• DOI:10.1038/42418
• Corpus ID: 4246387

Experimental evidence for non-exponential decay in quantum tunnelling

@article{Wilkinson1997ExperimentalEF,
  title={Experimental evidence for non-exponential decay in quantum tunnelling},
  author={Steven R. Wilkinson and C. F. Bharucha and Martin C. Fischer and Kirk W. Madison and P. R. Morrow and Q. Niu and Bala Sundaram and Mark Raizen},
  journal={Nature},
  year={1997},
  volume={387},
  pages={575-577}
}

• S. Wilkinson, C. Bharucha, +5 authors M. Raizen
• Published 5 June 1997
• Physics
• Nature

An exponential decay law is the universal hallmark of unstable systems and is observed in all fields of science. This law is not, however, fully consistent with quantum mechanics and deviations from exponential decay have been predicted for short as well as long times. Such deviations have not hitherto been observed experimentally. Here we present experimental evidence for short-time deviation from exponential decay in a quantum tunnelling experiment. Our system consists of ultra-cold sodium atoms that are trapped in an accelerating periodic optical potential created by a standing wave of light. Atoms can escape the wells by quantum tunnelling, and the number that remain can be measured as a function of interaction time for a fixed value of the well depth and acceleration. We observe that for short times the survival probability is initially constant before developing the characteristics of exponential decay. The conceptual simplicity of the experiment enables a detailed comparison with theoretical predictions.