Bound states of a localized magnetic impurity in a superfluid of paired ultracold fermions

Eric Vernier, David Pekker, Martin W. Zwierlein, Eugene Demler
2011 Physical Review A. Atomic, Molecular, and Optical Physics  
We consider a localized impurity atom that interacts with a cloud of fermions in the paired state. We develop an effective scattering length description of the interaction between an impurity and a fermionic atom using their vacuum scattering length. Treating the pairing of fermions at the mean-field level, we show that the impurity atom acts like a magnetic impurity in the condensed matter context, and leads to the formation of a pair of Shiba bound states inside the superconducting gap. In
more » ... ition, the impurity atom can lead to the formation of deeply bound states below the Fermi sea.
doi:10.1103/physreva.83.033619 fatcat:6xlsyfiwq5awjfwkin4bif6nki