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QED Effective Action at Finite Temperature: Two-Loop Dominance

Holger Gies
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Abstract

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.

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Holger Gies. 1999-09-24. QED Effective Action at Finite Temperature: Two-Loop Dominance. https://doi.org/10.1103/physrevd.61.085021

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