Null Test of Newton's Law of Gravitation on a 100-Micrometer Scale

University Of Maryland, College Park, College Park MD

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The objective of this research is to test Newton's inverse-square law of gravitation to 1% at a 100-micrometer range and to search for extra dimensions or other new physics down to a few tens of micrometers. The experiment will be cooled to liquid helium temperatures. To minimize Newtonian errors, the experiment employs a near-null source, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are positioned on the two sides of the source mass at close proximity. As the source is driven, the differential acceleration signal across the test masses should appear at twice the drive frequency due to symmetry. The signal is detected by a superconducting differential accelerometer, which is a highly sensitive gravity sensor. This research will explore the very nature of spacetime and test foundations of General Relativity and theories beyond the Standard Model of particle physics. The observation of a deviation from Newton's law at short distance would revolutionize our understanding of gravity, could be an approach the potential experimental confirmation of string theory, and could possibly shed light on the mystifying cosmological constant problem. This sort of research is basically understandable and exciting to the public, thus stimulating their interest in fundamental science. Further refinement of the cryogenic techniques that this laboratory has developed for measuring extremely weak forces is of potential value in a variety of other fields of precision measurement.