Sauter-Schwinger effect in superconductors

 From the sixties, a deep connection has followed the development of 
superconductivity and quantum field theory. The Anderson-Higgs mechanism 
and the similarities between the Dirac and Bogoliubov-de Gennes 
equations are the most intriguing examples. In this last analogy, the 
massive Dirac particle is identified with a quasiparticle excitation and 
the fermion mass-energy with the superconducting gap energy. I will show 
that, following this parallelism, it is possible to predict a new 
phenomenon: the superconducting Schwinger effect. As in the quantum 
electrodynamics Schwinger effect, where an electron-positron couple is 
created from the vacuum by an intense electric field, an electrostatic 
field can generate two coherent excitations from the superconducting 
ground-state condensate. These excitations are crucially different from 
the ones usually observed in superconductors and should lead to the 
weakening of superconductivity.
I will discuss the connection with recent experiments and future 
developments inspired by the original Schwinger paper.