19/04/2010 : Spectral gaps for light in a periodic ensemble of ultracold atoms
By Mauro Antezza post doc au laboratoire Kastler Brossel de l’Ecole Normale Superieure
We study the dispersion relation of light in a periodic ensemble of atoms. We develop a general theory valid for all periodic lattices, includig the atomic quantum motion, and properly renormalized. Whereas no omnidirectional spectral gap is known for light in a Bravais atomic lattice, we find that an omnidirectional gap occurs in a diamond atomic lattice. As a side result we solve a previous controversy on the occurrence of an omnidirectional gap in a cubic lattice.