title: Phase imprinting in equilibrating Fermi gases: the transience of vortex rings and other defects.
abstract: We present numerical simulations of phase imprinting experiments in ultracold trapped Fermi gases, which were obtained independently and are in good agreement with recent experimental results. Our focus is on the sequence and evolution of defects using the fermionic time-dependent Ginzburg-Landau equation, which contains dissipation necessary for equilibration. In contrast to other simulations, we introduce small, experimentally unavoidable symmetry breaking, particularly that associated with thermal fluctuations and with the phase-imprinting tilt angle, and we illustrate their dramatic effects. As appears consistent with experiment, the former causes vortex rings in confined geometries to move to the trap surface and rapidly decay into more stable vortex lines. The latter aligns the precessing and relatively long-lived vortex filaments, rendering them difficult to distinguish from solitons.
authors.affiliation: James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Scherpelz
authors.affiliation: James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Karmela
authors.initials: K
authors.lastname: Padavić
authors.affiliation: James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Rançon
authors.affiliation: Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA and Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Glatz
authors.affiliation: Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Igor S
authors.initials: IS
authors.lastname: Aranson
authors.affiliation: James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: K
authors.initials: K
authors.lastname: Levin