Dresden 2000 – wissenschaftliches Programm

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T: Teilchenphysik

T 508: Höhere Ordnungen

T 508.1: Vortrag

Donnerstag, 23. März 2000, 10:15–10:30, H\,204

QED Effective Action at Finite Temperature: Two-Loop Dominance — •Holger Gies — Institut für theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, 72076 Tübingen

We calculate the two-loop effective action of QED for arbitrary constant electromagnetic fields at finite temperature T in the limit of T much smaller than the electron mass. It is shown that in this regime the two-loop contribution always exceeds the influence of the one-loop part due to the thermal excitation of the internal photon. As an application, we study light propagation and photon splitting in the presence of a magnetic background field at low temperature. We furthermore discover a thermally induced contribution to pair production in electric fields.