发表机构
University of Rochester; Università di Torino; INFN, Sezione di Torino（罗切斯特大学; 都灵大学; 意大利国家核物理研究所都灵分部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究强背景电磁场中量子电动力学（SFQED）的重整化，确认背景场作为电荷重整化，证明其可重整性源于真空QED，并引入新抵消项处理真空感生电磁场的发散。
AI 中文摘要
强背景电磁场中的量子电动力学（SFQED）已在树级层面得到非常详细的研究。除强背景原子场这一显著例外，SFQED 在更高圈阶的研究尚未以相应系统化的方式进行。本文通过将标准的未重整化 SFQED 拉格朗日密度（其与真空 QED 拉格朗日密度的差异在于增加了狄拉克四电流密度与背景四矢量势的相互作用项）用重整化量和抵消项表示，来研究 SFQED 的重整化。在此框架下，我们确认了将背景场作为电荷而非光子场进行重整化的必要性。我们将该方法与另一种采用不同重整化拉格朗日密度的方法进行比较，并证明它们在物理上是等价的。作为副产品，我们将清楚地看到 SFQED 的可重整性直接源于真空 QED 的可重整性。此外，我们得到重整化后的 SFQED 拉格朗日密度相比真空拉格朗日密度包含一个新的抵消项。该抵消项对于重整化电子自能是必要的，因为电子自能相比真空 QED 出现了一个新的贡献，其物理来源是背景电磁场在真空中感生的四电流密度所产生的电磁场。该真空感生电磁场发散，需要被重整化。我们展示了如何在一圈和两圈阶显式实现真空感生电磁场的重整化。所有圈阶的重整化被证明在拉格朗日密度层面更容易推导。最后，我们讨论了自由背景场情形下重整化程序中的一些微妙之处。
英文摘要
Quantum electrodynamics in strong background electromagnetic fields or strong-field QED (SFQED) has been investigated in great detail at the tree level. The study of SFQED at higher loops has not been carried out in a correspondingly systematic way, with the notable exception of strong background atomic fields. Here, we investigate the renormalization of SFQED by writing the standard unrenormalized SFQED Lagrangian density, which differs from the vacuum-QED Lagrangian density by the additional interaction term of the Dirac four-current density with the background four-vector potential, in terms of renormalized quantities and counterterms. Within this framework, we confirm the necessity of renormalizing the background field as an electric charge rather than as a photon field. We compare this approach with an alternative one which features a different renormalized Lagrangian density and we show that they are physically equivalent. As a byproduct, it will become clear that the renormalizability of SFQED directly derives from the renormalizability of vacuum QED. Also, we obtain that the renormalized SFQED Lagrangian density features a new counterterm as compared to the vacuum Lagrangian density. This counterterm is necessary to renormalize the electron self energy, which undergoes a new contribution as compared to vacuum QED, physically due to the electromagnetic field produced by the four-current density induced in the vacuum by the background electromagnetic field. The vacuum-induced electromagnetic field diverges and needs to be renormalized. We show how the renormalization of the vacuum-induced electromagnetic field is implemented explicitly at one loop and at two loops. The renormalization at all loops is shown to be more easily deduced at the level of the Lagrangian density. Finally, some subtleties concerning the renormalization procedure in the case of a free background field.
Comments52 pages, 9 figures
