论文标题
在强电磁场中由真空产生的电子峰值对的总产率：局部恒定场近似的有效性
Total yield of electron-positron pairs produced from vacuum in strong electromagnetic fields: validity of the locally constant field approximation
论文作者
论文摘要
可以利用广泛使用的局部恒定场近似（LCFA），以得出一个简单的闭合形式表达，用于在存在的一般时空构型的强电磁场中产生的颗粒总数。这种近似方法的通常理由是，外部场在时空和时间上的变化缓慢。在这项研究中，我们通过将LCFA的预测与通过确切的非扰动数值技术获得的结果进行比较，来检查LCFA的有效性。为了基准在小场幅度和低频方面基准LCFA，我们采用了一种半经典方法。作为参考，我们考虑了站立电磁波在时间和空间上都在振荡，以及两个空间均匀的场合构型：空组脉冲和振荡电场。进行彻底的数值分析，我们确定了近似值是合理的场参数的域。特别是，证明Keldysh参数不是管理LCFA准确性的相关数量。
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 spatio-temporal 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 is not a relevant quantity governing the accuracy of the LCFA.
