2021-02-01

UTAPwiki/セミナー/初期宇宙・相対論速報

Dynamically assisted Schwinger effect †

Yusuke Yamada †

Schwinger pair production in electric field background is one of the most well-known non-perturbative effects in quantum field theory. Its non-perturbative nature typically leads to an exponentially small production rate, like tunneling in quantum mechanics.
In this seminar, I will review “dynamically assisted Schwinger effect” where a “perturbative” weak electric field significantly enhances the “non-perturbative” production rate caused by a strong field. This is a very interesting example of interplay between perturbative and non-perturbative effects, and similar mechanism may work in other contexts such as cosmology.

In order to describe the mechanism quantitatively, we have two options, WKB formalism and "world line instanton" method. Although the latter method seems not common in our (cosmology?) group, it gives an interesting description of how perturbative corrections affect non-perturbative pair production. So I will give a brief review of the world line method and discuss the dynamically assisted Schwinger mechanism with such a formalism.
If (and only if) I have time, I will also discuss the dynamical assist mechanism with WKB formalism.

Refs:
R. Schutzhold, H. Gies, G. V. Dunne, Phys.Rev.Lett. 101 (2008) 130404,
G.V. Dunne, C. Schbert, Phys.Rev.D 72 (2005) 105004,
G. Torgrimsson, et al. JHEP 06 (2017) 043
G. Torgrimsson, Phys.Rev.D.99.096002 …etc.