The entanglement entropy of one-dimensional gases
  We introduce a systematic framework to calculate the bipartite entanglement entropy of a spatial subsystem in a one-dimensional quantum gas which can be mapped into a noninteracting fermion system. To show the wide range of applicability of the proposed formalism, we use it for the calculation of the entanglement in the eigenstates of periodic systems, in a gas confined by boundaries or external potentials, in junctions of quantum wires and in a time-dependent parabolic potential. 
Pasquale Calabrese, Mihail Mintchev and Ettore Vicari
cond-mat.stat-mech cond-mat.quant-gas quant-ph