Light and Matter Id / Licht und Materie Id

The dynamical properties of solids have recently attracted renewed interest in connection with the increasing understanding of phase transitions and re­ lated phenomena. In particular, soft modes or, more generally, phonon ''anom­ alies'' seem to play an important role in structural and electronic phase tran­ sitions, such as ferroelectric or superconducting transitions. The understanding of the m...