Collisional decoherence observed in matter wave interferometry

One of the corner stones of quantum mechanics is the wave-particle duality of massive objects.According to quantum theory even complex particles, such as the C70 fullerene buckyball shown on the right side, may exhibit the interference properties of a wave.

We study the loss of spatial coherence in the extended wave function of fullerenes due to collisions with background gases. From the gradual suppression of quantum interference with increasing gas pressure we are able to support quantitatively both the predictions of decoherence theory and our picture of the interaction process. We thus explore the practical limits of matter wave interferometry at finite gas pressures and estimate the required experimental vacuum conditions for interferometry with even larger objects.

Klaus Hornberger, Stefan Uttenthaler, Björn Brezger, Lucia Hackermüller, Markus Arndt & Anton Zeilinger

Phys. Rev. Lett. 90, 160401 (2003)
arxiv.org/abs/quant-ph/0303093