Gravitational Tests of Lorentz Symmetry with Atom Interferometers

Lorentz-symmetry violation offers a potential probe for new physics at the Planck scale. At currently accessible energies, these violations are described by the Standard-Model Extension (SME). In this talk I will provide an outline of the SME and discuss new sensitivities to Lorentz violation attainable in atom interferometer experiments, arising from gravitational interactions with atoms.