title: Vortex molecules in coherently coupled two-component Bose-Einstein condensates.
abstract: A vortex molecule is predicted in rotating two-component Bose-Einstein condensates whose internal hyperfine states are coupled coherently by an external field. A vortex in one component and one in the other are connected by a domain wall of the relative phase, constituting a "vortex molecule," which features a nonaxisymmetric (pseudo)spin texture with a pair of merons. The binding mechanism of the vortex molecule is discussed based on a generalized nonlinear sigma model and a variational ansatz. The anisotropy of vortex molecules is caused by the difference in the scattering lengths, yielding a distorted vortex-molecule lattice in fast rotating condensates.
authors.affiliation: Department of Physics, Osaka City University, Sumiyoshi-Ku, Osaka 558-8585, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kasamatsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsubota
authors.forename: Masahito
authors.initials: M
authors.lastname: Ueda