Solitons, solitonic vortices, and vortex rings in a
confined Bose-Einstein condensate
S. Komineasa and N. Papanicolaoub aTheory of Condensed Matter Group, Cavendish Laboratory,
Madingley Road, Cambridge CB3 0HE, United Kingdom bDepartment of Physics, University of Crete
and Research Center of Crete, Heraklion, Greece
Abstract
Quasi-one-dimensional solitons that may occur in an elongated
Bose-Einstein condensate become unstable at high particle density.
We study two basic modes of instability and the corresponding
bifurcations to genuinely three-dimensional solitary waves
such as axisymmetric vortex rings and non-axisymmetric solitonic
vortices.
We calculate the profiles of the above structures and examine their
dependence on the velocity of propagation along a cylindrical trap.
At sufficiently high velocity, both the vortex ring and the solitonic vortex
transform into an axisymmetric soliton. We also calculate the energy-momentum
dispersions and show that a Lieb-type mode appears in the excitation
spectrum for all particle densities.