Fermionic entanglement in itinerant systems
  We study pairwise quantum entanglement in systems of fermions itinerant in a lattice from a second-quantized perspective. Entanglement in the grand-canonical ensemble is studied, both for energy eigenstates and for the thermal state. Relations between entanglement and superconducting correlations are discussed in a BCS-like model and for $\eta$-pair superconductivity. 
Paolo Zanardi, Xiaoguang Wang (Institute for Scientific Interchange   (ISI) Foundation)