Affiliation: | IIMAS-UNAM, Apdo. Postal 20-726, Admon. No.~20, Deleg Alvaro Obregon, 01000 Mexico, Mexico Barry Simon ; IIMAS-UNAM, Apdo. Postal 20-726, Admon. No.~20, Deleg Alvaro Obregon, 01000 Mexico, Mexico - Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125 |
Abstract: | We consider examples of rank one perturbations with a cyclic vector for . We prove that for any bounded measurable set , an interval, there exist so that eigenvalue agrees with up to sets of Lebesgue measure zero. We also show that there exist examples where has a.c. spectrum for all , and for sets of 's of positive Lebesgue measure, also has point spectrum in , and for a set of 's of positive Lebesgue measure, also has singular continuous spectrum in . |