Periodic orbits from the quantum energy spectrum of the wedge billiard

The classical-quantum correspondence is studied for the ‘‘wedge billard,’’ a system known to exhibit hard chaos. The Gutzwiller trace formula is recast as a damped sine or cosine transform, yielding peaks and zero crossings at the values of the actions of the periodic orbits. The lowest 190 energy eigenvalues of the quantum system are shown to contain a great deal of information about the shortest periodic orbits of the classical system.