If we use the path integral approach, can write quantum electrodynamics (QED) in a way that is manifestly relativistic. However integrals are confined to paths on mass-shell. What happens if extend QED by computing over all energy momentum space, not only those mass-shell? We requirement of covariance do this an unambiguous way. This gives where time/energy components appear parallel space/mome...

“In this book Carver Mead offers a radically new approach to the standard problems of electromagnetic theory. Motivated by the belief that the goal of scientific research should be the simplification and unification of knowledge, he describes a new way of doing electrodynamics—collective electrodynamics—that does not rely on Maxwell’s equations, but rather uses the quantum nature of matter as i...

Absolute transition frequencies of the 2s 2S{1/2}→2p2P{1/2,3/2} transitions in Be^{+} were measured for the isotopes ^{7,9-12}Be. The fine structure splitting of the 2p state and its isotope dependence are extracted and compared to results of ab initio calculations using explicitly correlated basis functions, including relativistic and quantum electrodynamics effects at the order of mα(6) and m...