Narrow Results

We report on the latest determination of the Newtonian gravitational constant G using our atom interferometry gravity gradiometer. After a short introduction on the G measurement issue we will provide a description of the experimental method employed, followed by a discussion of the experimental results in terms of sensitivity and systematic effects. Finally, prospects for future cold atom-based experiments devoted to the measurement of this fundamental constant are reported.

We have used a torsion-strip balance to perform continuous measurements of the Newtonian constant with a rate of ≈100 samples/day and searched for temporal variations in G over sidereal day time scales. We have operated the balance continuously for five months and here we present the details of the experimental campaign and of the analysis that provides upper-limits at the ppm level.