Probing gravity by holding atoms for 20 seconds

Abstract

Trapped atoms to probe gravity Exploiting the wave nature of atoms in an interferometer setup can be used to provide a precise measure of gravity. The precision is limited to the time scale of the interferometric measurement, which in turn is limited to the distance that the atoms drop, typically just over a couple of seconds for a 10-meter drop tower. Xu et al. describe a trapped atom interferometer in which the interrogation time of the interferometric measurements can be extended to 20 seconds. The new interferometer design and subsequent improved precision can be used to make fundamental tests of general relativity as well as precision measurements of other potentials. Science , this issue p. 745