Orateur
Description
Scalar-tensor theories are one of the most natural alternatives to general relativity (GR), where gravity is mediated by both a tensor field and a scalar field. Among the wide variety of scalar-tensor models proposed over the past decades, some are already ruled-out by lab experiments or astrophysical observations while others remain viable by means of screening mechanisms that dynamically suppress deviations from GR in classical fifth force searches. The hunt for such hypothetical scalar fields thus requires designing novel and intelligent experiments. Alas, this task is partly impeded by the difficulty to accurately model their effects in complex setups.
This talk will showcase femtoscope — a Python numerical tool based on the finite element method for solving Klein-Gordon-like equations that arise in particular in the symmetron or chameleon models. The novelty and most important feature of femtoscope is that it includes a careful treatment of asymptotic boundary conditions — that is when the behaviour of the field is only known infinitely far away from the sources — which is essential to obtain a physically-meaningful numerical approximation. I will then discuss some recent numerical studies conducted in order to ascertain fifth force detectability in Earth orbit, with emphasis laid on the effects of departure from spherical symmetry.
