Bragg diffraction in atomic systems in quantum degeneracy conditions

Studies of the scattering of light on systems of identical atoms under conditions of their quantum degeneracy have been reviewed. The formation of a periodic spatial structure caused by the interference of material waves is responsible for coherent resonance scattering similar to Bragg diffraction on regular spatial inhomogeneities. The interference of macroscopic material waves that is observed in experiments with a Bose–Einstein condensate forms a dielectric medium in the region of optical transparency of the sample that has the properties of a photonic crystal. Common characteristics and differences between the scattering of light on atomic systems under quantum degeneracy conditions and scattering on one-dimensional atomic lattices where the positions of atoms are described by classical statistics have been discussed.