Convergence behavior of variational perturbation expansion-- A method for locating Bender-Wu singularities
arXiv:quant-ph/9509005 · doi:10.1016/0375-9601(95)00521-4
Abstract
Variational perturbation expansions have recently been used to calculate directly the strong-coupling expansion coefficients of the anharmonic oscillator. The convergence is exponentially fast with superimposed oscillations, as recently observed empirically by the authors. In this note, the observed behavior is explained and used to determine accurately the magnitude and phase of the leading Bender-Wu singularity which is responsible for the finite convergence radius in the complex coupling constant plane.
Paper texfile convn.tex + figfiles in src (to appear in Phys. Lett. A 205, 101(1995)) Readable in hypertext format under http://www.physik.fu-berlin.de/~kleinert/kleiner_re234/preprint.html See also: http://www.physik.fu-berlin.de/~kleinert/institution.html