Surface Tension in Unitary Fermi Gases with Population Imbalance
  We study the effects of surface tension between normal and superfluid regions of a trapped Fermi gas at unitarity. We find that surface tension causes notable distortions in the shape of large aspect ratio clouds. Including these distortions in our theories resolves many of the apparent discrepancies among different experiments and between theory and experiments. 
Theja N. De Silva, Erich J. Mueller