TY - JOUR

T1 - Total yield of electron-positron pairs produced from vacuum in strong electromagnetic fields

T2 - Validity of the locally constant field approximation

AU - Sevostyanov, D. G.

AU - Aleksandrov, I. A.

AU - Plunien, G.

AU - Shabaev, V. M.

N1 - Publisher Copyright: © 2021 Published by the American Physical Society

PY - 2021/10/14

Y1 - 2021/10/14

N2 - The widely used locally constant field approximation (LCFA) can be utilized in order to derive a simple closed-form expression for the total number of particles produced in the presence of a strong electromagnetic field of a general spatiotemporal configuration. A usual justification for this approximate approach is the requirement that the external field vary slowly in space and time. In this investigation, we examine the validity of the LCFA by comparing its predictions to the results obtained by means of exact nonperturbative numerical techniques. To benchmark the LCFA in the regime of small field amplitudes and low frequencies, we employ a semiclassical approach. As a reference, we consider a standing electromagnetic wave oscillating both in time and space as well as two spatially uniform field configurations: Sauter pulse and oscillating electric field. Performing a thorough numerical analysis, we identify the domain of the field parameters where the approximation is well justified. In particular, it is demonstrated that the Keldysh parameter itself is not a relevant quantity governing the accuracy of the LCFA. It is also found that for field amplitudes close to the Schwinger critical value, the LCFA may overestimate the particle yield. We discuss how this effect is related to the Pauli exclusion principle and quantum interference.

AB - The widely used locally constant field approximation (LCFA) can be utilized in order to derive a simple closed-form expression for the total number of particles produced in the presence of a strong electromagnetic field of a general spatiotemporal configuration. A usual justification for this approximate approach is the requirement that the external field vary slowly in space and time. In this investigation, we examine the validity of the LCFA by comparing its predictions to the results obtained by means of exact nonperturbative numerical techniques. To benchmark the LCFA in the regime of small field amplitudes and low frequencies, we employ a semiclassical approach. As a reference, we consider a standing electromagnetic wave oscillating both in time and space as well as two spatially uniform field configurations: Sauter pulse and oscillating electric field. Performing a thorough numerical analysis, we identify the domain of the field parameters where the approximation is well justified. In particular, it is demonstrated that the Keldysh parameter itself is not a relevant quantity governing the accuracy of the LCFA. It is also found that for field amplitudes close to the Schwinger critical value, the LCFA may overestimate the particle yield. We discuss how this effect is related to the Pauli exclusion principle and quantum interference.

KW - KINETIC DESCRIPTION

KW - LIGHT

UR - http://www.scopus.com/inward/record.url?scp=85117386930&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.104.076014

DO - 10.1103/PhysRevD.104.076014

M3 - Article

AN - SCOPUS:85117386930

VL - 104

JO - Physical review D

JF - Physical review D

SN - 2470-0010

IS - 7

M1 - 076014

ER -