Copper Corrosion

Abstract

For many physical quantities, theory supplies weak- and strong-coupling expansions of the types Σanαn and αpΣbn(α-2 q)n, respectively. Either or both of these may have a zero radius of convergence. We present a simple interpolation algorithm which rapidly converges for an increasing number of known expansion coefficients. The accuracy is illustrated by calculating the ground state energies of the anharmonic oscillator using only the leading large-order coefficient b0 (apart from the trivial zeroth-order expansion coefficient a0 = 1 2). The errors are less than 0.5% for all g. The algorithm is then applied to find energies and masses of the Fröhlich-Feynman polaron. While our energies are very close to Feynman's variational results (although more accurate), our masses are quite different from his, calling for a calculation of at least one more weak- or strong-coupling expansion coefficient to decide which are correct. © 1995.