Section: Research Program
General description
Our activity relies on the existence of boundary value problems established by physicists to model the propagation of waves in various situations. The basic ingredient is a partial differential equation of the hyperbolic type, whose prototype is the wave equation (or the Helmholtz equation if timeperiodic solutions are considered). Nowadays, the numerical techniques for solving the basic academic problems are well mastered. However, the solution of complex wave propagation problems close to real applications still raises (essentially open) problems which constitute a real challenge for applied mathematicians. In particular, several difficulties arise when extending the results and the methods from the scalar wave equation to vectorial problems modeling wave propagation in electromagnetism or elastodynamics.
A large part of research in mathematics, when applied to wave propagation problems, is oriented towards the following goals:

The design of new numerical methods, increasingly accurate and efficient.

The development of artificial transparent boundary conditions for handling unbounded propagation domains.

The treatment of more and more complex configurations (non local models, non linear models, coupled systems, periodic media).

The study of specific phenomena such as guided waves and resonances, which raise mathematical questions of spectral theory.

The development of approximate models via asymptotic analysis with multiple scales (thin layers, boundary layers effects, small heterogeneities, homogenization, ...).

The development and the analysis of algorithms for inverse problems (in particular for inverse scattering problems) and imaging techniques, using data from wave phenomena.