Sauter-Schwinger effect in a Bardeen-Cooper-Schrieffer superconductor

TL;DR

This paper predicts a superconducting analog of the Schwinger effect, where intense electric fields create coherent quasiparticle excitations from the ground state, revealing new interactions between superconductivity and electric fields.

Contribution

It introduces the concept of a superconducting Schwinger effect, linking quantum field theory phenomena with superconducting quasiparticles and proposing experimental verification methods.

Findings

Electrostatic fields can generate coherent quasiparticle pairs in superconductors.

The superconducting state is weakened by the creation of these excitations.

The phenomenon offers new insights into superconductor-electric field interactions.

Abstract

From the sixties a deep and surprising 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. Here we follow further this parallelism and show that it predicts an outstanding phenomenon: the superconducting Schwinger effect (SSE). As in the quantum electrodynamics Schwinger effect, where an electron-positron couple is created from the vacuum by an intense electric field, we show that an electrostatic field can generate two coherent excitations from the superconducting ground-state condensate. Differently from the dissipative thermal excitation, these form a new macroscopically coherent and dissipationless state. We discuss how the superconducting state is weakened by the creation of this kind of excitations. In addition to shed a different light and suggest a method for the experimental verification of the Schwinger effect, our results pave the way to the understanding and exploitation of the interaction between superconductors and electric fields.