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Register a new userNon-topological parafermions in a one-dimensional fermionic model with even multiplet pairing
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We discuss a one-dimensional fermionic model with a generalized $mathbb{Z}_{N}$ even multiplet pairing extending Kitaev $mathbb{Z}_{2}$ chain. The system shares many features with models believed to host localized edge parafermions, the most prominent being a similar bosonized Hamiltonian and a $mathbb{Z}_{N}$ symmetry enforcing an $N$-fold degenerate ground state robust to certain disorder. Interestingly, we show that the system supports a pair of parafermions but they are non-local instead of being boundary operators. As a result, the degeneracy of the ground state is only partly topological and coexists with spontaneous symmetry breaking by a (two-particle) pairing field. Each symmetry-breaking sector is shown to possess a pair of Majorana edge modes encoding the topological twofold degeneracy. Surrounded by two band insulators, the model exhibits for $N=4$ the dual of an $8 pi$ fractional Josephson effect highlighting the presence of parafermions.
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