title: Localized Majorana-Like Modes in a Number-Conserving Setting: An Exactly Solvable Model.
abstract: In this Letter we present, in a number conserving framework, a model of interacting fermions in a two-wire geometry supporting nonlocal zero-energy Majorana-like edge excitations. The model has an exactly solvable line, on varying the density of fermions, described by a topologically nontrivial ground state wave function. Away from the exactly solvable line we study the system by means of the numerical density matrix renormalization group. We characterize its topological properties through the explicit calculation of a degenerate entanglement spectrum and of the braiding operators which are exponentially localized at the edges. Furthermore, we establish the presence of a gap in its single particle spectrum while the Hamiltonian is gapless, and compute the correlations between the edge modes as well as the superfluid correlations. The topological phase covers a sizable portion of the phase diagram, the solvable line being one of its boundaries.
authors.affiliation: Departamento de Física-ICEx-Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.|NEST, Scuola Normale Superiore & Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
authors.forename: Fernando
authors.initials: F
authors.lastname: Iemini
authors.affiliation: NEST, Scuola Normale Superiore & Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mazza
authors.affiliation: NEST, Scuola Normale Superiore & Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Rossini
authors.affiliation: NEST, Scuola Normale Superiore & Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.|ICTP, Strada Costiera 11, 34151 Trieste, Italy.
authors.forename: Rosario
authors.initials: R
authors.lastname: Fazio
authors.affiliation: Institute of Theoretical Physics, TU Dresden, D-01062 Dresden, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Diehl