2012/11/27 by Jing-Xin Cui, Jingxin Cui, Xia-Ji Liu +2
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #Quantum, superfluid, helium dynamics #cond-mat.quant-gas #quant-ph
paper · pdf · doi:10.1103/physreva.86.053628
published as Phys. Rev. A 86 053628 (2012) · 6 pages, 6 figures
openalex publication_date 2012/11/27 · arxiv created 2013/01/22 · arxiv updated 2013/01/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We theoretically investigate a Rashba spin-orbit-coupled Fermi gas near Feshbach resonances, by using mean-field theory and a two-channel model that takes into account explicitly Feshbach molecules in the closed channel. In the absence of spin-orbit coupling, when the channel coupling g between the closed and the open channels is strong, it is widely accepted that the two-channel model is equivalent to a single-channel model that excludes Feshbach molecules. This is the so-called broad resonance limit, which is well satisfied by ultracold atomic Fermi gases of 6Li atoms and 40K atoms in current experiments. Here, with Rashba spin-orbit coupling we find that the condition for equivalence becomes much more stringent. As a result, the single-channel model may already be insufficient to describe properly an atomic Fermi gas of 40K atoms at a moderate spin-orbit coupling. We determine a characteristic channel coupling strength gc as a function of the spin-orbit-coupling strength, above which the single-channel and two-channel models are approximately equivalent. We also find that for narrow resonance with small-channel coupling, the pairing gap and molecular fraction are strongly suppressed by SO coupling. Our results can be readily tested in 40K atoms by using optical molecular spectroscopy.