Harvard Physicists Make Light Dance

tetrikphimvin and others clued us to the latest work by Harvard's Lene Vestergaard Hau, being published today in the journal Nature. The NYTimes has a good layman's overview of how Hau's team encoded a light beam in a clump of atoms and later reconstituted it elsewhere. The Harvard Gazette offers additional details, a photo, and video links.

Comments

Re:relativity

[TexVex]

If I understand correctly, light travels more slowly through translucent substances because the photons are being absorbed and re-emitted by the electrons in them. The photons travel at c until they hit an atom's electron shell. The electron absorbs the photon, quantum leaps to a higher energy state, then immediately releases the absorbed energy as another photon and returns to its rest state. That whole process takes time, effectively slowing down a pulse of light. The light is still travelling at c between atoms.

In the experiment being discussed in the article, it sounds like they are stopping the process at the point where the photons have been absorbed by matter, and delaying their being re-emitted for quite a long time (relatively speaking). The light is being stopped, but not by causing photons to travel more slowly than c. It's being stopped by keeping the photons' energy bottled up inside the Bose-Einstein condensate.