosonic su(2) k topological phases described by non-Abelian Chern-Simons theories. We also discuss possible generalizations of this approach to the construction of three-dimensional non-Abelian topological phases. IADECOLA, NEUPERT, CHAMON, AND MUDRY PHYSICAL REVIEW B 99, 245138 (2019) 245138-2 GROUND-STATE DEGENERACY OF NON-ABELIAN … PHYSICAL REVIEW B 99, 245138 (2019)(2.6e)With these definitions, it follows that the Hamiltonian density associated with the free Lagrangian density (2.1) is given by(2.7)Rewriting the free theory (2.1) in terms of the currents (2.4) amounts to performing a non-Abelian bosonization of the free theory. This rewriting highlights the fact that a theory of multiple flavors of free fermions can be broken up into independent charge [u(1)], spin [su(2) N c ], and color (orbital) [su(N c ) 2 ] sectors.
B. Intrawire interactionsHaving rewritten the free theory (2.1) in terms of the non-Abelian currents (2.4), we now wish to isolate the su(2) N c spin degrees of freedom by removing the u(1) charge and su(N c ) 2 color (orbital) degrees of freedom from the low-energy sector of the theory. We accomplish this by adding interactions that gap out the latter pair of degrees of freedom. 245138-3 IADECOLA, NEUPERT, CHAMON, AND MUDRY PHYSICAL REVIEW B 99, 245138 (2019) The interaction (3.2) can be better understood by rewriting the su(2) k currents in terms of auxiliary degrees of freedom. This rewriting must preserve the su (2) k current algebra, which is encoded in the operator product expansion (OPE) [66] J a L,y (v) J˜a L,ỹ (w) ∼ δ y,ỹ (k/2) δ aã v 2 − w 2 + i aãb J b L,y (w) v − w , (3.3) 245138-4 GROUND-STATE DEGENERACY OF NON-ABELIAN … PHYSICAL REVIEW B 99, 245138 (2019)