Dynamically assisted Sauter-Schwinger effect - non-perturbative versus perturbative aspects

Understand

The Sauter-Schwinger effect predicts the creation of electron-positron pairs out of the quantum vacuum by a strong and slowly varying electric field.

• This effect can be dynamically assisted by an additional weaker time-dependent field, which may drastically enhance the pair-creation probability.
• In previous studies, it has been found that the enhancement may crucially depend on the temporal shape of this weaker pulse, e.g., a Gaussian profile $\exp\{-(\omega t)^2\}$ or a Sauter pulse $1/\cosh^2(\omega t)$ behave quite differently.
• In order to understand this difference, we make a perturbative expansion in terms of the weaker field while treating the strong electric field non-perturbatively.