A brief introduction to nonperturbative calculations in light-front QED

A nonperturbative method for the solution of quantum field theories is described in the context of quantum electrodynamics and applied to the calculation of the electron's anomalous magnetic moment. The method is based on light-front quantization and Pauli-Villars regularization. The application to light-front QED is intended as a test of the methods in a gauge theory, as a precursor to possible methods for the nonperturbative solution of quantum chromodynamics. The electron state is truncated to include at most two photons and no positrons in the Fock basis, and the wave functions of the dressed state are used to compute the electrons's anomalous magnetic moment. A choice of regularization that preserves the chiral symmetry of the massless limit is critical for the success of the calculation.Comment: 7 pages, 5 figures, RevTeX 4.1; to appear in the proceedings of QCD@Work 2010, Martina Franca, Italy, June 20-2

An illustration of the light-front coupled-cluster method in quantum electrodynamics

A field-theoretic formulation of the exponential-operator technique is applied to a nonperturbative 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/2\pi. The nonperturbative solution, which requires numerical techniques, sums a subset of corrections to all orders in \alpha\ and incorporates additional physics.Comment: 6 pages, 1 figure; RevTeX 4.1; presented at QCD@Work2012, the International Workshop on QCD Theory and Experiment, June 18-21, 2012, Lecce, Ital