Radiation matter entanglement
  The quantization of the electromagnetic field in the presence of material bodies, at zero temperature is considered. It is shown that a dielectric does not act as thermal bath for the field and yields a non-trivial non-thermal mixed state of the field. The properties of this state and its entropy are studied. The dependence of the second Renyi entropy of the field on the distance between dispersive objects is shown to decay as R^{-4} for generic bodies. 
Israel Klich
quant-ph cond-mat.stat-mech hep-th