Could the Casimir Effect explain the Energetics of High-Temperature   Superconductors?
  It is proposed that the Casimir energy of the electromagnetic field in between the layers of cuprate superconductors could significantly contribute to the energy balance in these materials. Since the Casimir energy is strongly dependent on the distance between the layers a corresponding dependence is predicted for the superconducting transition temperatures. Comparison with the experimental data on the transition temperatures of epitaxial superlattices of alternating layers of YBCO and PrBCO of varying thickness shows that these are well reproduced. 
Achim Kempf