Application of a light-front coupled-cluster method to quantum   electrodynamics
  A field-theoretic formulation of the exponential-operator technique is applied to a Hamiltonian eigenvalue problem in electrodynamics, quantized in light-front coordinates. Specifically, we consider the dressed-electron state, without positron contributions but with an unlimited number of photons, and compute its anomalous magnetic moment. A simple perturbative solution immediately yields the Schwinger result of alpha/2pi. The nonperturbative solution, which requires numerical techniques, sums a subset of corrections to all orders in alpha and incorporates additional physics. 
S. S. Chabysheva
hep-ph