Testing sub-gravitational forces on atoms from a miniature in-vacuum source mass

• Published in: Nature physics Vol. 13; no. 10; pp. 938 - 942
• Main Authors: Jaffe, Matt, Haslinger, Philipp, Xu, Victoria, Hamilton, Paul, Upadhye, Amol, Elder, Benjamin, Khoury, Justin, Müller, Holger
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.10.2017
• Subjects: Astronomical models; Atom interferometry; Atomic properties; Atoms & subatomic particles; Cesium; Cosmology; Dark energy; Falling; Gravitation theory; Gravitational constant; Gravitational effects; Gravitational fields; Gravity; Gravity effects; Interferometers; Interferometry; Molecular clusters; Scalars
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys4189

Traditional gravity measurements use bulk masses to both source and probe gravitational fields. Matter-wave interferometers enable the use of probe masses as small as neutrons, atoms and molecular clusters, but still require fields generated by masses ranging from hundreds of kilograms to the entire Earth. Shrinking the sources would enable versatile configurations, improve positioning accuracy, enable tests for beyond-standard-model ('fifth') forces, and allow observation of non-classical effects of gravity. Here we detect the gravitational force between freely falling caesium atoms and an in-vacuum, miniature (centimetre-sized, 0.19 kg) source mass using atom interferometry. Sensitivity down to gravitational strength forces accesses the natural scale for a wide class of cosmologically motivated scalar field models of modified gravity and dark energy. We improve the limits on two such models, chameleons and symmetrons, by over two orders of magnitude. We expect further tests of dark energy theories, and measurements of Newton's gravitational constant and the gravitational Aharonov-Bohm effect.