To supplement Huby's rules in the Rayleigh-Schrödinger perturbation theory of non-degenerate discrete levels, an expression for the total number of terms contained in the n th order is derived. The number of terms in the n th order having v + 1 disconnected factors is also found.

Proceedings of the Physical SocietyNov 1, 196215 citations

Analytical results for state-to-state transition probabilities in the multistate Landau-Zener model by nonstationary perturbation theory

M. V. Volkov, Valentin N. Ostrovsky

Multistate generalizations of Landau-Zener model are studied by summing entire series of perturbation theory. A technique for analysis of the series is developed. Analytical expressions for probabilities of survival at the diabatic potential curves with extreme slope are proved. Degenerate situations are considered when there are several potential curves with extreme slope. Expressions for some state-to-state transition probabilities are derived in degenerate cases.

arXiv:cond-mat/0611046Physical Review AFeb 20, 200717 citations