Abstract:
Recent attempts to modify gravity at long distances to explain cosmic acceleration generally introduce new forces, for instance a scalar force, that must be screened in the solar system to satisfy stringent experimental constraints. We will discuss how such screening mechanisms might lead to O(1) equivalence principle violations - in suitable astronomical environments - namely, objects with different degrees of screening fall at different rates. Proposals to observe such effects, or rule out such theories, will be discussed.
Coffee and tea will be served 20 minutes prior to the seminar.