Dirac quantization condition with the superconducting state
  The author argues that the Dirac quantization condition might imply the existence of an undiscovered electromagnetic structure which governs the quantization of the electric charge and the quantization of the magnetic flux in the superconducting state. An experimental set-up which can provide a strong evidence by predicting the discrimination between the magnetic flux generated by the positive and negative electric charge in the superconducting state is also proposed. 
Jer Yu Lin