File talk:Frontgroupphase.gif

Isn't this animation misleading? In all realistic materials, the group velocity is (similar or) smaller than the phase velocity. The exception is anomalous dispersion, which is accompanied by very high absorption. Either should be taken into account in the animation. Basically the medium here seems to break causality (see Kramers-Kronig relations). --FDominec (talk) 12:38, 26 July 2021 (UTC)