FREE-ENERGY OF HIGH-TEMPERATURE QED TO ORDER E(5) FROM EFFECTIVE-FIELD THEORY

Massless quantum electrodynamics is studied at high temperature and ze ro chemical potential. We compute the Debye screening mass squared and the free energy to order e(5) by an effective field theory approach, recently developed by Braaten and Nieto. Our results are in agreement with calculations done in resummed perturbation theory. This method ma kes it possible to separate contributions to the free energy from thos e to different momentum scales (order T and eT) and provides an econom ical alternative to computations in the full theory which involves the dressing of bosonic propagators.