%0 Journal Article
%T Screened Perturbation Theory to Three Loops
%A Jens O. Andersen
%A Eric Braaten
%A Michael Strickland
%J Physics
%D 2000
%I arXiv
%R 10.1103/PhysRevD.63.105008
%X The thermal physics of a massless scalar field with a phi^4 interaction is studied within screened perturbation theory (SPT). In this method the perturbative expansion is reorganized by adding and subtracting a mass term in the lagrangian. We consider several different mass prescriptions that generalize the one-loop gap equation to two-loop order. We calculate the pressure and entropy to three-loop order and the screening mass to two-loop order. In contrast to the weak-coupling expansion, the SPT-improved approximations appear to converge even for rather large values of the coupling constant.
%U http://arxiv.org/abs/hep-ph/0007159v2