Quantum Statistics and Entanglement of Two Electromagnetic Field Modes   Coupled via a Mesoscopic SQUID Ring
  In this paper we investigate the behaviour of a fully quantum mechanical system consisting of a mesoscopic SQUID ring coupled to one or two electromagnetic field modes. We show that we can use a static magnetic flux threading the SQUID ring to control the transfer of energy, the entanglement and the statistical properties of the fields coupled to the ring. We also demonstrate that at, and around, certain values of static flux the effective coupling between the components of the system is large. The position of these regions in static flux is dependent on the energy level structure of the ring and the relative field mode frequencies, In these regions we find that the entanglement of states in the coupled system, and the energy transfer between its components, is strong. 
M. J. Everitt, T. D. Clark, P. Stiffell, H. Prance, R.J. Prance, A.   Vourdas and J. F. Ralph