Philippe Briet, Horia Cornean
Locating the spectrum for Schroedinger and Dirac operators
(280K, Postscript)
ABSTRACT. Some spectral properties of magnetic Schroedinger and Dirac operators perturbed by long range magnetic fields are investigated. If the intensity of the field is small enough, a better location of the
perturbed spectrum is given.
In particular, if the unperturbed spectrum is discrete, we show that the perturbed eigenvalues are given in terms of an absolutely convergent series with respect to a magnetic parameter, from which the usual asymptotic expansion can be derived.