Calculation of functional integrals by means of convergent series and some applications
It is well known that power series in quantum field theory diverge and are nothing but asymptotic expansions in the region of sufficiently small values of coupling constants. We propose a quite different approach to approximative calculation of functional integrals represented by the traditional perturbation theory series. We approximate a functional integral given by the divergent series of the traditional perturbation theory by the sum of finite number of terms of some absolutely convergent series.