Approximation methods for many-electron atoms from a field theory point of view

Abstract

A summary of a field-theoretic approach to the study of the energies and radiative transition matrix elements of many-electron atoms is presented. The approach can deal with both non-relativistic and relativistic atoms. The method provides a unified description of a number of well-known approximations for calculating energy eigenvalues, and can easily be generalized to include new types of approximations and higher order correlations. Insistence on gauge invariance of transition amplitudes at every level of approximation leads to a generalization of the previously used Hartree-Fock results for transition amplitudes. It involves non-local effective currents.