Evidence for Quantized Displacement in Macroscopic Nanomechanical   Oscillators
  We report the observation of discrete displacement of nanomechanical oscillators with gigahertz-range resonance frequencies at millikelvin temperatures. The oscillators are nanomachined single-crystal structures of silicon, designed to provide two distinct sets of coupled elements with very low and very high frequencies. With this novel design, femtometer-level displacement of the frequency-determining element is amplified into collective motion of the entire micron-sized structure. The observed discrete response possibly results from energy quantization at the onset of the quantum regime in these macroscopic nanomechanical oscillators. 
Alexei Gaidarzhy, Guiti Zolfagharkhani, Robert L. Badzey, and Pritiraj   Mohanty