Solitary waves on vortex lines in Ginzburg--Landau models

Axisymmetric disturbances that preserve their form as they move along the vortex lines in uniform Bose-Einstein condensates are obtained numerically by the solution of the Gross-Pitaevskii equation. A continuous family of such solitary waves is shown in the momentum ($p$) -- substitution energy ($\hat{\cal E}$) plane with $p\to 0.09 \rho \kappa^3/c^2, \hat{\cal E}\to 0.091 \rho \kappa^3/c$ as $U \to c$, where $\rho$ is the density, $c$ is the speed of sound, $\kappa$ is the quantum of circulation and $U$ is the solitary wave velocity. It is shown that collapse of a bubble captured by a vortex line leads to the generation of such solitary waves in condensates. The various stages of collapse are elucidated. In particularly, it is shown that during collapse the vortex core becomes significantly compressed and after collapse two solitary wave trains moving in opposite directions are formed on the vortex line.