UQ researchers extend Einstein's work

Tuesday, 20 December 2005

One of the surprising and unsettling aspects of the early development of quantum mechanics was the realisation that quantum properties do not have a defined existence until they are actually measured. Einstein, for one, was never happy with this view and insisted that certain properties of quantum particles should be "real" before any measurements were made, rather than having a "ghostly", uncertain existence until actually observed.

Along with Podolsky and Rosen, he outlined the Einstein-Podolsky-Rosen (EPR) paradox in an attempt to show that quantum mechanics might not be a complete theory. So far, the paradox has only been tested experimentally with photons, with the conclusion that the "ghostliness" which appalled Einstein is actually real. It has not been tested with massive particles such as atoms and molecules for which it may be more difficult to accept this quantum "ghostliness".

Physicists at the University of Queensland node of the Australian Research Council Centre of Excellence for Quantum-Atom Optics (ACQAO) have now proposed  a way to use another of Einstein's major contributions to 20th century physics, Bose-Einstein condensation, to test the paradox with atoms.

Karen Kheruntsyan, Murray Olsen and Peter Drummond have suggested that recent advances in the manipulation of atomic and molecular Bose-Einstein condensates can be adapted to perform a variant of the famous EPR thought experiment with correlated beams of atoms produced from a molecular Bose-Einstein-Condensate [see Phys. Rev. Lett. 95, 150405 (No. 15, 7 October 2005); "Einstein-Podolsky-Rosen correlations via dissociation of a molecular Bose-Einstein condensate."].

Related experiments with photons marked the emergence of quantum optics, the first field in which many fundamental properties of quantum mechanical theory were tested in laboratories. The extension of these techniques to atomic and molecular physics will open a whole new field for fundamental tests with interacting massive particles. Unlike photons, these particles feel the force of gravity and hence can be used to test quantum mechanics in a new way.

ACQAO involves research carried out at three Australian universities including UQ, the Australian National University and Swinburne University of Technology.

Read more at UQ News Online:
http://www.uq.edu.au/news/index.html?article=8718

Media:
For further information, contact: Ms Linda Schumacher (Operations Manager, UQ Node of ACQAO), phone +61-7-33653427, email lindaphysics.uq.edu.au; Dr Karen Kheruntsyan, phone +61-7-33653420, email kheruntsphysics.uq.edu.au; Dr Murray Olsen, phone +61-7-33469826, email mkophysics.uq.edu.au; Professor Peter Drummond, phone +61-7-33653404, email drummondphysics.uq.edu.au.