In the quantum kinetic framework, we investigate the momentum spectrum and the number density of created electron-positron pairs from vacuum in the combined electric fields composed of two sets of alternating-sign electric field pulse trains, a strong but slowly varying one and a weak but rapidly changing one. It is found that the pair production can be strongly enhanced by combining the multiple-slit interference effect with the dynamically assisted Schwinger mechanism. By considering the contribution of the transverse momentum, we find that the number density of created particles depends linearly on the electric field pulse number, i.e., a power law with index 1. Moreover, we study the effect of interpulse time delay on pair production and find that the number density is very sensitive to the interpulse time delay. The symmetry of the momentum spectrum for an $N$-pulse electric field and the difference of the multiple-slit interference effect between the nonperturbative Schwinger mechanism and the perturbative multiphoton electron-positron pair creation are also studied. Some possible explanations for observed results of momentum spectrum and number density are also given and discussed.

• Received 13 March 2014

DOI:https://doi.org/10.1103/PhysRevD.89.093011