Nonrelativistic Quantum Electrodynamics: Leading Radiative Corrections

An effective field theory is constructed to describe low-energy processes in quantum electrodynamics-nonrelativistic quantum electrodynamics (NRQED). It is shown how the NRQED formalism makes it possible to develop a rigorous perturbation theory for calculating higher-order corrections in parameters v/c similar to Z alpha, beta = m/M, where v is the speed of electrons (muons) in atoms, and m/M is the ratio of masses of light particles to those of heavy ones in a molecular system. As an example, the leading radiation correction of order m alpha(Z alpha)(4) is calculated. It is shown how the regularization parameter introduced into NRQED cancels in the final expression for the energy without leading to meaningless infinite results.