Information-theoretic approach to the convergence of perturbation expansions.

摘要: Two information-theoretic relationships have been derived for assessing the convergence behavior of arbitrary Rayleigh-Schroedinger (RS) perturbation expansions; these provide sensitive global information indices quantitatively estimating rapidity and regularity convergence. The procedure has applied to nine different high-order RS eigenvalue series ground states H/sup -/ He, arising from partitionings Hamiltonian operator same system; our findings order merit are in complete accord with previous numerical theoretical studies. Furthermore, theory an idealized modeled on a geometric progression, thereby gaining insight enabling one correlate actual series; this context, so-called doctrine ''small perturbations'' also investigated, and, corroboration earlier work, it is concluded that unreliable guide selecting favorable Hamiltonian. To knowledge, first time study perturbational