Precision Measurement of the Newtonian Gravitational Constant Using Cold Atoms

Understand

About 300 experiments have tried to determine the value of the Newtonian gravitational constant, G, so far, but large discrepancies in the results have made it impossible to know its value precisely.

• The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G while keeping systematic effects under control.
• Most previous experiments performed were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish in 1798, and in all cases macroscopic masses were used.
• Here we report the precise determination of G using laser-cooled atoms and quantum interferometry.