2015/03/31 by Wei Yi, Xiaoling Cui · 1 citation
Physics and Astronomy · #cond-mat.quant-gas #cond-mat.supr-con
paper · pdf · doi:10.1103/physreva.92.013620
published as Phys. Rev. A 92, 013620 (2015) · 7 pages, 6 figures, updated with the published version
arxiv created 2015/07/16 · arxiv updated 2015/07/17
We study a new type of Fermi polaron induced by an impurity interacting with an ultracold Fermi superfluid. Due to the three-component nature of the system, the polaron can become trimer-like with a non-universal energy spectrum. We identify multiple avoided crossings between impurity- and trimer-like solutions in both the attractive and the repulsive polaron spectra. In particular, the widths of avoided crossings gradually increase as the Fermi superfluid undergoes a crossover from the BCS side towards the BEC side, which suggests instabilities towards three-body losses. Such losses can be reduced for interaction potentials with small effective ranges. We also demonstrate, using the second-order perturbation theory, that the mean-field evaluation of the fermion-impurity interaction energy is inadequate even for small fermion-impurity scattering lengths, due to the essential effects of Fermi superfluid and short-range physics in such a system. Our results are practically useful for cold atom experiments on mixtures.