Editor's Summary
16 March 2006
Three Into One Does Go
In the bizarre world of quantum physics, three interacting particles can form a loosely bound system even if the two-particle attraction is too weak to allow for the binding of a pair. This exotic trimer state was predicted 35 years ago by Russian physicist Vitali Efimov, who found a remarkable and counterintuitive solution to the notoriously difficult quantum-mechanical three-body problem. Efimov's well known result was a landmark in theoretical few-body physics, but until now these exotic states had not been demonstrated experimentally. Now that has been achieved, in an ultracold gas of caesium atoms. The existence of this gas confirms key predictions and opens up few-body quantum systems to further experiment.
News and Views: Quantum physics: A ménage à trois laid bare
Quantum bodies that can't settle down together in pairs get on fine in a cosy threesome. This startling claim about the private life of particles has just seen its first experimental confirmation.
Brett D. Esry and Chris H. Greene
doi:10.1038/440289b
Letter: Evidence for Efimov quantum states in an ultracold gas of caesium atoms
T. Kraemer, M. Mark, P. Waldburger, J. G. Danzl, C. Chin, B. Engeser, A. D. Lange, K. Pilch, A. Jaakkola, H.-C. Nägerl and R. Grimm
doi:10.1038/nature04626