  The correlations of the electrons field-emitted from a superconductor are
fully analyzed, both in space and time. It is proposed that a coincidence
experiment would reveal a positive correlation between the electrons emitted in
opposite directions. The electrons can be entangled and can even violate Bell's
inequality. The crucial role played by Andreev's process is scrutinized,
analytical formulas are derived for the correlations, and the physics behind
the phenomenon is clarified.
