Condensed Matter Seminar

Erkki Thuneberg
Yale University
(visiting from University of Oulu, Finland)

Thursday, November 1, 2007
1:00 pm in SPL 52

Pi-states and dissipative currents in superfluid 3He Jospehson junctions

Abstract: Analogously to point contacts between superconductors, a small aperture connecting two superfluid reservoirs shows Josephson effects. The analogy is particularly strong in the fermion superfluid 3He, where Andreev bound states are formed at the junction. New effects arise because of the multi-component order parameter of superfluid 3He: the Andreev states are spin split and the soft degrees of freedom in the reservoirs respond to the state of the junction. We show how these lead to pi-states in the equilibrium current-phase relationship and to spin-wave radiation under a constant bias. The theoretical results are compared with experiments.