Strong-Field Breit-Wheeler Pair Production in Two Consecutive Laser Pulses with Variable Time Delay

TL;DR

This study investigates how the time delay between two consecutive intense laser pulses influences electron-positron pair production via the strong-field Breit-Wheeler process, revealing phase effects and dependence on pulse order.

Contribution

It demonstrates the significant impact of pulse timing and order on pair creation probabilities using numerical scalar QED calculations, including analytical insights.

Findings

Time delay strongly affects pair-creation probability.

Relative quantum phase influences interference effects.

Pulse order impacts pair production when pulses differ.

Abstract

Photoproduction of electron-positron pairs by the strong-field Breit-Wheeler process in an intense laser field is studied. The laser field is assumed to consist of two consecutive short pulses, with a variable time delay in between. By numerical calculations within the framework of scalar quantum electrodynamics, we demonstrate that the time delay exerts a strong impact on the pair-creation probability. For the case when both pulses are identical, the effect is traced back to the relative quantum phase of the interfering S-matrix amplitudes and explained within a simplified analytical model. Conversely, when the two laser pulses differ from each other, the pair-creation probability depends not only on the time delay but, in general, also on the temporal order of the pulses.