Reissner-Nordstrom Black Holes in the Inverse Electrodynamics Model
  We study electric and magnetic monopoles in static, spherically symmetric and constant curvature geometries in the context of the inverse electrodynamics model. We prove that this U(1) invariant Lagrangian density is able to support the standard metric of a Reissner-Nordstrom Black Hole, but with more complex thermodynamical properties than in the standard case. By employing the Euclidean Action approach we perform a complete analysis of its phase space depending on the sign and singularities of the heat capacity and the Helmholtz free energy. 
J. A. R. Cembranos (SLAC & Madrid U), A. de la Cruz-Dombriz (Madrid U)   and J. Jarillo (Madrid U)
gr-qc hep-th