Entanglement properties in the Inhomogeneous Tavis-Cummings model
  In this work we study the properties of the atomic entanglement in the eigenstates spectrum of the inhomogeneous Tavis-Cummings Model. The inhomogeneity is present in the coupling among the atoms with quantum electromagnetic field. We calculate analytical expressions for the concurrence and we found that this exhibits a strong dependence on the inhomogeneity. 
C. E. L\'opez, F. Lastra, G. Romero and J. C. Retamal