



01449nas a2200169   4500008004100000245007200041210006900113260001500182520093700197100002301134700001701157700001601174700001501190700001801205700001901223856003701242       2021                        eng d00aSpin chains, defects, and quantum wires for the quantum-double edge0 aSpin chains defects and quantum wires for the quantumdouble edge  c11/23/20213 a<p>Non-Abelian defects that bind Majorana or parafermion zero modes are prominent in several topological quantum computation schemes. Underpinning their established understanding is the quantum Ising spin chain, which can be recast as a fermionic model or viewed as a standalone effective theory for the surface-code edge -- both of which harbor non-Abelian defects. We generalize these notions by deriving an effective Ising-like spin chain describing the edge of quantum-double topological order. Relating Majorana and parafermion modes to anyonic strings, we introduce quantum-double generalizations of non-Abelian defects. We develop a way to embed finite-group valued qunits into those valued in continuous groups. Using this embedding, we provide a continuum description of the spin chain and recast its non-interacting part as a quantum wire via addition of a Wess-Zumino-Novikov-Witten term and non-Abelian bosonization.</p>1 aAlbert, Victor, V.1 aAasen, David1 aXu, Wenqing1 aJi, Wenjie1 aAlicea, Jason1 aPreskill, John  uhttps://arxiv.org/abs/2111.12096