Proposed experimental test of an alternative electrodynamic theory of   superconductors
  An alternative form of London's electrodynamic theory of superconductors predicts that the electrostatic screening length is the same as the magnetic penetration depth. We argue that experiments performed to date do not rule out this alternative formulation and propose an experiment to test it. Experimental evidence in its favor would have fundamental implications for the understanding of superconductivity. 
J. E. Hirsch
cond-mat.supr-con