Carrier envelope phase and laser pulse shape effects on Schwinger vacuum pair production in super-Gaussian asymmetric electric fields

TL;DR

This paper explores how the carrier envelope phase and laser pulse shape influence electron-positron pair production in asymmetric super-Gaussian electric fields, revealing extreme sensitivity and potential for significant enhancement of pair yields.

Contribution

It provides a detailed analysis of the combined effects of pulse shape and phase on pair production, introducing new insights into optimizing laser parameters for increased pair yields.

Findings

Pair production is highly sensitive to field asymmetry and pulse shape.

Long falling pulses favor multiphoton pair production.

Certain parameters can enhance pair density by 100-300 times.

Abstract

We investigate the combined effects of carrier envelope phase and laser pulse shape on electron-positron pair production in the presence of an external asymmetric super-Gaussian electric field by solving the quantum Vlasov equation. By varying the field asymmetry, the pulse shape from Gaussian to super-Gaussian, and the carrier envelope phase, we show the momentum distribution and the number density of created pairs to exhibit extreme sensitivity to these field characteristics. The effects are also qualitatively explained by analyzing the turning-point structures within the WKB formalism. We observed that multiphoton pair production dominates in the case of long falling-pulse asymmetry. For a short falling pulse with a flat-top super-Gaussian laser profile, pair production is further facilitated. For certain field parameters, we demonstrate that the number density can be enhanced by two to three orders of magnitude.