TOD

Abstract

In superfluid helium and in atomic Bose-Einstein condensates, quantum mechanics constrains the rotational motion to discrete filaments of fixed circulation which is equal to Planck's constant divided by the mass of the relevant boson. Because of their simplicity (no viscosity, vorticity confined to vortex lines, fixed circulation), quantum fluids are ideal systems where to study the topology of vortex flows. In this talk I shall report results on the motion of vortex rings perturbed by Kelvin waves (a classical problem first studied by Lord Kelvin), vortex bundles, vortex knots and turbulent tangles of such discrete vortices. In the case of turbulence, I shall focus on its properties, and the relation between kinetic energy and vortex length.