Atom Interferometer Measurement of the Newtonian Constant of Gravity

Fixler, J. B.
Foster, G. T.
McGuirk, J. M.
Kasevich, M. A.

¹Department of Physics, Stanford University, Stanford, CA 94305-4060, USA. ²Department of Physics and Astronomy, City University of New York, Hunter College, New York, NY 10021, USA. ³Department of Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material: www.sciencemag.org/cgi/content/full/315/5808/74/DC1; Materials and Methods; References

22 September 2006; accepted 22 November 2006

10.1126/science.1135459

Science 315(5808):p 74-77, January 5, 2007.

We measured the Newtonian constant of gravity, G, using a gravity gradiometer based on atom interferometry. The gradiometer measures the differential acceleration of two samples of laser-cooled Cs atoms. The change in gravitational field along one dimension is measured when a well-characterized Pb mass is displaced. Here, we report a value of G = 6.693 × 10⁻¹¹ cubic meters per kilogram second squared, with a standard error of the mean of ±0.027 × 10⁻¹¹ and a systematic error of ±0.027 × 10⁻¹¹ cubic meters per kilogram second squared. The possibility that unknown systematic errors still exist in traditional measurements makes it important to measure G with independent methods.