Experimental evidence for non-exponential decay in quantum tunnelling


Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Wilkinson, SR; Bharucha, CF; Fischer, MC; Madison, KW; Morrow, PR; Niu, Q; Sundaram, B; Raizen, MG

Published Date

  • June 5, 1997

Published In

Volume / Issue

  • 387 / 6633

Start / End Page

  • 575 - 577

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/42418

Citation Source

  • Scopus