Waveguides - Modellansatz

This is the third of three conversation recorded during the <a href="https://conference18.waves.kit.edu/">Conference on mathematics of wave phenomena</a> 23-27 July 2018 in Karlsruhe. Gudrun is in conversation with <a href="https://uma.ensta-paristech.fr/~bonnet">Anne-Sophie Bonnet-BenDhia</a> from <a href="https://uma.ensta-paristech.fr/">ENSTA</a> in Paris about transmission properties in perturbed waveguides. The <a href="https://en.wikipedia.org/wiki/Spectral_theory">spectral theory</a> is essential to study wave phenomena. For instance, everybody has experimented with resonating frequencies in a bathtube filled with water. These resonant <a href="https://en.wikipedia.org/wiki/Eigenvalues_and_eigenvectors#Vibration_analysis">eigenfrequencies</a> are eigenvalues of some operator which models the flow behaviour of the water. Eigenvalue problems are better known for matrices. For wave problems, we have to study eigenvalue problems in infinite dimension. L...