Yb Bose-Einstein condensate Interferometer for h/m and $\alpha$*

We report high-precision results from a matter-wave interferometer using a Yb Bose-Einstein condensate (BEC) as a source. This contrast interferometer measures h/m, where h is Planck's constant and m is the mass of an ytterbium atom, which is used to determine the fine structure constant $\alpha$. We will present the techniques and results from our current apparatus, including the highest accuracy measurement to date using a BEC matter-wave interferometer and our progress toward measuring and controlling the effects of atomic interactions. We will also describe a new apparatus, currently under construction, which is designed to yield a sub-part-per-billion measurement of $\alpha$.