2018/01/31 by Leonardo Mazza, Fernando Iemini, Marcello Dalmonte +1 · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.98.201109
published as Phys. Rev. B 98, 201109 (2018) · 12 pages, 3 figures
arxiv created 2018/11/16 · arxiv updated 2018/11/21
We discuss a one-dimensional fermionic model with a generalized ℤN even multiplet pairing extending Kitaev ℤ2 chain. The system shares many features with models believed to host localized edge parafermions, the most prominent being a similar bosonized Hamiltonian and a ℤN 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 π fractional Josephson effect highlighting the presence of parafermions.