Sub-shot-noise-limited measurements with Bose-Einstein condensates

We discuss practical schemes for using entangled Bose-Einstein condensates to detect phase shifts with a resolution better than the shot-noise limit. We begin by outlining a procedure for demonstrating how squeezed matter waves can be used to make measurements by simply lowering and raising a potential barrier between two condensates. The phase shift is read out by a scheme which involves releasing the condensates and studying the collapses and revivals of the visibility of the observed interference fringes. Finally we show how this scheme could be extended to measurements of other quantities such as gravity. All the steps of this process are attainable with current technology and so may provide a practical route for achieving enhanced resolution measurements with matter waves.