Fluxon Dynamics in Three Stacked Josephson Junctions

Carlos Gorria

University of the Basque Country. Bilbao, Spain

Abstract: In this work it is presented a system of 3 stacked Josephson-junctions described by a set of 3 coupled sine-Gordon equations. It is shown there are qualitative differences with the well established case of 2 junctions. These nonlinear equations are not Lorenz invariant. We have solved numerically the fully nonlinear equations for different distribution of travelling-wave solutions and we prove the fluxon-antifluxon-fluxon initial condition is the only stable configuration which does not radiate significantly. The interaction produces an "overshoot" in the shape of the antifluxon and its height depends on its velocity and the coupling constant. We obtain analytical solution of the piece-wise linearized equations and it agrees well with the numerical solution of fully nonlinear system when the velocity is small.