AWhat changed
Lamporesi and colleagues used two freely falling rubidium samples as a differential atom interferometer while moving tungsten source masses between two configurations. Comparing the observed phase shift with a numerical gravitational-field model yielded an estimate of the Newtonian constant G of 6.667 × 10⁻¹¹ m³ kg⁻¹ s⁻², with separate reported statistical and systematic uncertainties. In a later experiment using the same apparatus lineage, Rosi and colleagues reported G = 6.67191(99) × 10⁻¹¹ m³ kg⁻¹ s⁻² with a combined uncertainty of about 150 parts per million.
Scientific scope
Lamporesi and colleagues used two freely falling rubidium samples as a differential atom interferometer while moving tungsten source masses between two configurations. Comparing the observed phase shift with a numerical gravitational-field model yielded an estimate of the Newtonian constant G of 6.667 × 10⁻¹¹ m³ kg⁻¹ s⁻², with separate reported statistical and systematic uncertainties. In a later experiment using the same apparatus lineage, Rosi and colleagues reported G = 6.67191(99) × 10⁻¹¹ m³ kg⁻¹ s⁻² with a combined uncertainty of about 150 parts per million. The result uses modeled mass distribution and atomic trajectories, ellipse fits, measured positions and velocities, and estimated systematics. The paper reports statistical uncertainty ±0.011 and systematic uncertainty ±0.003 in units of 10⁻¹¹ m³ kg⁻¹ s⁻²; lower than 100 parts per million accuracy was a future prospect, not achieved here. The instrument uses two source-mass configurations and common-mode rejection, and reports two runs in February and May 2007. The authors cite earlier atom-interferometric gravity measurements and prior source-mass demonstrations, including Fixler and colleagues; no claim of first atom-based G measurement is made. Exact publication comparison and raw-data replay were not performed. The 2014 result uses a separate July 2013 data run with the same source-mass platform lineage and a source-specific five-author byline; it is not an independent replication of the apparatus. Its value depends on Monte Carlo trajectory and mass models, ellipse fits and measured systematic corrections; the 150 ppm uncertainty is reported, not independently reproduced. Its printed uncertainty table gives 148 ppm before rounding. The 2008 below-100-ppm and 2014 below-10-ppm statements are prospects, not demonstrated results.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The result uses modeled mass distribution and atomic trajectories, ellipse fits, measured positions and velocities, and estimated systematics. The paper reports statistical uncertainty ±0.011 and systematic uncertainty ±0.003 in units of 10⁻¹¹ m³ kg⁻¹ s⁻²; lower than 100 parts per million accuracy was a future prospect, not achieved here. The instrument uses two source-mass configurations and common-mode rejection, and reports two runs in February and May 2007. The authors cite earlier atom-interferometric gravity measurements and prior source-mass demonstrations, including Fixler and colleagues; no claim of first atom-based G measurement is made. Exact publication comparison and raw-data replay were not performed. The 2014 result uses a separate July 2013 data run with the same source-mass platform lineage and a source-specific five-author byline; it is not an independent replication of the apparatus. Its value depends on Monte Carlo trajectory and mass models, ellipse fits and measured systematic corrections; the 150 ppm uncertainty is reported, not independently reproduced. Its printed uncertainty table gives 148 ppm before rounding. The 2008 below-100-ppm and 2014 below-10-ppm statements are prospects, not demonstrated results.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
- Determination of the Newtonian Gravitational Constant Using Atom Interferometry
- Precision Measurement of the Newtonian Gravitational Constant Using Cold Atoms
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
Full scientific record · Browse contribution grades · Request a correction