Exact results for the entanglement across defects in critical chains
  We consider fermionic and bosonic quantum chains where a defect separates two subsystems and compare the corresponding entanglement spectra. With these, we calculate their R\'enyi entanglement entropies and obtain analytical formulae for the continuously varying coefficient of the leading logarithmic term. For the bosonic case we also present numerical results. 
Ingo Peschel and Viktor Eisler
cond-mat.stat-mech