Large order asymptotics and convergent perturbation theory for critical indices of the $\phi ^4$ model in ${4-\epsilon}$ expansion

Abstract

Large order asymptotic behaviour of renormalization constants in the minimal subtraction scheme for the $\phi ^4$ $(4-\epsilon)$ theory is discussed. Well-known results of the asymptotic $4-\epsilon $ expansion of critical indices are shown to be far from the large order asymptotic value. A {\em convergent} series for the model $\phi ^4$ $(4-\epsilon)$ is then considered. Radius of convergence of the series for Green functions and for renormalisation group functions is studied. The results of the convergent expansion of critical indices in the $4-\epsilon $ scheme are revalued using the knowledge of large order asymptotics. Specific features of this procedure are discussed.