Spin-dependent dynamically assisted Schwinger mechanism

• Published in: Physical review. D 2019-07, Vol.100 (1), p.016013
• Main Authors: Huang, Xu-Guang, Taya, Hidetoshi
• Format: Article
• Language: English
• Subjects: Critical field (superconductivity); Dirac equation; Electric fields; Field strength; Pair production; Particle spin; Perturbation theory
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.100.016013

We study electron and positron pair production from the vacuum by a strong slow electric field superimposed by a weak fast electric field pointing in an arbitrary direction as a perturbation (the dynamically assisted Schwinger mechanism). An analytical formula for the production number is derived on the basis of the perturbation theory in the Furry picture. The formula is found to be in good agreement with nonperturbative results obtained by numerically solving the Dirac equation if the perturbation is sufficiently weak and/or is not very slow. We also find analytically/numerically that the Schwinger mechanism becomes spin dependent if the perturbation has a transverse component with respect to the strong electric field. The number difference between spin-up and -down particles is strongly suppressed by an exponential of the critical field strength if the frequency of the perturbation is small, while it is only weakly suppressed by powers of the critical field strength if the frequency is large enough. We also find that the spin imbalance exhibits nontrivial oscillating behaviors in terms of the frequency of the perturbation, the azimuthal angle, and the momentum of produced particles.