We study the lifetime of an atom trapped in an optical vertical lattice in proximity of a massive surface using a complex-scaling approach. We analyze how the presence of the surface modifies the known lifetimes of Wannier-Stark states associated with Landau-Zener tunneling. We also investigate how the existence of a hypothetical short-distance deviation from Newton's gravitational law could affect these lifetimes. Our study is relevant in order to discuss the feasibility of any atomic-interferometry experiment performed near a surface. Finally, the difficulties encountered in applying the complex-scaling approach to the atom-surface Casimir-Polder interaction are addressed.

• Received 14 February 2013

DOI:https://doi.org/10.1103/PhysRevA.88.013411