Atom interferometry for precision tests of gravity: measurement of G and test of Newtonian law at micrometric distances

We describe two experiments where atom interferometry is applied for precision measurements of gravitational effects. In the first, we measure the Newtonian gravitational constant G using an atom interferometry gravity-gradiometer which combines a rubidium fountain, a juggling scheme for fast launch of two atomic clouds, and Raman interferometry. We show that the sensor is able to detect the gravitational field produced by source masses and G is measured with better than 10-2 accuracy. In the second experiment, using ultra-cold strontium atoms in a vertical optical lattice and observing persistent Bloch oscillations for several seconds, we measure gravity acceleration with micromet-ric spatial resolution. We discuss the prospects for the study of gravitational forces at short distances and show that unexplored regions can be investigated in the search for deviations from Newtonian gravity.