2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/226935The optimized expansion is used to formulate a systematic approximation scheme to the probability distribution of a stochastic system. The first order approximation for the one-dimensional system driven by noise in an anharmonic potential is shown to agree well with the exact solution of the Fokker-Planck equation. Even for a bistable system the whole period of evolution to equilibrium is correctly described at various noise intensities.12 pages, LATEX, 3 Postscript figures compressed andStatistical MechanicsHigh Energy Physics - Theorytext