Observation of Periodic Orbits on Curved Two-Dimensional Geometries
We measure elastomechanical spectra for a family of thin shells. We show that these spectra can be described by a "semiclassical'' trace formula comprising periodic orbits on geodesics, with the periods of these orbits consistent with those extracted from experiment. The influence of periodic orbits on spectra in the case of two-dimensional curved geometries is thereby demonstrated, where the para