From effective actions to actual effects in QED

Abstract

The construction of low-energy effective actions in QED for several types of external conditions is reviewed. Emphasis is put on the application of these effective actions to a variety of physical effects which represent a manifestation of vacuum polarization. Soft-photon interactions with external electromagnetic fields and/or a heat bath are described, pair production at finite temperature is discussed, and finally a glance at photon-neutrino interactions is provided.Comment: 15 pages, 5 figures, Talk given at "QED 2000", the 2nd workshop on frontier tests of quantum electrodynamics and physics of the vacuum, Trieste, Italy, Oct. 5-11, 200