Entanglement Entropy as a Probe of the Proximity Effect in Holographic   Superconductors
  We study the entanglement entropy as a probe of the proximity effect of a superconducting system by using the gauge/gravity duality in a fully back-reacted gravity system. While the entanglement entropy in the superconducting phase is less than the entanglement entropy in the normal phase, we find that near the contact interface of the superconducting to normal phase the entanglement entropy has a different behavior due to the leakage of Cooper pairs to the normal phase. We verify this behavior by calculating the conductivity near the boundary interface. 
Xiao-Mei Kuang, Eleftherios Papantonopoulos and Bin Wang
hep-th cond-mat.supr-con