Atom Interferometry in a Bose-Einstein Condensate Ratchet

Abstract

Interferometry is at the heart of all precision measurements. Atoms, like light, exhibit wave-like properties which makes it possible to construct an atom interferometer. The major optical elements essential to an interferometers are used to separate the stream of particles into two diverging atom waves, to bring them back towards each other and third to make them interact with each other. These atom optics are implemented experimentally by pulses of finely tuned light. Atom interferometry is achieved in ultra-cold 87Rb by realizing a ratchet and reversing it. A microwave pulse is used as a beam splitter to split the atoms into two internal states and ratchet steps are carried out to take the two atom waves apart and to bring them back together. Another microwave pulse is used to make the two beams interact with each other to be able to observe an interference pattern. The interference is illustrated by the change in the population of the final states.