Abstract

Waves in periodic media play a key role in many physical and mathematical theories, as well as applications: the band theory of solids, electromagnetic and acoustic waves in artificial periodic structures, photonic-crystal fibers, negative refraction, topological lasers, and more.

Central in the colloquium are the three mysteries of periodic media:
1. Magnetic effects can be produced by intrinsically nonmagnetic materials.
2. The behavior of evanescent (exponentially decaying) waves at high frequencies is governed, in a very peculiar way, by the behavior of propagating waves at much lower frequencies.
3. Properties of surface waves can be deduced from the properties of waves in the bulk.

The emphasis is on the essence of the physical phenomena and respective mathematical models. Technical details will be kept to a minimum but can be discussed after the session.