We propose a method for the resummation of divergent perturbative expansions in quantum electrodynamics and related field theories. The method is based on a nonlinear sequence transformation and uses as input data only the numerical values of a finite number of perturbative coefficients. The results obtained in this way are for alternating series superiorâ€¦ (More)

We present an improved calculation of higher order corrections to the oneloop self energy of 2P states in hydrogen-like systems with small nuclear charge Z. The method is based on a division of the integration with respect to the photon energy into a high and a low energy part. The high energy part is calculated by an expansion of the electron propagator inâ€¦ (More)