Band Crossings for Periodic
I will try to give an outline of some of the results obtained with Frederic
during my PhD thesis concerning the semiclassical analysis of periodic
media subject to exterior forces. Our goal has been to derive transport
equations for periodic versions of Wigner transforms associated with
oscillating solutions of a Schroedinger equation. A posteriori I can say
that the main problems we had to face up have all been concerned with the
crossings of energy levels and their possible interactions.