Comment on "Density and Spin response of a strongly-interacting Fermi   gas in the attractive and quasi-repulsive regime"
  This is a comment on Phys. Rev. Lett. 108, 080401 (2012) by Palestini et al. We pointed out that the diagrammatic method in that article violates gauge invariance. As a consequence, there will a Meissner effect in the normal phase and the contribution from collective modes are not mentioned in the symmetry-broken phase. 
Chi-Chun Chien, Hao Guo, K. Levin
cond-mat.quant-gas cond-mat.supr-con