G. Besson et al., MULTIPLICITY OF THE FIRST EIGENVALUE OF T HE SCHRODINGER OPERATOR WITH A MAGNETIC-FIELD ON THE 2-SPHERE, Transactions of the American Mathematical Society, 350(1), 1998, pp. 331-345
The purpose of this text is to study the first eigenvalue of Schroding
er operator with magnetic field on the 2-sphere and to show that its m
ultiplicity can be arbitrarily high. We also show that this multiplici
ty is bounded in terms of the curvature of the corresponding connectio
n. This answers a question asked by Y. Colin de Verdiere.