title: Unpaired Majorana Modes in Josephson-Junction Arrays with Gapless Bulk Excitations.
abstract: The search for Majorana bound states in solid-state physics has been limited to materials that display a gap in their bulk spectrum. We show that such unpaired states appear in certain quasi-one-dimensional Josephson-junction arrays with gapless bulk excitations. The bulk modes mediate a coupling between Majorana bound states via the Ruderman-Kittel-Yosida-Kasuya mechanism. As a consequence, the lowest energy doublet acquires a finite energy difference. For a realistic set of parameters this energy splitting remains much smaller than the energy of the bulk eigenstates even for short chains of length L∼10.
authors.affiliation: Department of Physics and Astronomy, Rutgers The State University of New Jersey, 136 Frelinghuysen road, Piscataway, New Jersey 08854, USA.
authors.forename: M
authors.initials: M
authors.lastname: Pino
authors.affiliation: Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Tsvelik
authors.affiliation: Department of Physics and Astronomy, Rutgers The State University of New Jersey, 136 Frelinghuysen road, Piscataway, New Jersey 08854, USA.|CNRS, UMR 7589, LPTHE, F-75005 Paris, France.
authors.forename: L B
authors.initials: LB
authors.lastname: Ioffe