Role of the spatial inhomogeneity on the laser-induced vacuum decay

This study suggests that the unavoidable spatial inhomogeneity of intense electromagnetic fields has a drastic effect on the electron-positron pair-creation process from the vacuum. We use the example of the Breit-Wheeler process, where the collision of two gamma-ray photons is predicted to create electron-positron pairs, to show that the multiphoton pair-creation process cannot be modeled by solutions to the Dirac equation under time-periodic fields that are spatially homogeneous. The neglect of the spatial inhomogeneity leads here to spurious energy spectra and misleading pair-creation yields that can be incorrect by several orders of magnitude. This finding is surprising as there are many widely cited works where the laser is modeled by a spatially homogeneous alternating electric field.