Massive ${\varphi }^4$ Model at Finite Temperature -- Resummayion Procedure la RG Improvement --

Abstract

In this paper the phase structure of the massive $\lambda {\varphi }^4$ model at finite temperature ($T\ne 0$) is investigated by applying a resummation method inspired by the renormalization-group (RG) improvement to the one-loop effective potential. The resummation method a la RG-improvement is shown to work quite succesfully by resumming up systematically large correction-terms of $O(\lambda T/\mu )$ and of $O(\lambda (T/\mu {)}^2)$. The temperature-dependent phase transition of the model is shown to proceed through the second order transition. The critical exponents are determined analytically and are compared with those in other analyses.

Comments: 6 pages, Latex file with sprocl.sty and epsf.sty, including 1 figure (eps.file). Talk presented at 1998 YITP-Workshop on QCD and Hadron Physics. To be published in Proceedings