Opportunity knocks for atomic interferometers

Abstract

Optical interference is proof of the wave nature of light and matter–wave interferometers have also been shown to work for electrons and neutrons (by exploiting the de Broglie wavelength of the particles). Now a working interferometer for atoms has been demonstrated at the Massachusetts Institute of Technology(MIT) for the first time, in the sense that it uses “atomic beam splitters” to separate and recombine atomic beams (David W Keith et al. Phys. Rev. Lett. (1991) 66 2693). A simpler experiment at Konstanz University, Germany (O Carnal and J Mlynek Phys. Rev. Lett. (1991) 66 2689) has also demonstrated interference phenomena in atomic beams but a detailed description of the apparatus is not yet published. Atom interferometers will some day be useful in precision metrology, mass tomography, precision gyroscopes, general relativity, fundamental quantum mechanics and atomic physics.