Measurements of Gravity-Like Forces at Small Distances

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This project uses a novel apparatus for the measurement of gravity-like forces in the 10 micrometer to 100 micrometer range, having an estimated sensitivity of order Newton's gravity at this range of length scales. The technique is similar to that of a miniature Cavendish-type experiment, with the original torsion balance replaced by the spring of a cantilever beam. A first generation of the apparatus was already built and tested yielding a first set of data in a new excluded range which improves previous bounds by more than four orders of magnitudes in interaction strength at the length scale of approximately 10 micrometers.The project is expected to impact science at all levels. First, all theories that attempt to unifygravity with the other forces in nature involve the modification of Newton's law of gravity. The experiment will therefore guide the theory in the currently most exciting range of length scales. The first set of data put new and important constraints on a large class of string theories wheremoduli particles are expected to appear as a consequence of broken supersymmetry. Since Newton's law of gravity is one of the first concepts of nature that young students learnat grade school, the possible modifications of this law at short, but mentally comprehensible, distances will ignite young peoples' minds. The problem becomes even more interesting as the technology used in the proposed experiment is at the cutting edge of micro-fabricated devices.