Life cycle of superfluid vortices and quantum turbulence in the unitary Fermi gas

Abstract

The unitary Fermi gas (UFG) offers an unique opportunity to study quantum turbulence both experimentally and theoretically in a strongly interacting fermionic superfluid. It yields to accurate and controlled experiments, and admits the only dynamical microscopic description via time-dependent density functional theory (DFT) - apart from dilute bosonic gases - of the crossing and reconnection of superfluid vortex lines conjectured by Feynman in 1955 to be at the origin of quantum turbulence in superfluids at zero temperature. We demonstrate how various vortex configurations can be generated by using well established experimental techniques: laser stirring and phase imprinting. New imagining techniques demonstrated by the MIT group [Ku et al. arXiv:1402.7052] should be able to directly visualize these crossings and reconnections in greater detail than performed so far in liquid helium. We demonstrate the critical role played by the geometry of the trap in the formation and dynamics of a vortex in the UFG and how laser stirring and phase imprint can be used to create vortex tangles with clear signatures of the onset of quantum turbulence.