We numerically model turbulence in a trapped atomic Bose–Einstein condensate by solving the Gross–Pitaevskii nonlinear Schroedinger equation. We find that, after an initial growth, the vortex length decays approximately as t−1 where t is time, consistent with experiments in turbulent superfluid helium, and that the velocity components obey power-law statistics, again in agreement with observati...

We capture the decay of a quantized vortex ring in superfluid helium-4 by imaging particles trapped on the vortex core. The ring shrinks in time, providing direct evidence for the dissipation of energy in the superfluid. The ring with trapped particles collapses more slowly than predicted by an available theory, but the collapse rate can be predicted correctly if the trapping of the particles o...

It is shown that a vortex trapped in one of the banks of a planar edge-type Josephson junction in a narrow thin-film superconducting strip can change drastically the dependence of the junction critical current on the applied field, IcðHÞ. When the vortex is placed at certain discrete positions in the strip middle, the pattern IcðHÞ has zero at H 1⁄4 0 instead of the traditional maximum of ‘0-ty...

In a shaken Bose-Einstein condensate, confined in a vibrating trap, there can appear different nonlinear coherent modes. Here we concentrate on two types of such coherent modes, vortex ring solitons and vortex rings. In a cylindrical trap, vortex ring solitons can be characterized as nonlinear Hermite-Laguerre modes, whose description can be done by means of optimized perturbation theory. The e...

We consider the vortex state solution for a rotating cloud of trapped, Bose Einstein condensed alkali atoms and study finite temperature effects. We find that thermally excited vortex waves can distort the vortex state significantly, even at the very low temperatures relevant to the experiments. PACS numbers 0.35 Fi, 5.30 Jp, 32.80 Pj

We consider the vortex structure of a rapidly rotating trapped atomic Bose-Einstein condensate in the presence of a corotating periodic optical lattice potential. We observe a rich variety of structural phases which reflect the interplay of the vortex-vortex and vortex-lattice interactions. The lattice structure is very sensitive to the ratio of vortices to pinning sites and we observe structur...

We perform Monte Carlo studies of vortices in three dimensions in a cylindrical confinement, with uniform and nonuniform density. The former is relevant to rotating 4He; the latter is relevant to a rotating trapped Bose-Einstein condensate. In the former case, we find dominant angular thermal vortex fluctuations close to the cylinder wall. For the latter case, a novel effect is that at low temp...

We study two-component spatial optical solitons carrying an angular momentum and propagating in a self-focusing saturable nonlinear medium. When one of the components is small, such vector solitons can be viewed as a self-trapped vortex beam that guides either the fundamental or first-order guided mode, and they are classified as single- and double-vortex vector solitons. For such composite vor...

The surface quasi-geostrophic (SQG) model describes the evolution of buoyancy at vertical boundaries in the limit of infinitesimal Rossby number. In this regime, the quasigeostrophic approximations are expected to hold. Numerical simulation of the SQG model often generate small-scale vortices which may have Rossby numbers that approach unity and may be outside the range of SQG. In this thesis w...