Torsion balances provide a table-top experimental tool to test the equivalence principle and inverse square law of gravity, properties of gravity that have recently been called into question. Modern theories of quantum gravity predict new spatial dimensions that may lead to an observable violation of the inverse square law and new scalar interactions that violate both the equivalence principle and inverse square law. The 100 micron length scale associated with the dark energy that pervades the universe may also lead to a violation of the inverse square law at this distance. Our group at the University of Washington has developed torsion balances to test these laws. Our experiments to test the inverse square law down to length scales of 60 microns will be described and our latest results will be presented.

ANL Physics Division Colloquium Schedule