  We have performed a number of experiments with a Bose-Einstein condensate
(BEC) in a one dimensional optical lattice. Making use of the small momentum
spread of a BEC and standard atom optics techniques a high level of coherent
control over an artificial solid state system is demonstrated. We are able to
load the BEC into the lattice ground state with a very high efficiency by
adiabatically turning on the optical lattice. We coherently transfer population
between lattice states and observe their evolution. Methods are developed and
used to perform band spectroscopy. We use these techniques to build a BEC
accelerator and a novel, coherent, large-momentum-transfer beamsplitter.
