Holographic Fermi Surfaces and Entanglement Entropy
  We argue that Landau-Fermi liquids do not have any gravity duals in the purely classical limit. We employ the logarithmic behavior of entanglement entropy to characterize the existence of Fermi surfaces. By imposing the null energy condition, we show that the specific heat always behaves anomalously. We also present a classical gravity dual which has the expected behavior of the entanglement entropy and specific heat for non-Fermi liquids. 
Noriaki Ogawa, Tadashi Takayanagi and Tomonori Ugajin
hep-th cond-mat.str-el gr-qc