Determination of the Newtonian Gravitational Constant Using Atom Interferometry

We present a new measurement of the Newtonian gravitational constant G based on cold-atom interferometry. Freely falling samples of laser-cooled rubidium atoms are used in a gravity gradiometer to probe the field generated by nearby source masses. In addition to its potential sensitivity, this method is intriguing as gravity is explored by a quantum system. We report a value of G=6.667×10^-11 m³ kg^-1 s^-2, estimating a statistical uncertainty of ±0.011×10^-11 m³ kg^-1 s^-2 and a systematic uncertainty of ±0.003×10^-11 m³ kg^-1 s^-2. The long-term stability of the instrument and the signal-to-noise ratio demonstrated here open interesting perspectives for pushing the measurement accuracy below the 100 ppm level.