Dual Axion Electrodynamics
  The duality relation between the electric and magnetic fields, in the presence of an additional axion-like field, is considered. We derive the new equations that describe the electrodynamics in this model, and we discuss the implications for the conservation of the electric and magnetic four-currents and for the propagation of waves. 
Luca Visinelli
physics.gen-ph physics.class-ph