Polarons in Ultracold Fermi Superfluids
Abstract
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.
Cite
@article{arxiv.1503.04966,
title = {Polarons in Ultracold Fermi Superfluids},
author = {Wei Yi and Xiaoling Cui},
journal= {arXiv preprint arXiv:1503.04966},
year = {2015}
}
Comments
7 pages, 6 figures, updated with the published version