UK Physics & Astronomy


Physics & Astronomy Colloquium



3:30 PM, Friday, March 3, 2006

Room 155, Chem-Phys Building



Dr. Aharon Kapitulnik

Departments of Applied Physics and Physics
Stanford University


``Constraints on Yukawa-Type Deviations from Newtonian Gravity at sub-100 Microns''


Recent theories of physics beyond the standard model have predicted deviations from Newtonian gravity at short distances. In order to test these theories, we have a built an apparatus that can measure attonewton-scale forces between small masses separated by distances on the order of 25 microns. A micromachined silicon cantilever was used as the force sensor, and its displacement was measured with a fiber interferometer. We have used our measurements to set bounds on the magnitude alpha and length scale lambda of Yukawa-type deviations from Newtonian gravity; our results presented here yield the best experimental limit in the range of lambda between 5 and 50 microns. We also discuss new experiments that are underway in which substantial improvements are expected.

Refreshments will be served in CP 155 at 3:15 PM