Effect of symmetrical frequency chirp on pair production

TL;DR

This paper investigates how symmetrical frequency chirp in electric fields influences electron-positron pair production, revealing that increased chirp enhances pair yield and alters momentum spectra, with the dynamically assisted Schwinger mechanism being significant.

Contribution

It introduces a detailed analysis of pair production under symmetrical frequency chirp using Dirac-Heisenberg-Wigner formalism, highlighting the role of chirp symmetry and the dynamically assisted Schwinger mechanism.

Findings

Symmetrical frequency chirp increases pair yield.

Momentum spectra evolve into multi-concentric rings with higher chirp.

Dynamically assisted Schwinger mechanism significantly enhances pair production.

Abstract

By using Dirac-Heisenberg-Wigner formalism we study electron-positron pair production for linear, elliptic, nearly circular and circular polarizations of electric fields with symmetrical frequency chirp, and we obtain Momentum spectra and pair yield. The difference of results among polarized fields is obvious for the small chirp. When the chirp parameter increases, the momentum spectra tend to exhibit the multiphoton pair generation that is characterized by the multi-concentric ring structure. The increase of number density is also remarkable compared to the case of asymmetrical frequency chirp. Note that the dynamically assisted Schwinger Mechanism plays an important role for the enhanced pair production in the symmetrical frequency chirp.