Bose-Einstein Condensates in Optical Quasicrystal Lattices
Résumé
We analyze the physics of Bose-Einstein condensates confined in quasi-periodic optical lattices (optical quasicrystals), which offer an intermediate situation between ordered and disordered systems. First, we analyze the time-of-flight interference pattern that reveals quasi-periodic long-range order. Second, we demonstrate localization effects associated with quasi-disorder as well as Bloch-like oscillations associated with the extended nature of the wavefunction of a Bose-Einstein condensate in an optical quasicrystal. In addition, we discuss in detail the crossover between diffusive and localized regimes when the quasi-periodic potential is switched on, as well as the effects of interactions.