Abstract
In this work we study the behavior of embedded eigenvalues of Sturm-Liouville problems in the half axis under local perturbations. When the derivative of the spectral function is strictly positive, we prove that the embedded eigenvalues either disappear or remain fixed. In this case we show that local perturbations cannot add eigenvalues in the continuous spectrum. If the condition on the spectral function is removed then a local perturbation can add infinitely many eigenvalues.
Similar content being viewed by others
References
Agmon, S., Herbst, I., Skibsted, E.: Perturbation of embedded eigenvalues in the generalizedN-Body problem. Comm. Math. Phys.122, 411–438 (1989)
Aronszajn, N.: On a problem of Weyl in the theory of Singular Sturm-Liouville equations. Am. J. Math.79, 597–610 (1957)
del Río Castillo, R.R.: Instability of the absolutely continuous spectrum of ordinary differential operators under local perturbations. J. Math. Anal. Appl.142, (2) (1989)
del Río Castillo, R.R.: Dissertation, Frankfurt am Main 1985
del Río Castillo, R.R.: Singular spectrum of Sturm-Liouville operators under local perturbations. Am. J. Math.113, 203–217 (1990)
Eastham, M.S.P., Kalf, H.: Schrödinger-type operators with continuous spectra. Boston, London, Melbourne: Pitman Press
Jörgens, K.: Spectral theory of second order ordinary differential operators. Lectures delivered at Aarhus Universitet, 1962/63
Levitan, B.M.: Inverse Sturm-Liouville problems. Utrecht, The Netherlands: VNU Science Press, 1987
Naimark, M.A.: Linear differential operators. Part II. New York: Ungar, 1967
Weidmann, J.: Spectral theory of ordinary differential operators. Lecture Notes in Mathematics, Vol. 1258. Berlin, Heidelberg, New York: Springer 1987
Author information
Authors and Affiliations
Additional information
Communicated by B. Simon
Rights and permissions
About this article
Cite this article
del Río Castillo, R.R. Embedded eigenvalues of Sturm Liouville operators. Commun.Math. Phys. 142, 421–431 (1991). https://doi.org/10.1007/BF02102068
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02102068