title: Three-loop critical exponents, amplitude functions, and amplitude ratios from variational perturbation theory.
abstract: We use variational perturbation theory to calculate various universal amplitude ratios above and below Tc in minimally subtracted straight phi4 theory with N components in three dimensions. In order to best exhibit the method as a powerful alternative to Borel resummation techniques, we consider only two- and three-loops expressions where our results are analytic expressions. For the critical exponents, we also extend existing analytic expressions for two loops to three loops.
authors: Institut für Theoretische Physik, Arnimallee 14 D-14195 Berlin, Germany.
authors: H
authors: H
authors: Kleinert
authors: B
authors: B
authors: Van den Bossche