2023/12/28 by Gianluca Degli Esposti, Greger Torgrimsson, Esposti, Gianluca Degli +1 · 3 citations
Physics and Astronomy · Economics, Econometrics and Finance · #Cosmology and Gravitation Theories #Advanced Thermodynamics and Statistical Mechanics #Stochastic processes and financial applications
paper · pdf · doi:10.48550/arxiv.2312.17186
We show how to use a worldline-instanton formalism to calculate, to leading order in the weak-field expansion, the momentum spectrum of nonlinear Breit-Wheeler pair production in fields that depend on time and one spatial coordinate. We find a nontrivial dependence on the width, λ, of the photon wave packet, and the existence of a critical point λc. For λ<λc and a field with one peak, the spectrum has one peak where the electron and positron have the same energy. For λ>λc this splits into two peaks. We calculate a high-energy (Ω≫1) expansion, which to leading order agrees with the results obtained by replacing the space-time field with a plane wave and using the well-known Volkov solutions. We also calculate an expansion for Ω∼ a0≫1, where the field is strong enough to significantly bend the trajectories of the fermions despite Ω≫1.