Electron-positron pair creation induced by multi-pulse train of electric fields: effect of randomness in time-delay

TL;DR

This paper studies how random time delays in multi-pulse electric fields affect electron-positron pair creation, revealing that stochastic delays can significantly enhance pair production, especially at the spectrum's center.

Contribution

It introduces the analysis of stochastic time delays in pulse trains and demonstrates their impact on pair creation spectra, highlighting potential for optimizing experimental setups.

Findings

Random delays modify the momentum spectrum's fringe pattern.

Stochastic delays can enhance the central peak of pair distribution.

Nearly tenfold increase in pair production with specific delay fluctuations.

Abstract

We investigate the creation of electron-positron pairs (EPPs) in a sequence of alternating-sign, time-dependent electric field pulse trains by solving the quantum Vlasov equations. Specifically, we focus on Sauter-like pulse trains with random time delays between successive pulses, drawn from a Gaussian distribution wherein the extent of fluctuations is controlled by the standard deviation $\sigma_T$ of the distribution. We find that increasing $\sigma_T$ leads to a dramatic transformation in the longitudinal momentum spectrum. The well-known fringe pattern, akin to that in the multi-slit interference, gets significantly modified. The averaged spectra exhibit a robust Gaussian-like envelope with residual oscillations, which are much more prominent in the central momentum region. Notably, we find that in certain cases, stochastic time delays lead to a pronounced enhancement in the central peak of the distribution function for pulse train containing $N$ pulses. For example, for $N=20$ pulses, $\sigma_T \approx 31$ $[m^{-1}]$(about $17\%$ of the mean time delay) yields nearly a tenfold increase in the central peak, which for $\sigma_T \approx 50$ $[m^{-1}]$ (about $27\%$ of the mean time delay), scales up to $10^3.$ This may open up new possibilities for optimizing multi-pulse field configurations and guide future experimental designs aimed at maximizing EPPs creation.