Descripción
For decades, extracting N-photon amplitudes from effective actions remained a significant algebraic challenge, often requiring the evaluation of numerous Feynman diagrams and complex Dirac traces. In this talk, we demonstrate how the Worldline Formalism transforms these 'brute-force' computations into a streamlined and elegant procedure. Using the one-loop Master Formula, we show that N-photon amplitudes are generated from a single path integral, bypassing the need for individual diagrams and providing a non-local representation valid at all energy scales. We illustrate the efficiency of this method through the computation of the low-energy limit, as well as the specific 2-photon and 4-photon cases.
