Quantized Superfluid Vortex Rings in the Unitary Fermi Gas
Aurel Bulgac, Michael McNeil Forbes, Michelle M. Kelley +2 more
In a recent article, Yefsah et al. [Nature (London) 499, 426 (2013)] report the observation of an unusual excitation in an elongated harmonically trapped unitary Fermi gas. After phase imprinting a domain wall, they observe oscillations almost an order of magnitude slower than predicted by any theory of domain walls which they interpret as a "heavy soliton" of inertial mass some 200 times larger than the free fermion mass or 50 times larger than expected for a domain wall. We present compelling evidence that this "soliton" is instead a quantized vortex ring, by showing that the main aspects of the experiment can be naturally explained within the framework of time-dependent superfluid density functional theories.
arXiv:1306.4266•Physical Review Letters•Jan 16, 2014•84 citations