Generating and Classifying Turbulence in Bose-Einstein condensates
Seminar Room 1, Newton Institute
Vortices are a hallmark signature of a turbulent flow. Quantum vortices differ from their classical counterparts because of the quantization of circulation in superfluid flow. This means that the rotational motion of a superfluid is constrained to discrete vortices which all have the same core structure. Turbulence in superfluid Helium has been the subject of many recent experimental and theoretical investigations recently reviewed by Skrbek and Sreenivasan . Recently, experimentalists have been able to visualise individual vortex lines and reconnection events using tracer particles. Weakly interacting Bose-Einstein condensates present a unique opportunity to resolve the structure of vortices and in turn study the dynamics of a vortex tangle (as has recently been created in an atomic cloud).
We investigate ways of generating turbulence in atomic systems by numerically stirring the condensate using a Gaussian 'spoon' (analogous to a laser beam in the experiments), and study the isotrophy of the resulting vortex tangle depending on when the path the spoon stirs is circular or random. We model the system using the Gross-Pitaevskii Equation.
 L. Skrbek and K.R. Sreenivasan, PoF 24, 011301 (2012)  G.P. Bewley et al. PNAS 105, 13707 (2008).  E.A.L. Henn et al. PRL 103, 04301 (2009).