Abstract
- A variety of turbulent regimes have been observed in quantum fluids, some being analagous to classical fluids and others being uniquely quantum in behaviour. The development of optical box-traps for atomic condensates means that this turbulence is more straightforward to analyse than in harmonic trapping-potentials. In several recent publications, weak-wave turbulence (WWT) has been observed in otherwise uniform systems with hard-wall confinement. In each case with slightly different scaling-laws and different arguments as to the underlying turbulence mechanism. This thesis explores steady turbulence in optical box-traps numerically. We perform simulations of turbulence from the ground state through to a quasi-steady state, over a wide range of forcing amplitudes. In doing so we observe both ordinary WWT with k−3 scaling, and the steeper k−3.5 scaling which has been observed in recent experiments. Using a recent reformulation of energy spectral densities, we show that this k−3.5 scaling is a unique regime to ordinary WWT. The steeper scaling is potentially driven by less weakly nonlinear wave interactions, and does not seem to be directly due to vortices as previously suggested. We also demonstrate that accounting for quantum phase is essential when calculating energy spectral densities.