Ground State Description of a Single Vortex in an Atomic Fermi gas: From BEC to BCS

S. Giorgini, G. E. Astrakharchik, Jordi Boronat +1 more

Tieling Song, Y. L.

Nicolai Gayle Nygaard, Georg M. Bruun, David L. Feder +2 more

Chih-Chun Chien, Yan He, Qijin Chen +1 more

We use Bogoliubov-de Gennes (BdG) theory to describe a vortex in a neutral fermionic gas, for an attractive interaction that can be arbitrarily tuned to exhibit a crossover from BCS to Bose--Einstein condensation (BEC). We adopt the BCS--Leggett mean-field ground state for which a BdG approach is microscopically justified, and for which a Gross--Pitaevskii description emerges in the BEC limit. The local density of fermionic states is used to provide insight into the particle density depletion from BCS to BEC. We relate this depletion to the presence of unoccupied discrete states at the core center, as well as to a suppression of negative energy continuum states.

Yuki Kawaguchi, Tetsuo Ohmi

We consider a single vortex in a superfluid Fermi gas in the BCS-BEC crossover regime near a Feshbach resonance. The effect of the molecular Bose-Einstein condensate upon the vortex structure is discussed within the mean field approximation at zero temperature. Using the self-consistent Bogoliubov-de Gennes equation of the fermion-boson coupled model, we calculate density distributions of atoms and molecules. As the number of the molecules increases, both atomic and molecular density changes from BCS-like distribution to BEC-like. We also study the change of the vortex core size in the crossover regime.

Giuseppe Tonini, Félix Werner, Yvan Castin