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The Schrödinger equation as a singular perturbation problem

Published online by Cambridge University Press:  14 November 2011

E. M. de Jager
Affiliation:
Department of Mathematics, University of Amsterdam, Netherlands
T. Küpper
Affiliation:
Department of Mathematics, University of Cologne, Germany

Synopsis

Comparisons have been made of the eigenvalues and the corresponding eigenfunctions of the eigenvalue problems

and

with φ ∈ C(-∞, +∞) and 0≦φ(x)≦C|x|i+1(1+|x|1), −∞<x<+∞ where i and l are arbitrary positive numbers with i≧2k≧2, k integer. In first approximation the eigenvalues λ and λ and the corresponding eigenfunctions ψ and ψ are the same for ε→0; the error decreases whenever the exponent i increases.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1978

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References

1Eckhaus, W.. Matched asymptotic expansions and singular perturbations (Amsterdam: North Holland, 1973).Google Scholar
2Imada, N.. An asymptotic solution of a second order linear differential equation. J. Math. Anal. Appl. 52 (1975), 322343.CrossRefGoogle Scholar
3Giertz, M.. On the solutions in L 2(-∞, +∞) of y n + (λ-q(x)) y = 0 when q is rapidly increasing. Proc. London Math. Soc. 14 (1964), 5373.CrossRefGoogle Scholar
4Kato, T.. Perturbation theory for linear operators (Berlin: Springer, 1976).Google Scholar
5Kemble, E.. The fundamental principles of quantum mechanics (New York: Dover, 1937).Google Scholar
6Pitts, C. G. C.. Asymptotic approximations to solutions of a second-order differential equation. Quart. J. Math. Oxford Ser. 17 (1966), 307320.Google Scholar
7Pitts, C. G. C.. Simplified asymptotic approximations to solutions of a second-order differential equation. Quart. J. Math. Oxford Ser. 21 (1970), 223242.CrossRefGoogle Scholar
8Pitts, C. G. C.. On eigenfunction expansions for a positive potential function increasing slowly to infinity. J. Differential Equations, 13 (1973), 358373.CrossRefGoogle Scholar
9Titchmarsh, E. C.. Eigenfunction expansions associated with second order differential equations I (Oxford: Clarendon Press, 1962).Google Scholar
10Titchmarsh, E. C.. Eigenfunction expansions associated with second order differential equations II (Oxford: Clarendon Press, 1958).Google Scholar
11Titchmarsh, E. C.. On the asymptotic distribution of eigenvalues. Quart. J. Math. Oxford Ser. 5 (1954), 228240.CrossRefGoogle Scholar
12Weinstein, A. and Stenger, W.. Methods of intermediate problems for eigenvalues (London: Academic Press, 1972).Google Scholar