  Current acceleration of the cosmic expansion leads to coincidence as well as
fine-tuning issues in the framework of general relativity. Dynamical scalar
fields have been introduced in response of these problems, some of them
invoking screening mechanisms for passing local tests of gravity. Recent lab
experiments based on atom interferometry in a vacuum chamber have been proposed
for testing modified gravity models. So far only analytical computations have
been used to provide forecasts. We derive numerical solutions for chameleon
models that take into account the effect of the vacuum chamber wall and its
environment. With this realistic profile of the chameleon field in the chamber,
we refine the forecasts that were derived analytically. We finally highlight
specific effects due to the vacuum chamber that are potentially interesting for
future experiments.
