Newtonian gravitational constant

Figures

Figure 1: Sketch of the experiment.
The Rb atom interferometer operates as a gravity gradiometer and the W masses are used as the source of the gravitational field. For the measurement of , the position of the source masses is alternated between configurations F and C. Plots of gravitational acceleration (az) produced along the symmetry axis by the source masses are also shown for each configuration; a constant value for Earth’s gravity was subtracted. The spatial regions of the upper and lower atom interferometers are indicated by the thick lines. The vertical acceleration plots show the effect of source mass in cancelling the local gravity gradient at the positions of the atomic apogees.
Figure 2: Experimental data.
, Typical Lissajous figures obtained by plotting the output signal of the upper atom interferometer versus that of the lower one for the two configurations of the source masses. , Modulation of the differential phase shift for the two configurations of source masses for a given direction of the Raman beams’ vector. Each phase measurement is obtained by fitting a 360-point scan of the atom interference fringes to an ellipse. The error bars, not visible on this scale, are given by the standard error of the least-squares fit to the ellipse. c, Results of the measurements to determine . Each point is obtained by averaging the signals recorded for the two directions of the Raman vector (Methods). Data acquisition for each point took about one hour. These data were recorded on different days during one week in July 2013. The error bars are given by the combined errors in the phase angles of four ellipses. , Histogram of the data in c.
Figure 3: Comparison with previous results.
Result of this experiment for compared with the values obtained in previous experiments and with the recent CODATA adjustments. Only the experiments considered for the current CODATA 2010 value, and the subsequent BIPM-13 result, are included. For details on the experiments and their identification with the abbreviations used in the figure, see ref. 3 and the additional references in Methods.

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