The efficiency of the Flory approximation

Abstract

The Flory approximation (1969) for the self-avoiding chain problem is compared with a conventional perturbation theory expansion. While in perturbation theory each term is averaged over the unperturbed set of configurations, the Flory approximation is equivalent to the perturbation theory with the averaging over the stretched set of configurations. This imposes restrictions on the integration domain in higher-order terms and they can be treated self consistently. The accuracy delta nu / nu of the Flory approximation for self-avoiding chain problems is estimated to be 10^-1-10^-2 for 1<d<4.