Quantum gravitational decoherence of matter waves

Charle H-T Wang, Robert Bingham, J Tito Mendonça

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One of the biggest unsolved problems in physics is the unification of quantum mechanics and general relativity. The lack of experimental guidance has made the issue extremely evasive, though various attempts have been made to relate the loss of matter wave coherence to quantum spacetime fluctuations. We present a new approach to the gravitational decoherence near the Planck scale, made possible by the recently discovered conformal structure of canonical gravity. This leads to a gravitational analogue of Brownian motion whose correlation length is given by the Planck length up to a scaling factor. With input from recent matter wave experiments, we show the minimum value of this factor to be well within the expected range for quantum gravity theories. This suggests that the sensitivities of advanced matter wave interferometers may be approaching the fundamental level due to quantum spacetime fluctuations, and that investigating Planck scale physics using matter wave interferometry may become a reality in the near future.
Original languageEnglish
Pages (from-to)L59-L65
Number of pages7
JournalClassical and Quantum Gravity
Issue number18
Early online date18 Aug 2006
Publication statusPublished - 21 Sep 2006


  • quantum mechanics
  • relativity
  • gravitational decoherence
  • gravity
  • physics

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