  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.
