1.   Already clocks using cold atoms are a hundred times more accurate than the best clocks using ordinary atomic beams.

2.   So what you do is make a fountain of these cold atoms so that an atom remains stationary for a longer period at the top of its trajectory.

3.   So waves of cold atoms can be used to measure changes in gravity.

4.   So the wave behaviour of cold atoms is easier to observe than that of ordinary atoms.