Whenever a gas of bosons is rapidly cooled below the BEC transition
temperature, different domains of the order parameter appear and the
initially turbulent system evolves into a condensate with a few
long-living excited states, such as vortices.
If the system is confined in an axially symmetric, elongated potential,
then vortices tend to align along the short transverse directions and
acquire solitonic properties.
I will present the recent experimental results obtained in our lab in
Trento, where we have been able to directly observe and characterize the
static and dynamical properties of such solitonic vortices.
Boundary effects in a symmetric prolate geometry make vortices move
axially and rotate around the axis, providing two degrees of freedom that
are crucial for studying vortex-vortex interaction mechanisms, which are
usually not accessible in other ultracold gas systems with vortices, such
as 2D systems across the BKT transition temperature or 3D superfluids
I will show how the combination of our experimental findings and the
theoretical simulations provide a clear picture on the physics of the
interaction mechanisms between quantised vortices that might represent the
fundamental processes at the basis of quantum turbulence.