Collective oscillations in quantum rings: A broken symmetry case

We present calculations within density functional theory of the ground stat e and collective electronic oscillations in small two-dimensional quantum r ings. No spatial symmetries are imposed to the solutions and, as in a recen t contribution, a transition to a broken symmetry solution in the intrinsic reference frame for an increasingly narrow ring is found. The oscillations are addressed by using real-time simulation. Conspicuous effects of the br oken symmetry solution on the spectra are pointed out.