  Relaxation of single defects in a nanometer sized resonator is observed by
coupling surface acoustic waves to a freely suspended beam. The surface waves
act on the resonator as driving forces being able to modify the internal
friction in the beam. In analogy to classical experiments on internal friction
in macroscopic samples, we perform frequency, amplitude, and temperature
dependent experiments on the nano resonator and find a scenario which is
consistent with the observation of single defect relaxation.
