|5 July 2001|
Nature © Macmillan Publishers Ltd.
Quantum tunnelling: Forbidden fruit
Quantum tunnelling is a process by which quantum particles penetrate barriers, usually energy barriers, that are insurmountable to classical objects. In the 1980s physicists predicted the existence of 'dynamical' tunnelling, a quantum process that is classically forbidden by the conservation of a quantity other than the total energy of the system. Now the predictions have borne fruit with the observation of dynamical tunnelling in the ultra-cold atoms of a Bose-Einstein condensate. This opens up new opportunities for the study of nonlinear and classically chaotic systems in the quantum realm, and is also relevant to the study of quantum information.
Nature © Macmillan Publishers Ltd 2001 Registered No. 785998 England.