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 linear partial differential equation of the hyperbolic type, whose prototype is the wave equation (or the Helmholtz equation if time-periodic solutions are considered). Nowadays, the numerical techniques for solving the basic academic problems are well mastered. However, the resolution of complex wave propagation problems close to real applications still poses (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 conception of new numerical methods, more and more accurate and high performing.

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

• The treatment of more and more complex problems (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 or interfaces, small homogeneities, homogenization, ...).

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