Dynamical Scaling in Pair Production for Scalar QED

Abstract: We report on the dynamical scaling of momentum spectra for particle-antiparticle pairs at finite times within the framework of scalar Quantum Electrodynamics (QED). The analysis focuses on the momentum spectra in two different choices of adiabatic mode functions, which are related by a Wronskian normalization condition. Oscillations in the momentum spectra are attributed to quantum interference effects in the adiabatic number basis. A novel dynamical scaling behavior emerges when examining the oscillatory momentum spectra of pairs created by a Sauter pulsed field at intermediate times. While the oscillatory spectra are observed at distinct times in the two different choices, they overlap when time is rescaled by the point marking the initiation of the first occurrence of the Residual ParticleAntiparticle Plasma (RPAP) stage (or end of the transient stage) for the central momentum case. This scaling identifies the approximate time at which real particle-antiparticle pair formation becomes possible, shifting the focus from asymptotic times to finite-time dynamics. Additionally, in the multi-photon regime, we find that the momentum spectra exhibit a multi-modal profile structure at finite times, consistent across both choices and also follow the dynamical scaling in this case as well.