ABSTRACT
In this chapter we will apply the methods developed in previous chapters to the construction of a perturbation theory applicable to quantum electrodynamics, the theory of interactions between electrons, described by the Dirac field, and the electromagnetic field. This system is described by the Lagrangian L = ψ ¯ i γ μ ( ∂ μ - i e 0 A μ ) - m 0 ψ - 1 4 F μ ν F μ ν . $$ \begin{aligned} \mathcal L = \bar{\psi }\left[ i\gamma ^{\mu }(\partial _{\mu }-ie_{0}A_{\mu })-m_{0}\right]\psi -\frac{1}{4}F^{\mu \nu }F_{\mu \nu } \ . \end{aligned} $$ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315369723/48d43afe-85b0-4e2b-a932-df2bd1af07be/content/math10_447.tif"/>
