2008/09/08 by Andreas Dewes, Tobias Gaber, T. Gaber +6
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.101.247001
published as Phys. Rev. Lett. 101, 247001 (2008)
arxiv created 2008/09/08 · openalex publication_date 2008/12/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Josephson junctions with a phase drop of \ensuremathπ in the ground state allow us to create vortices of supercurrent carrying only half of the magnetic flux quantum \ensuremathΦ0\ensuremath≈2.07\ifmmode×\else\texttimes\fi10^\ensuremath-15 Wb. Such semifluxons have twofold degenerate ground states denoted \ensuremath\uparrow (with flux +\ensuremathΦ0/2 and supercurrent circulating clockwise) and \ensuremath\downarrow (with flux \ensuremath-\ensuremathΦ0/2 and supercurrent circulating counterclockwise). We investigate a molecule consisting of two coupled semifluxons in a 0-\ensuremathπ-0 long Josephson junction. The fluxes (polarities) of semifluxons are measured by two on-chip SQUIDs. By varying the dc bias current applied to the 0-\ensuremathπ-0 junction, we demonstrate controllable manipulation and switching between two states, \ensuremath\uparrow\ensuremath\downarrow and \ensuremath\downarrow\ensuremath\uparrow, of a semifluxon molecule. These results provide a major step towards employing semifluxons as bits or qubits for classical and quantum digital electronics.