ABSTRACT
This Chapter presents in detail some applications of the concepts developed in the theory of QED: (i) The electron scattering in an external field, and the associated issues arising from the emission of low-energy photons (bremsstrahlung) and the consequent occurrence of infrared divergences (ii) Bethe's calculation of the Lamb Shift in the hydrogen atom; (iii) the Vacuum Polarisation to order https://www.w3.org/1998/Math/MathML" display="inline"> α ; (iv) The anomalous magnetic moment of the electron. The agreement between the results of these calculations and the experimental data has confirmed unequivocally the validity of QED and, more generally, the concepts which are at the foundations of quantum field theory.
