Uncovering spectral repulsion in extended quasienergy states

Abstract
We study classical and quantum mechanics of a rotor in the presence of two interacting nonlinear resonances. Quasienergy states and quasienergies are computed. The widths of the quasienergy states in the representation of the unperturbed angular-momentum levels are found to be closely associated with the classical dynamics. The widths of many resonant quasienergy states are found to be extended by the quantum-resonance overlap when the perturbation is increased. Spectral repulsion is present in these extended states.