An. Sissakian et al., ANALYSIS OF SERIES CONVERGENCE IN VARIATIONAL PERTURBATION-THEORY ANDGAUSSIAN EFFECTIVE POTENTIAL, International journal of modern physics A, 9(11), 1994, pp. 1797-1820
The properties of convergence are studied for the series in the variat
ional perturbation theory for the phi4(d) model. The nonperturbative G
aussian effective potential is derived from a more general approach, t
he variational perturbation theory. Various versions of the variationa
l procedure are explored and the preference of the anharmonic variatio
nal procedure in view of convergence of the obtained series is argued.