Zachary Harris, Department of Physics, University of Connecticut

Resurgence in QED: Probing the Schwinger effect in inhomogeneous fields

The structure of the QED vacuum is a subject of great interest, especially as experiments begin to more directly probe the non-linear regime of the theory. One of the most striking features of the vacuum is its polarization in the presence of an electric field — a non-perturbative phenomenon that leads to pair production. Detailed information about this non-perturbative structure is contained in the divergence of perturbation theory, which is more generally described by the theory of resurgence. We study the one-loop QED effective action for an exactly solvable, inhomogeneous background field configuration and use Borel summation to illustrate the connection between perturbative and non-perturbative regimes. Using only 15 terms in the weak magnetic field perturbative expansion, we extrapolate to both strong magnetic field and electric field configurations and obtain a pair-production rate that agrees with the exact effective action to remarkable precision.