CIRCULAR QUANTUM BILLIARD WITH A SINGULAR MAGNETIC-FLUX LINE

We discuss the application of Gutzwiller's semiclassical theory to a c ircular billiard with a singular magnetic flux line added at its cente r. The Aharonov-Bohm effect manifests itself through the cancellation of periodic orbits for particular flux strengths. Diffraction phenomen a affect the gross-shell structure of the level density and require co rrections of higher order in h. The full quantization of the level spe ctrum, however, is much less affected.