ABSTRACT
There are a number of different ways to test Quantum Electrodynamics. The most important of these have to do with measurements of scattering processes, anomalous magnetic moments, atomic energy level shifts, and changes in the coupling strength. All charged objects with angular momenta have magnetic moments, so we expect electrons to also have magnetic moments. Seventy-two Feynman diagrams are needed for the third term, and all of them have been evaluated exactly using symbolic manipulation programs on computers, after nearly thirty years of hard work. The fourth term requires the evaluation of 891 four-loop Feynman diagrams, and has been estimated numerically using large-scale computations on supercomputers. The uncertainty on the Standard Model theoretical values is dominated by the uncertainty on the lowest-order hadronic vacuum polarization.
