2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228168Considerable work has been done on the one-loop effective action in combined electromagnetic and gravitational fields, particularly as a tool for determining the properties of light propagation in curved space. After a short review of previous work, I present some recent results obtained using the worldline formalism. In particular, I will discuss various ways of generalizing the QED Euler-Heisenberg Lagrangian to the Einstein-Maxwell case.7 pages, talk given by C. Schubert at XIII Mexican School of Particles and Fields, San Carlos, Mexico, October 2-11, 2008General Relativity and Quantum CosmologyHigh Energy Physics - Theorytext