2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48013It is explained how first-quantized worldline path integrals can be used as an efficient alternative to Feynman diagrams in the calculation of QED amplitudes and effective actions. The examples include the one-loop photon splitting amplitude, the two-loop Euler-Heisenberg Lagrangian, and the one-loop axial vacuum polarization tensor in a general constant electromagnetic field.7 pages, standard latex, no figures, talk given at Workshop on Frontier Tests of Quantum Electrodynamics and Physics of the Vacuum, Sandansky, Bulgaria, June 9-15 1998High Energy Physics - PhenomenologyHigh Energy Physics - Theorytext