ABSTRACT:
The equivalence principle (EP) states that in a uniform gravitational field all bodies fall with the same acceleration regardless of their mass and internal structure. The equivalence principle is the underlying foundation of General Relativity, our current theory of gravity. Despite the fact that General Relativity has passed many precision experimental tests, it is fundamentally incompatible with the quantum nature of the standard model. Modern theories, like string theory and quantum gravity, predict violations of the equivalence principle.
In the experiments conducted at the University of Washington a composition dipole is suspended from a thin fiber in a vacuum vessel that rotates with constant rate. A violation of the equivalence principle would yield to a differential acceleration of the two materials to a source mass located to the side of this torsion balance.
Any differential acceleration can be detected as a sinusoidal excursion of the torsion pendulum at the rotation period. In this talk I will present measurements of the differential acceleration with an uncertainty of 3 fm/s2. These measurements set new limits on equivalence principle violating interactions between the composition dipole and a variety of sources.
