title: Universal impurity-induced bound state in topological superfluids.
abstract: We predict a universal midgap bound state in topological superfluids, induced by either nonmagnetic or magnetic impurities in the strong scattering limit. This universal state is similar to the lowest-energy Caroli-de Gennes-Martricon bound state in a vortex core, but is bound to localized impurities. We argue that the observation of such a universal bound state can be a clear signature for identifying topological superfluids. We theoretically examine our argument for a spin-orbit coupled ultracold atomic Fermi gas trapped in a two-dimensional harmonic potential by performing extensive self-consistent calculations within the mean-field Bogoliubov-de Gennes theory. A realistic scenario for observing a universal bound state in ultracold 40K atoms is proposed.
authors: Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122, Australia.
authors: Hui
authors: H
authors: Hu
authors: Lei
authors: L
authors: Jiang
authors: Han
authors: H
authors: Pu
authors: Yan
authors: Y
authors: Chen
authors: Xia-Ji
authors: XJ
authors: Liu