Visualization of vortex bound states in polarized Fermi gases at   unitarity
  We analyse theoretically a single vortex in 3D trapped atomic Fermi gases with population polarization near a broad Feshbach resonance. Above a critical polarization the Andreev-like bound states inside the core become occupied for the majority component. As a result, the local density difference at the core center acquires a sudden rise at low temperautres. This provides a visualization of the lowest bound state within the absorption imaging technique. As the polarization increases, the core expands gradually, and correspondingly, the energy of the lowest bound state decreases. 
Hui Hu, Xia-Ji Liu, and Peter D. Drummond