Properties of the electron-positron plasma created from vacuum in a strong laser field. Quasiparticle excitations

TL;DR

This paper investigates how strong laser fields create electron-positron pairs from vacuum, revealing different regimes of pair production and suggesting conditions for observing the dynamical Schwinger effect.

Contribution

It provides a nonperturbative analysis of vacuum pair creation, identifying regimes with significant pair densities and exploring the electromagnetic structure of the vacuum at short wavelengths.

Findings

Three distinct domains of pair production identified

High-density electron-positron plasma possible in certain regimes

Short-distance vacuum structure influenced by wavelength and field strength

Abstract

Solutions of a kinetic equation are investigated which describe, on a nonperturbative basis, the vacuum creation of quasiparticle electron-positron pairs due to a strong laser field. The dependence of the quasiparticle electron (positron) distribution function and the particle number density is explored in a wide range of the laser radiation parameters, i.e., the wavelength \lambda and amplitude of electric field strength E_0. Three domains are found: the domain of vacuum polarization effects where the density of the e-e+ pairs is small (the "calm valley"), and two accumulation domains in which the production rate of the e-e+ pairs is strongly increased and the e-e+ pair density can reach a significant value (the short wave length domain and the strong field one). In particular, the obtained results point to a complicated short-distance electromagnetic structure of the physical vacuum in the domain of short wavelengths \lambda \lessim \lambda_{acc} = \pi/m. For moderately strong fields E_0 \lesssim E_c=m^2/e, the accumulation regime can be realized where a plasma with a high density of e-e+ quasiparticles can be achieved. In this domain of the field strengths and in the whole investigated range of wavelengths, an observation of the dynamical Schwinger effect can be facilitated.