Transverse Josephson vortices and localized states in stacked Bose–Einstein condensates

The stacks of Bose–Einstein condensates coupled by long Josephson junctions present a rich phenomenology feasible to experimental realization and specially suitable for technological applications as the nonlinear-optics and superconducting analogs have already proved. Among this, we show that transverse Bloch waves excited in arrays of one-dimensional coupled condensates can carry tunneling superflows whose dynamical stability depends on the quasimomentum. Across the stacks with periodic boundary conditions, forming closed ring-shaped systems, such Bloch states yield transverse Josephson vortices with a generic non-integer circulation in units of h/m. Additionally, the superpositions of degenerate linear Bloch waves can suppress the supercurrents and give rise to families of nonlinear standing-wave states with strong (transverse) spatial localization. Stable states of this type can also be found in finite size systems. (paper)