Study on axial fields in the dynamically assisted Schwinger effect

The dynamically assisted Schwinger effect, the generation of fermion-antifermion pairs in vacuum under a strong, slow-varying field and a weak, high-frequency field, has become a promising avenue to probe the vacuum structure and the nonlinear dynamics of QED. However, the role of axial fields in this phenomenon has remained underexplored. This study aims at analyzing how spatial axial fields influence particle production in the dynamically assisted Schwinger effect. Employing the high-frequency effective theory based on the Floquet-Magnus expansion, we demonstrate that a spatial axial field can occur as the effective field of a circular polarized high-frequency plane wave and significantly increase the number of fermions produced across different timescales. This enhancement offers both theoretical insights and useful tools for the experimental implementation of the Schwinger effect.