Total yield of electron-positron pairs produced from vacuum in strong electromagnetic fields: validity of the locally constant field approximation
arXiv:2012.10751 · doi:10.1103/PhysRevD.104.076014
Abstract
The widely-used locally constant field approximation (LCFA) can be utilized in order to derive a simple closed-form expression for the total number of particles produced in the presence of a strong electromagnetic field of a general spatio-temporal configuration. A usual justification for this approximate approach is the requirement that the external field vary slowly in space and time. In this investigation, we examine the validity of the LCFA by comparing its predictions to the results obtained by means of exact nonperturbative numerical techniques. To benchmark the LCFA in the regime of small field amplitudes and low frequencies, we employ a semiclassical approach. As a reference, we consider a standing electromagnetic wave oscillating both in time and space as well as two spatially uniform field configurations: Sauter pulse and oscillating electric field. Performing a thorough numerical analysis, we identify the domain of the field parameters where the approximation is well justified. In particular, it is demonstrated that the Keldysh parameter is not a relevant quantity governing the accuracy of the LCFA.
References in corpus (11)
- Worldline Instantons II: The Fluctuation Prefactor
- Momentum signatures for Schwinger pair production in short laser pulses with a sub-cycle structure
- The Stokes Phenomenon and Schwinger Vacuum Pair Production in Time-Dependent Laser Pulses
- Interference Effects in Schwinger Vacuum Pair Production for Time-Dependent Laser Pulses
- The Schwinger mechanism revisited
- Pair Production Beyond the Schwinger Formula in Time-Dependent Electric Fields
- Multidimensional Worldline Instantons
- Electron-positron pair production in a bifrequent oscillating electric field
- Momentum distribution of particles created in space-time-dependent colliding laser pulses
- Pulse shape effects on the electron-positron pair production in strong laser fields
- Landau-Zener-Stückelberg interferometry in pair production from counterpropagating lasers