The pressure of QED from the two-loop 2PI effective action

摘要

We compute the pressure of hot quantum electrodynamics from the two-loop truncation of the 2PI effective action. Since the 2PI resummation guarantees gauge-fixing independence only up to the order of the truncation, our result for the pressure presents a gauge-dependent contribution of O(e(4)). We numerically characterize the credibility of this gauge-dependent calculation and find that the uncertainty due to gauge parameter dependence is under control for xi less than or similar to 1. Our calculation also suggests that the choice of Landau gauge may minimize gauge-dependent effects. (C) 2008 Elsevier B.V. All rights reserved.